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GEOLOGICAL SURVEY CIRCULAR 693 

Remote Sensing Platforms 

Remote Sensing Platforms 

By Alden P. Colvocoresses 

GEOLOGICAL SURVEY CIRCULAR 693 

1974 
United States Department of the Interior 

ROGERS C. B. MORTON, Secretary 

Geological Survey 

V. E. McKelvey, Director 

Free on application to the U.S. Geological Survey, National Center, Reston, Va. 22092 
Airborne platforms --------------------------

Balloons -------------------------------

General considerations ---------------

Free balloons -----------------------

Payload-altitude capabilities -----

Flight duration -----------------

Cost --------------------------- Stability -----------------------

Some meteorological considerations 

for free ballo6n flights --------

Project Stratoscope -------------

Powered balloons -------------------

Tethered ballo~ns -------------------

Descriptions and capabilities ____ _ 

Winches -----------------------

Tethers ------------------------ Tethered balloons for archeological 

studies -----------------------

Tethered and free balloon 

manufacturers ----------------

Aircraft -------------------------------

General considerations --------------

Platform stability ------------------

Descriptions of aircraft -------------

Low altitude, up to 9 km (29,500 

ft) service ceiling, propeller 

driven ----------------------- Cessna 180 Skywagon ______ _ 

Beechcraft Bonanza ---------

Cessna Super Skymaster ___ _ 

Beechcraft Queen Air ______ _ 

Grumman Mohawk ----------

Lockheed Y0-3A -----------

Medium altitude, 9 to 15 km 

(29,500-49,000 ft) service ceiling, propeller or jet.-----------

Rockwell Standard Jet Commander 1121 --------------

Gates Learjet --------------- Fairchild Hiller Porter _____ _ 

Lockheed NP3A Orion ------

Douglas Skywarrior RA-3B __ 

Lockheed NC130B (RC130) __ 

Boeing Stratolifter (RC135A) 

E-Systems (formerly LTV) 

L450F reconnaissance aircraft ---------------------

High altitude, service ceiling above 

15 km (49,000 ft) -----------

North American Rockwell X15-

General Dynamics/ Martin 

RB57F (WB57F) ---------

McDonnell Douglas RF-4C __ 

Lockheed U-2 --------------

CONTENTS 

Page 

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Airborne platforms-Continued 

Aircraft-Continued 

Des.criptions of aircraft-OoJ].tinued 

High altitude, service ceiling above 

15 km (49,000 ft)-Continued 

Lockheed SR71 (YF-12) ----

Bell helicopter 47G-3B-1 --------

Northrop Falconer drone --------

Goodyear blimps ---------------

Schweizer sailplane SGS 2-32 ----

Spacecraft ---~----------------------------­

General considerations ------------------

Data transmission ------------------

Platform stability ------------------

Descriptions of spacecraft ---------------

Experimental, unmanned, Earth viewing ------------------------------

Film return --------------------

Electronic data transmission, generally sun synchronous --------

Nimbus --------------------

TIROS ---------------------

Earth Resources Technology 

Satellite (ERTS) --------

Electronic data transmission, 

geosynchronous --------------- Application Technology 

Satellite (ATS) ----------

Synchronous Meteorological 

Satellite ( SMS) ----------

Proposed high-resolution 

geosynchronous systems __ _ 

Experimental, unmanned, extraterrestrial ------------------------

Ranger ------------------------

Lunar Orbiter ------------------

Surveyor -----------------------

Mariner (flyby) ----------------

Mariner 71 (Mars Orbiter) ------

Mariner Venus/Mercury ---------

Viking ------------------------- Pioneer (Jupiter) ---------------

Experimental, manned space flight __ _ 

Mercury ----------------------- Gemini ____ - _________ - ____ ------

Apollo -------------------------

Lunar Rover Vehicle ------------

Skylab -------------------------

Space Shuttle ------------------

Operational-NOAA -----------------

ESSA-TOS --------------------

Bibliography 

ITOS --------------------------

ITOS-D ------------------------

GOES -------------------------

III 

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FIGURE 1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9-12. 

13. 

14-24. 

26-28. 

29. 

30. 

31. 

32. 

33. 

34. 

35. 

36. 

37. 

ILLUSTRATIONS 

Graph showing payload- altitude capabilities of polyethylene free 

balloons ---------------------------------------------------- Graph showing payload- altitude capabilities of scrim free balloons 

Photograph of sunrise inflation of a 23,000-m3 polyethylene balloon_ 

Photograph of a tandem balloon system being reeled up in preparation for launch --------------------------------------------- Graph showing cost estimates for polyethylene and scrim free balloons ------------------------------------------------------- Map showing typical stratospheric wind fl~w at 37 km (120,000 ft) 

during midsummer ------------------------------------------

Map showing first approximation of areas in the northern hemisphere where balloon hovering and boomerang drifts are feasible 

during summer within the altitude range 14 km to 22 km ------

Diagram of hovering balloon flight C70~18 ---------------------

Photographs: 

9. Project Stratoscope II carrying a 3-ton optical telescope to 

an altitude of 24,400 m (80,000 ft) ------------------

10. The Stratoscope II telescope with guidance package and 

high-resolution camera equipment ---------------------

11. A 710-m3 spherical tethered balloon being prepared for 

launch at the White Sands Missile Range, N. Mex. ___ _ 

12. Single-hull British A-shape kite balloon with a volume of 

2,800 m3 --------------------------------------------

Graph showing payload versus altitude for British barrage balloons_ 

Photographs: 

14. Walking the balloon and aerial camera to the target area __ 

15. The radio-controlled Hasselblad EL 500 camera hung in its 

gimbal as seen from below ---------------------------

16. Cessna 180 Skywagon ----------------------------------

17. Beechcraft Bonanza A36 -------------------------------

18. Cessna 337 Turbo-System Super Skymaster --------------

19. Beechcraft Queen Air B80 -----------------------------

20. Grumman OV-1 Mohawk observation aircraft ------------

21. Lockheed Y0-3A quiet reconnaissance aircraft __________ _ 

22. Rockwell Standard Jet Commander 1121 ----------------

23. Gates Learjet 24 --------------------------------------

24. Fairchild Hiller Porter --------------------------------

25. Diagram of NASA 927 Lockheed NP3A Orion flight configuration ------------------------------------------- Photographs: 

26. Douglas Skywarrior RA-3B ---------------------------

27. Lockheed NC130B (RC130) Earth Resources Aircraft 

(NASA 929) ---------------------------------------

28. Boeing RC135A ---------------------------------------

Diagram of isometric view of Boeing RC135A showing the USQ-28 

aerial electrophotomapping system ---------------------------

Photograph of E-Systems L450F reconnaissance aircraft in piloted 

configuration ----------------------------------------------- Photograph of North American Rockwell X15 research aircraft __ _ 

Diagram of General Dynamics/Martin RB57F ------------------

Photograph of McDonnell Douglas (Phantom II) RF-4C ________ _ 

Diagram of McDonnell Douglas (Phantom II) RF-4C flight configuration --------------------------------------------------

Photograph of Lockheed U-2 ---------------------------------- Photograph of Lockheed SR71A strategic reconnaissance aircraft__ 

Diagram of USDA Forest Service helicopter fire spotter, Bell 47G3B-1 -------------------------------------------------------

IV 

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Page 

38-41. Photographs: 

38. Northrop Falconer surveillance drone ------------------- 57 

39. Goodyear blimp Columbia ------------------------------ 58 

40. Television camera mounted on blimp ;.l'Jayfiower --------- 58 

41. Schweizer sailplane SGS 2-32 -------------------------- 59 

42. Diagram of proposed film return Earth-sensing space vehicle 

(USGS) --------------------------------------------------- 59 

43. Photograph of aircraft recovering a capsule such as might contain 

film from an Earth-sensing spacecraft ----------------------- 59 

44. Diagram of Nimbus D satellite -------------------------------- 60 

45. Diagram of TIROS M spacecraft ------------------------------ 60 

46. Artist's conception of Earth Resources Technology Satellite 

(ERTS) --------------------------------------------------- 61 

47-49. Diagrams: 

47. ERTS system ----------------------------------------- 61 

48. ATS-B systems and interior experiments ---------------- 62 

49. ATS-B exterior experiments --------------------------- 62 

50. Artist's conception of ATS-F and ATS-G ---------------------- 62 

51. Artist's conception of Synchronous Meteorological Satellite (SMS) 63 

52. Diagram of a 6-satellite high-resolution geosynchronous Earthsensing system --------------------------------------------- 63 

53. Photograph of Ranger lunar probe ----------------------------- 64 

54. Artist's conception of Lunar Orbiter spacecraft ----------------- 64 

55. Photograph of Lunar Orbiter E, showing camera lens ------------ 64 

56. Diagram of Surveyor lunar lander ----------------------------- 65 

57. Photograph of Mariner 4 spacecraft (flyby version) ------------ 65 

58. Artist's conception of Mariner 9 spacecraft (Mars Orbiter) ______ 65 

59. Diagram of Viking spacecraft --------------------------------- 66 

60. Artist's conception of Pioneer spacecraft ----------------------- 67 

61. Artist's conception of Mercury, Gemini, and Apollo spacecraft ____ 67 

62. Photograph of Apollo service module, showing Scientific Instrument 

Module (SIM) ---------------------------------------------- 68 

63-66. Diagrams: 

63. Sketch of instruments carried in Apollo SIM bay -------- 68 

64. Sketch of Lunar Rover Vehicle, showing instruments ---- 68 

65. Skylab-A --------------------------------------------- 69 

66. Skylab-A, activation and operation-periods of occupancy__ 70 

67. Artist's conception of Space Shuttle --------------------------- 71 

68. Diagram of evolution of TIROS, TOS, ESSA satellites___________ 72 

69. Photograph of TIROS Operational Satellites (TOS) ------------ 73 

70. Photograph of interior of the Environmental Survey Satellite, 

ESSA 3 ---------------------------------------------------- 73 

71. Artist's conception of NOAA .Satellite ITOS -------------------- 74 

72. Diagram of NOAA Satellite ITOS-D -------------------------- 75 

v 
AFCRL 

APT 

ARPA 

ATS 

AVCS 

bps 

dm3 

EREP 

ERTS 

FAA 

f.l. 

FM 

GOES 

Hz 

inm 

ITOS 

kbps 

kn 

LST 

MAC 

ABBREVIATIONS AND ACRONYMS 

Air Force Cambridge Research Laboratories 

Automatic Picture Transmission 

Advanced Research Projects Agency 

Application Technology Satellite 

Advanced Vidicon Camera System 

Bits per second 

Cubic decimeter 

Earth Resources Experiment Package 

Earth Resources Technology Satellite 

Federal Aviation Agency 

Focal length 

Frequency Modulation 

Geostationary Operational Environmental 

Satellite 

Hertz 

International nautical mile 

Improved TIROS Operational System 

Kilobits per second 

Knot 

Large Space Telescope 

Military Airlift Command 

MATS 

~bps 

MHz 

NASA 

NOAA 

PCM 

PM 

SAM OS 

SEOS 

SIM 

SLAR 

SMS 

SPM 

TIROS 

TOS 

TV 

VHF 

VTPR 

VI 

Military Air Transport Service 

Megabits per second 

Megahertz 

National Aeronautics and Space Administration 

National Oceanographic and Atmospheric 

Administration 

Pulse Code Modulation 

Phase Modulation 

Satellite and Missile Observation System 

Synchronous Earth Observation Satellite 

Scientific Instrument Module 

Side-looking Airborne Radar 

Synchronous Meteorological Satellite 

Solar Proton Monitor 

Television Infrared Observation Satellite 

TIROS Operational Satellite 

Television 

Very High Frequency 

Vertical Temperature Profile Radiometer 
Rem~ote Sensing Platforms 

By Alden P. Colvocoresses 

The author of this report is actually the 

author-editor with major contributions by 

others as follows : George Nolan of AFCRL 

(balloons), David Landen of USGS (aircraft), 

Stanley Addess of USGS (NASA spacecraft), 

and Arthur Schwalb and Lewis J. Allison of 

NOAA (NOAA spacecraft). 

This report was initiated by the American 

Society of Photogrammetry as a chapter in the 

forthcoming "Manual of Remote Sensing." A 

preliminary version titled "Platforms," dated 

January 1972, has already been given limited 

distribution for reviewing purposes. 

Typical vehicles which carry remote sensors 

into the atmosphere or beyond into space are 

described and illustrated, and their performance 

characteristics are listed. No attempt is made 

to completely catalog or to cover the history of 

remote-sensing vehicles. Airborne platforms 

and spacecraft in use or defined as of 1971-73 

were selected from the vehicles which have 

gained widest acceptance, demonstrated a 

unique capability, or have been· defined for future remote-sensing missions. A wide variety of 

nonorbiting rockets have carried cameras and 

other sensors into space, but since current 

United States remote-sensing programs do not 

include rockets, except for astronomic observations, rockets are not included. However, as of 

1972, British industry was building a variety of 

rockets specifically designed as remote-sensing 

platforms. Except for a unique British kite balloon, only American platforms are covered, and, 

therefore, this circular could be viewed as a 

contribution to any international effort to cover 

the subject. 

Remote sensing of the Earth is the prime 

1 

consideration, but sensing of the other planets 

and moons is also considered. Astronomy, except to the extent indicated above, is not included nor is the measurement of the force 

fields such as gravity or magnetics. 

AIRBORNE PLATFORMS 

BALLOONS 

GENERAL CON SID ERA TIONS 

The objective of this section on free and 

tethered balloon platforms is to provide sufficient technical and descriptive information to 

the experimenter so that he can judge whether 

a balloon is an appropriate platform for his 

sensor. He can obtain an indepth understanding 

of balloon capabilities, limitations, and new 

developments by referring to the literature in 

the bibliography and contacting the organizations involved in balloon activities. 

Although balloons were used as camera platforms during the Civil War, it was not until the 

late 1950's that a serious program was initiated 

to utilize balloons for a wide variety of remotesensing experiments. By 1972, balloons had 

risen to above 49 km (160,000 ft) and carried 

a wide variety of sensors that looked at the 

Earth's surface, the atmosphere, and celestial 

bodies. Practically all remote-sensing balloon 

flights are unmanned, but manned balloon 

flights, particularly by astronomers, have also 

been successful (Stehling, 1971). 

The balloon is a remote-sensing platform 

which permits the experiment or operation to 

define the shape, size, and performance required 

of the carrier; however, the use of balloons is 

restricted by meteorological factors, especially 

by wind influences. 
FREE BALLOONS 

PAYLOAD-ALTITUDE CAP ABILITIES 

The current range of altitude and associated 

payload capabilities for free balloons are shown 

in figures 1 and 2. In figure 1, each curve represents a single, flight-proven balloon made from 

a superior quality, lightweight polyethylene 

film. (Not all of the existing balloon designs are 

included on the charts.) Scrim balloons are 

made from Mylar film laminated with a reinforcing scrim, or mesh, of Dacron thread. The 

high-strength scrim materials are used for 

carrying payloads much heavier than is possible with polyethylene balloons. Figure 2 indicates the range of payload-altitude capabilities 

for designated volumes of scrim balloons. 

Although it is convenient to designate the 

balloons shown by their volumes, it is important 

to note that each curve represents an individual 

design and may be very different from the 

others in gore pattern, material thickness, type 

and placement of reinforcements, and location 

of ducts, valves, etc. 

In addition to the weight of the sensor, the 

payload includes the weight of parachute, instrumentation for balloon command and control, tracking beacons or radar reflectors, 

ballast and rigging, and other structures. 

A gas valve located at the top of the balloon 

is a highly desirable component of a balloon 

platform. It gives the operator the flexibility of 

controlling ascent and descent rates to conform 

to a desired flight profile, or of changing altitude to take advantage of more favorable wind 

conditions. Furthermore, a valve provides an 

added means of bringing the balloon to Earth 

after payload separation. 

Figure 3 shows the inflation of a 23,000-m3 

polyethylene balloon shortly after sunrise-the 

time of day when surface winds are normally 

most favorable for launches. 

Operational requirements sometimes will 

necessitate the use of a tandem balloon system 

as shown in figure 4. In this system all of the 

lifting gas is contained in the top or launch balloon before release. As the system ascends, the 

expanding gas transfers into the main or bottom balloon. 

FLIGHT DURATION 

Zero-pressure balloons usually carry ballast, 

which may be released either to increase the 

ascent rate or to compensate for a descent 

caused by thermal effects. The quantity of 

ballast that can be carried determines the flight 

duration of a zero-pressure balloon. This weight 

factor is an important consideration in selecting 

the proper balloon to meet special flight-profile 

requirements or to achieve a flight longer than 

1 day. 

In contrast to the zero-pressure balloons, 

superpressure balloons are completely sealed 

and require no ballast. They float at a constantdensity altitude and are capable of flight durations of many months. The superpressure 

balloons, however, can carry payloads of less 

than 40 kg and are relatively expensive. Therefore, their use is generally restricted to special 

applications that involve long duration flights 

with lightweight sensors. 

COST 

Rough estimates of the costs of free balloon 

platforms made of polyethylene or scrim material may be made from figure 5. Costs for 

items such as helium, operations, flight-control 

instrumentation, and travel are not included. 

For payloads greater than 1,000 kg, polyethylene balloons are normally reinforced with load 

tapes and a cap on the top. 

2 

STABILITY 

The inherent stability of the free-floating 

balloon is one of its most attractive assets for 

scientific applications. If reasonable care is 

taken in mounting and packaging the instruments, camera systems, spectrometers, magnetometers, telescopes, and interferometers ·can 

be flown without difficulty. 

The motion of the payload is dependent upon 

the mechanical properties of the payload suspension system. As the partially inflated balloon 

ascends through the atmosphere, the loadline 

tends to wind and unwind in random fashion, 

causing the payload to rotate at rates that are 

usually much less than 2 r/min. At the same 

time, the payload may behave as a simple or 

compound pendulum. Angular displacements 
from the vertical of 2° or less are generally observed. Mter the system has reached float 

equilibrium, however, payload motions need not 

be considered for most types of experiments. 

Gradual changes in payload orientations do occur. Torsional rotation rates- are generally a few 

revolutions per hour with a maximum rate of 12 

r/h having been observed. Displacements from 

the vertical due to pendulum motion have been 

reported to be no greater than 0.5° or a horizontal displacement of the payload about 

1.4 x 10- 3 times the length of the loadline. 

SOME METEOROLOGICAL CONSIDERATIONS FOR 

FREE BALLOON FLIGHTS 

The horizontal trajectory of a free balloon is 

primarily determined by the winds it encounters while airborne. However, a considerable 

degree of trajectory control is possible by 

selecting periods of the year, as determined 

from climatology, when repeatable wind patterns exist and by controlling the balloon's altitude using ballast drops and gas valving. 

Three basic flight profiles may have application to the use of balloons as platforms for remote sensing of the Earth's surface: precision 

ballooning, station-keeping, and boomerang. 

Fundamental to these profiles is the occurrence 

during the summer of stratospheric easterlies, 

that is, winds blowing from the east. This 

phenomenon occurs annually and thus can be 

safely used for planning flight operations. A 

typical example of the summertime stratospheric easterlies is given in figure 6, which 

shows streamline analysis of rocketsonde wind 

observations at the 5 mb surface (approximately 36.6 km or 120,000 ft) on July 22, 1964. The 

lower boundary of these easterl~es is approximately 18.3 km (60,000 ft), and they extend upward with their strength increasing with altitude and also toward lower latitudes at the same 

altitude. Peak values occur during the latter 

part of July with minimum values at the beginning and end of summer. 

The stratospheric easterlies have been used 

for precision ballooning-operations in which a 

balloon overflies a specific geographical location, 

such as an instrumented area on a test range. 

One might also envision the utilization of this 

wind phenomenon for cross-country traverses of 

balloons carrying remote sensors. 

Station-keeping and boomerang balloon flight 

profiles are also associated with the summertime 

occurrence of the stratospheric easterlies. However, to achieve these profiles a layer of westerlies (winds blowing from the west) must exist 

below the stratospheric easterlies. In this situation there are opposite flows of air in adjacent 

layers of the atmosphere, providing the setting 

for a balloon to drift back and forth across an 

area of interest merely by changing altitude. 

Between these layers of easterlies and westerlies a minimum wind layer exists, which provides the opportunity to hover or station keep a 

balloon over a relatively small area for an extended period. Figure 7 gives information on 

locations in the Northern Hemisphere where 

balloon station-keeping and boomerang profiles 

can be flown. Figure 8 shows the horizontal and 

vertical trajectories of a station-keeping balloon 

flight which remained over an area having a 

radius of approximately 75 km (40 international nautical miles) for 72 hours. 

g 

PROJECT STRATOSCOPE 

By the late 1950's, astronomic experimenters 

found that when only one or two functions in 

the balloon were to be performed it was cheaper 

and more convenient to launch a variety of unmanned balloons rather than a more complex 

manned flight. Simple experiments could be sent 

aloft unmanned, with radio signals used to point 

the equipment, control the flight, and record the 

data. 

An unmanned project, Stratoscope, achieved 

a series of outstanding successes. Stratoscope I, 

proposed by Martin Schwarzchild, an astronomer at Princeton University, and funded by the 

Office of Naval Research was originally launched 

in 1957 and was quickly followed by several 

flights. The results included a series of very detailed pictures of solar surface granulations. By 

1963, a double-balloon system had taken a 3,150 

kg (7,000 lb) payload to an altitude of about 

24,400 m (80,000 ft). That year new infrared 

spectra were obtained of the Moon, Jupiter, and 

seven stars. 

Stratoscope II was sponsored by the National 

Science Foundation, the Office of Naval Research, and NASA. In 1970, this balloon lifted a 

radio-controlled 92-cm (36-in.) diameter tele-
scope and brought back extremely high resolution photographs of Jupiter, Uranus, two kinds 

of nebulas, and Seyfert galaxies whose bright 

nuclei resemble quasars (figs. 9 and 10). 

The performance characteristics of Stratoscope II were as follows : 

Ceiling: 24,400 m (80,000 ft). 

Size : Length, 200 m ( 660 ft) ; volume, 

148,600 m3 • 

Payload: 3,150 kg (7,000 lb). 

Special equipment: A 64-channel radio telemetry system provided a high degree of 

remote control. A guidance system for 

the remotely controlled telescope made 

by RCA Laboratories, Princeton, N.J., 

provided a pointing accuracy of 0.02 second of arc. A key element of Stratoscope 

II was a precise optical system with a 

180-kg (400-lb), 92-cm (36-in.) diameter primary mirror. The Stratoscope telescope was designed by Perkin-Elmer 

Corp., Norwalk, Conn. It had a 5.5-m 

(18-ft) main tube assembly with a 3.3-

m (11-ft) side arm forming an L-shaped 

telescope. The side arm held the guidance 

equipment, the camera equipment, and 

the high-resolution TV camera. A lowresolution TV camera was boresighted 

with the main telescope. After each 

flight, the system and the exposed film 

were returned to Earth. 

POWERED BALLOONS 

During 1972 the U.S. Air Force launched at 

least one powered balloon, Pobal, which has been 

reported by "Aviation Week and Space Technology" (1973). The balloon of 20,200 m3 

(710,000 ft 3 ) rose to a height of 18,300 m 

(60,000 ft) and was powered by a batterydriven slowly rotating propeller of 9 m (30 ft) 

diameter. The experiment had a successful duration of 3 hours after which the rudder became 

dislodged due to winds. A powered balloon as 

compared with the passive type has the advantage of being remotely controlled and, within 

limitations, being guided along a path or hovering over a given area. If successfully developed, 

this mode has considerable potential application 

as a remote-sensing platform. 

TETHERED BALLOONS 

The basic sources of the material that follows 

are listed in the references. Particular attention 

is directed to the "Tethered Balloon Handbook" 

prepared for the AFCRL by Myers (1968). This 

work is an authoritative compilation of the history, development, applications, and listings of 

available modern equipment for tethered balloon activities. A paper by Young (1968) presents an excellent overview of tethered balloon 

technology and. offers predictions for future 

capabilities. A report by Battelle Columbus 

Laboratories (1971) sponsored by ARPA provides both a survey and technical assessment of 

tethered balloon systems. 

When considering the use of tethered balloons, it is essential that the initial planning be 

concerned with the atmosphere and the air space 

in which the balloon will be flying. Are wind 

conditions and other meteorological factors 

favorable, and are there air-safety constraints 

imposed on the location of the desired operation? The restrictions imposed by meteorological factors will depend in large part upon the 

type of tethered balloon system being considered. The use of air space must be coordinated 

with the controlling agency. In the United 

States this is either the FAA or the responsible 

agency in the case of use of a restricted air 

space. FAA regulations pertaining to tethered 

balloons can be found in "Federal Aviation 

Regulations," pt. 101, v. 6. 

4 

Although tethered balloons have been associated historically with wartime, serving as both 

a passive means of defense against aerial attacks and as observation platforms for artillery 

spotters, present-day usage is much broader, 

encompassing a variety of scientific disciplines. 

Tethered balloons are being used to carry aloft 

various types of sensors, meteorological measuring equipment, communication relays, and 

antennas. 

DESCRIPTIONS AND CAP ABILITIES 

Tethered balloon systems are usually custom 

tailored for a particular operation. The three 

main types of tethered balloons in use are the 

sphere, the natural shape, and the single-hull 

aerodynamic or streamlined shapes in a variety 
of finenes~ ratios and fin designs. The hull design chosen for a system depends on such requirements as downwind displacement, altitude, 

payload, windspeed, flight duration, and anticipated life. The sphere has been used since the 

inception of tethered balloons and is far from 

obsolete. Although spheres are generally limited 

to winds below. 55 km/h (30 kn), there are several areas of the world where tethered systems 

utilizing a spherical balloon could be used several months per year to fly at altitudes up to 3,000 

m (10,000 ft) above sea level. The principal advantage of the sphere is its relatively low ·cost 

compared with the streamlined shapes. 

Figure 11 shows a 710-m3 spherical balloon 

readied for launch. This system employed three 

tether lines to assure control of the balloon in 

maintaining its position over a relatively small 

area. This particular balloon has been used repeatedly as a platform for a variety of experiments. It has, among other combinations of payload and altitude, the capability of carrying a 

200-kg (440-lb) payload to 1 km (3,300 ft) 

with a maximum wind of 35 km/h (20 kn). 

The natural shape, mainstay of free ballooning, also provides a suitable tethered balloon. Its 

principal advantage is relatively low cost. However, its use is limited to winds of less than 30 

km/h (15kn). 

Streamlined balloons have much higher windspeed limitations. They also tend to fly nearer 

to the tether point than spheres in the same 

wind fields on a single tether. Figure 12 is a 

picture of a 2,800 m3 single-hull A-shape kite 

balloon, designed and manufactured by Airborne 

Industries, Ltd., Leigh-on-the-Sea, Essex, England, previously called Lea Bridge Industries. 

This type of balloon was used in World War II. 

Figure 13 is a payload-altitude graph for the 

three most popular models. These curves were 

developed for 135 kg winch tension on the tether 

cable, 30°F superheat temperature of the balloon gas above ambient standard temperature, 

and a cable weight of 134 kg/km. Costs range 

from $15,000 to $35,000 and are subject to 

change. The envelopes of these balloons have 

safely withstood windspeeds in excess of 110 

km/h (60 kn). 

Modern tools, both theoretical (computerized 

models) (Myers and Vorachek, 1971; Doyle and 

5 

Vorachek, 1971 ; and Doyle and others, 1973) 

and experimental (instrumented flights) are being utilized to improve tethered balloons and 

also to provide accurate stability data for existing systems. The recently developed ARPA 

Family 2 balloons, for example, fly in 140-km/h 

(75-kn) winds. Measurements directly applicable to sensors have been obtained by cinetheodolite and telemetry at the U.S. Air Force 

tethered balloon facility in New Mexico. The 

data include position, velocity, accelerations, 

and pitch and roll of the payload on a 2,800-m3 

(100,000-ft 3 ) A-shape (modified BJ barrage) 

balloon with cable lengths up to 2,750 m (9,000 

ft) in winds to 50 km/h (27 kn) . Similar data 

were obtained using an 800-m3 (28,000-ft3 ) 

natural-shaped balloon on a tri-tether at altitudes up to 610 m (2,000 ft) in winds to 25 

km/h (13 kn). 

WINCHES 

Winches for tethered balloon operations are 

used to raise and lower balloons to the desired 

altitude and to make the necessary operational 

adjustments of the balloon altitude during flight 

operations. Relatively inexpensive hand-operated winches, or even fishing reels, may be used 

for small, low-altitude balloons. Power-driven 

winches come with a multitude of available features and can range in price from several hundred dollars to several hundred thousand dollars. 

Some of the features of power-driven winches 

for tethered balloon applications, which add significantly to the cost of the winch, are variable 

speed drives, capstan or traction drives, level 

wind mechanisms, and various line speed, tension, and footage-measuring instruments. The 

winch system installation may be permanent, 

mobile, or portable. 

Tethered balloon winches are rarely off-theshelf items and are usually custom tailored for 

a specific application. Many winch manufacturers have standard components from which 

special winches can be assembled, thereby eliminating much of the design time and expense 

which would otherwise be required. 

TETHERS 

All tethers require a suitably high tensile 

strength, a high strength-to-weight ratio, low 
drag, low stretch, torque stability, high flexibility, abrasion resistance, and easy splicing. 

Typical balloon-tethering configurations are the 

single, dual, or tri-tether arrangements. The 

different configurations offer the various degrees of freedom which are dictated by the 

intended balloon operations. In many instances 

the tether line is designed to serve additional 

purposes: to carry the antenna, to encase the 

power line running from ground to sensors, to 

support an array of sensors along its length or 

the tubing for transferring helium to the balloon, etc. Tapered or stepped-diameter tethers 

may be desired for high-altitude flights where 

the weight of a constant-diameter tether cannot be safely borne. Most tether manufacturers 

have the capabilities for producing a unique 

tether to fit a specific need. 

TETHERED BALLOONS FOR ARCHEOLOGICAL STUDIES 

Tethered balloons have been used successfully 

by Julian H. Whittlesey to support aerial cameras for recording and mapping archeological 

sites (figs. 14 and 15) in Turkey, Greece, Italy, 

and Cyprus. Camera altitudes ranged from 10 

to 610 m (30 to 2,000 ft), with Linhof, Graflex, 

and Hasselblad cameras in single and multiple 

(multiband) form. Aerodynamic airfoil balloons 

were also utilized in the presence of high winds. 

Various schemes were used to obtain stereoscopic coverage. Some of the sites photographed 

were in shallow water. The performance of the 

tethered balloons used by Whittlesey was as 

follows: 

Ceiling: From 10 to 610 m (30 to 2,000 ft). 

Windspeed: With parafoil or ovoid shape, 

flown in winds from 25 to 40 km/h (15 to 

20 kn). Spherical balloons were tethered 

in relatively calm winds up to 10 km/h 

5 kn). 

Size: Up to 20m3 (700 ft 3 ). 

Payload: From 1.4 kg to 2.8 kg (3 to 6lb). 

In one arrangement, an electrically advanced, 

radio-controlled Hasselblad EL 500 camera was 

hung in a gimbal from the tethered balloon by 

means of four lines (Whittlesey, 1970). This 

arrangement provided for an unusual degree of 

platform stability. The balloon was filled with 

hydrogen. The weight of the entire payload, consisting of calibrated camera, lens motor, powerpack, radio receiver, antenna, and magnesium 

gimbal mount, was 2.8 kg ( 6 lb) . The gross 

weight of the balloon and payload was 10 kg 

(23 lb) plus tether lines that weighed several 

kilograms. Remote-sensing equipment included 

a variety of small photographic cameras, which 

were either pneumatically or radio controlled 

from the ground. 

As a result of Whittlesey's work, the U.S. 

Geological Survey is investigating the use of 

tethered airfoil balloons as platforms for photographically recording paneled control points in 

support of photogrammetric mapping. 

TETHERED AND FREE BALLOON MANUFACTURERS 

The names and addresses of manufacturers 

of tethered and free balloons are listed below 

for the reader who wishes to obtain more current information, including the cost of a particular balloon. (This list may include companies 

no longer in the business and may omit new 

companies.) 

6 

Airborne Industries Ltd. 

Airborne Works 

Arteria~ Road 

Leigh-on-the-Sea 

Essex, England 

E. Bollay and Assoc., Inc. 

Boulder, Colorado 80302 

Dewey & Almy Chemical Division 

62 Whittemore A venue 

Cambridge, Massachusetts 02140 

Robert Fulton Company 

Old Ridgebury Road 

Danbury, Connecticut 06810 

Goodyear Aerospace Corp. 

1210 Massillon Road 

Akron, Ohio 44315 

ILC Industries, Inc. 

350 Pear Street 

Dover, Delaware 19901 

Jalbert Aerology Laboratory 

170 N.W. 20th Street 

Boca Raton, Florida 33432 

Raven Industries, Inc. 

Box 1007, 205 E. 6th Street 

Sioux Falls, South Dakota 57101 
G. T. Schjeldahl Company 

P.O. Box 170 

Northfield, Minnesota 55057 

Semco Balloons 

2002 N. 11th Street 

Coeur d'Alene, Idaho 83814 

Winzen Research, Inc. 

401 W. 84th Street 

Minneapolis, Minnesota 55420 

Some of these manufacturers provide complete operational balloon planning and field support. The National Center for Atmospheric 

Research, Boulder, Colorado 80302, is an excellent source of information on all phases of 

balloon operations. This organization also furnishes eomplete flight services. The balloon 

group at the Air Force Cambridge Research 

Laboratories, Bedford, Massachusetts 01730, 

provides complete balloon services for U.S. Air 

Force and Department of Defense relevant 

activities. 

AIRCRAFT 

GENERAL CO:"J"SIDERATIONS 

Praetically every type of aircraft built has 

been used, at one time or another, as a remote-sensor platform. From the aircraft types 

listed in "Jane's All the World's Aircraft" 

(Taylor) and others, a representative selection 

has been made from those currently utilized as 

remote-sensor platforms. A sizable number of 

conventionally powered aircraft are described, 

whereas only single examples have been selected for unconventional types, which include 

helicopters, drones (unmanned aircraft) , 

blimps, and sailplanes. Selected aircraft are 

described in abbreviated terms and additional 

data are available from Jane's, the aircraft 

manufacturer, or the organization using the 

aircraft. 

Conventional aircraft currently used for remote sensing vary in size from small singleengine piston-powered craft to the sophisticated 

4-engine jet military version of the Boeing 707 

(RC135) and the Lockheed SR71. The remotesensing application of widest use is in obtaining mapping photographs. Figures 16 to 19 

illustrate some of the smaller aircraft frequently used by private aerial mapping contractors in the United States. Small aircraft 

7 

of this class are used for most of the aerial 

photography in the United States for private 

and governmental organizations. Such planes 

are adequate for lower altitude aerial photography and other types of remote sensing where 

instrumentation is light and simple. 

A single-engine or light twin-engine aircraft 

is generally more economical and maneuverable 

than a large 2- or 4-motored aircraft; however, 

the selection of the aircraft should be based 

on the operator's intended use, the geography 

and meteorology of the operating area, the 

capital and operating cost, maneuverability, 

safety, performance, and ease with which the 

aircraft can be converted to remote-sensing 

operations. 

Planes used for remote sensing are usually 

either commercial or military types that are 

modified. Modification can be very expensive, 

and it is generally more economical to select 

an aircraft that requires minimum change. 

Technical details relative to the problems associated with selection and modification of aircraft for aerial photography can be found in 

the "Manual of Photogrammetry," (1966) ; the 

"Manual of Photographic Interpretation," 

( 1960) ; and the "Manual of Color Aerial Photography," (1968), all published by the American Society of Photogrammetry. Adapting aircraft for any other type of remote sensing is 

generally a highly s~pecialized operation which 

must be considered on a case-by-case basis. 

However, many nonphotographic sensors are 

designed to fit standard mapping-camera ports, 

and thus aircraft designed for mapping operations may be suitable, with minimum modification, for other remote-sensing operations. 

Remote sensors of the active, wave propagating 

form require considerable power, which may be 

a major consideration in the choice of aircraft. 

Jet aircraft have a high potential for remote 

sensing because of their excellent rate of climb, 

high operating ceiling, and maximum speed, 

but the cost of acquisition and conversion from 

commercial or military types restrict their 

wider use. High-altitude jet photography is being used increasingly for making photomaps 

and orthophotomaps where a single exposure 

may cover an entire map quadrangle. Most jet 

aircraft applications to remote sensing, however, are still limited to NASA experimental 
flights, government operations, and a few commercial firms. 

Very high altitude remote-sensing aircraft 

have to some extent become available to the 

civilian community. The X15 (fig. 31), which 

was strictly a research platform, demonstrated 

remote sensing (photography) from an altitude 

of more than 107 km (354,000 ft). The X15 

was a hybrid aircraft/ spacecraft since its flight 

trajectory carried it well above the atmosphere. 

Two other high-altitude aircraft types, the 

RB57F (fig. 32) and the U-2 (fig. 35), are 

now available for nonmilitary remote-sensing 

applications. These provide platforms at service ceilings of 18.3 km (60,000 ft) and 21.3 

km (70,000 ft). Military reconnaissance aircraft, such as the RF4C (fig. 33) and the SR71 

(fig. 36) have reported service ceilings of 15.2 

km (50,000 ft) and over 24.4 km (80,000 ft), 

but as yet they have not been used for civilian 

projects. 

Another consideration is the role of man in 

the aircraft. With balloons and spacecraft, man 

may or may not be aboard the platform, but 

aircraft are generally manned. However, remote-control systems are rapidly being developed to the point where unmanned aircraft may 

become practical. Completely automated aircraft have monitored atomic explosion tests, 

and drones are an accepted form of military 

reconnaissance. Even if the aircraft is manned 

with a pilot, the number of other people that 

actually fly is a prime consideration relative to 

the type of aircraft and cost of the flight. As 

operational systems are defined, they tend to 

become more automated; there appears to be 

no real reason why remote-sensing missions, 

once defined and tested, need a flight crew of 

more than one or two. The opposite extreme is 

to perform maximum onboard processing and 

evaluation with a sizable crew; however, this 

approach has not yet been shown to be practical. 

PLATFORM STABILITY 

In addition to the fundamental consideration 

of having an aircraft at the right place at the 

right time, the problem of platform stability is 

paramount. In general, a highly stable platform, free of both vibrations and long-period 

8 

oscillations, is desired. Constant motion of the 

platform relative to the scene is an expected 

condition and is, in fact, required for many 

remote-sensing missions. Compensation for the 

resulting image motion, if needed, is normally 

included in the design of a sensor system or its 

mount rather than the platform. Vibration, 

oscillation, or any other anomalies in the predetermined relative motion of the platform to 

the scene result in instability which has an 

overall degrading effect. 

Aircraft in the atmosphere are inevitably 

subject to two types of instability: (1) vibrations created by the engines or other parts of 

the aircraft, and (2) rotations (pitch, roll, and 

yaw) which occur principally because both the 

aircraft and the atmosphere are dynamic. There 

are two basic ways of eliminating or at least 

reducing instability. The first is to provide a 

mount which isolates the sensor from the aircraft vibration and, by gyros or similar devices, 

maintains the sensor attitudes with respect to 

the scene independent of aircraft rotations. 

Mounts of this type have been designed for 

general-purpose use by the U.S. Air Force, but 

they are normally coupled to a specific sensor, 

such as a mapping camera. The second approach to reducing instability is in the selection 

and design of equipment and the aircraft itself. A reciprocating engine creates considerable vibration, a turbine somewhat less, and 

a jet still less. Propellers and reciprocating 

engines create torque as well as vibrations, 

but torque is normally neutralized by differentially adjusting wing lift and rudder, or it 

may be eliminated by the use of counterrotating 

pairs of engines. Vibration is reduced and 

isolated by the use of appropriate engine 

mounts. If the remote sensing can be limited 

to specific relatively small areas, propellers may 

be feathered or the engines even shut down for 

the critical periods of time if the aircraft is so 

designed. A high-lift aircraft, such as the 

Porter (fig. 24), with the engine shut off can 

actually hover or glide over a given scene for 

at least half an hour provided that there is a 

75 km/h (40 kn) wind in which to head. The 

craft will, of course, be constantly losing altitude while the engine is shut down. Thus stability is affected by the type, number, and use 

of engines. The design of the airframe itself 

as well as the sensor location with respect to 
the aircraft center of gravity are other parameters that affect stability. Equipping the plane 

with autopilots, damping, and self-leveling devices may also reduce the amplitude as well as 

the rates of rotational motion. Heavily loaded, 

a plane flies at a steeper pitch than when the 

load is reduced; thus the sensor, if fixed to the 

aircraft, will change in attitude with the use 

of fuel. A cross wind will cause an aircraft to 

drift, and if the sensor is not adjusted accordingly, the pertinent sensor axis and the ground 

path of the aircraft will not be alined. 

A most important factor affecting aircraft 

stability is the local atmosphere. Winds, turbulence, and other aspects of atmospheric dynamics cause most platform instability. At any 

given point atmospheric dynamics will vary 

hourly and daily as well as seasonally. As a 

general rule the atmosphere becomes more 

stable with height, and at the operational altitudes of U-2's and SR71's atmospheric dynamic 

effects are almost negligible. Obviously the stability of a twin-engine jet at 20 or 25 km altitude is far better than that of a single-reciprocating engine aircraft at 5 km altitude. 

DESCRIPTIONS OF AIRCRAFT 

LOW ALTITUDE, UP TO 9 KM (29,500 FT) SERVICE 

CEILING, PROPELLER DRIVEN 

Cessna 180 Skywagon.-The Cessna 180 Skywagon (fig. 16) is a single-engine (230 hp), 

propeller-driven, high-wing aircraft capable of 

carrying as many as six passengers or equivalent. Gross weight is 1,270 kg (2,800 lb). First 

marketed in 1968, it has had considerable use 

as a mapping camera platform and is well 

adapted for sensor equipment up to 180 kg 

(400 lb) in weight. 

Performance : 

Service ceiling: 5,940 m (19,500 ft). 

Speed: Maximum cruising (75% power) 

at 1,980 m (6,500 ft) is 260 km/h 

(160 mi/h). Minimum or stalling is 

93 km/h (58 mi/h). 

Range: From 1,120 to 1,920 km (700 to 

1,200 mi) with long-range tanks. 

Special equipment: Optional electronics 

for aerial survey projects include navigation aids, blind-flying instruments, 

autopilot, wing-leveling stability augmentation, and turn coordinator. 

Beechcraft Bonanza.-The Beechcraft Bonanza (fig. 17) in the standard Model A36 is 

a single-engine, propeller-driven, low-wing aircraft with retractable landing gear. It is powered by a 285-hp Continental engine. The Model 

A36, marketed in 1968, was developed from the 

Model 35, which was introduced in 1946. Maximum gross weight of the A36 is 1,620 kg (3,600 

lb). Sensor (payload) capacity is estimated at 

360 kg (800 lb). 

9 

Performance: 

Service ceiling: 4,870 m (16,000 ft). 

Speed: Maximum cruising (75% power) 

at 1,980 m (6,500 ft) is 315 km/h 

(195 mi/h). Minimum or stalling, 

gear down, flaps 30° is 103 km/h (64 

mi/h) ; gear and flaps up is 120 km/h 

(75 mi/h). 

Range: From 1,290 km (800 mi) (75% 

power) at 1,980 m (6,500 ft) to 1,430 

km (890 mi) (55% power) at 3,050 m 

(10,000 ft). 

Special equipment: Optional equipment 

includes autopilot, dual controls, and 

marker beacon receiver. 

Cessna Super Skymaster.-The Cessna Super 

Skymaster (fig. 18) is a twin (tandem) turboprop, high-wing craft with twin tail booms, 

capable of carrying up to six passengers or 

equivalent. Gross weight is 2,000 kg ( 4,400 lb). 

The aircraft, marketed in 1965, has been 

adapted for mapping and remote-sensing missions. Remote Sensing, Inc., Houston, Tex., 

reports carrying the following load of remote 

sensors on this aircraft: a Texas Instruments 

RS-310 infrared scanner, an RC-8 or RC-9 

mapping camera, and four gang-mounted Hasselhlad 500 EL multispectral cameras. The 

4-seat version of the aircraft has space for 

equipment weighing 165 kg (365 lb). 

Performance : 

Service ceiling: 8,930 m (29,300 ft). 

Speed: Maximum cruising (75% power) 

is 305 km/h (190 mi/h). Minimum 

or stalling is 113 km/h (70 mi/h). 

Range: At maximum cruising speed 

from 1,900 to 2,500 km (1,190 to 

1,550 mi) with long-range tanks. 

Special equipment: Optional avionics include blind-flying instruments, autopilot, navigation instruments, and an 

oxygen system. 
Beechcraft Queen A,ir.-The Beechcraft 

Queen Air B80 (fig. I9) is a twin-engine, light 

executive or business transport of conventional 

low-wing monoplane configuration. The cabin 

accommodates 6 to II passengers or a crew of 

two on the flight deck with space for sensor 

and electronic equipment. Gross weight is 4,000 

kg (8,800 lb). It is powered by two 380-hp 

Lycoming 6-cylinder horizontally opposed aircooled and supercharged engines. Sensor capacity is 820 kg (I,800 lb). 

Performance : 

Service ceiling: 8,I70 m (26,800 ft). 

Speed: Maximum cruising (70% power) 

is 360 km/h (225 mi/h) at 4,570 m 

(I5,000 ft). 

Range: With maximum fuel and 45-min 

fuel reserve, 2,500 km (I,500 mi). 

Special equipment: The aircraft has a 

deicing system on the leading edge of 

the wings, optional auxiliary fuel 

tanks, a pressurization system, and 

full ground and in-flight air conditioning. 

All Beechcrafts may be equipped with a full 

range of avionics, including dual VHF, radio, 

and elaborate positioning and navigation aids, 

and they may be fitted with vertical mapping 

camera installations. The twin-engine Beechcrafts carry weather-avoidance radar. The King 

Air and Queen Air models may be equipped 

with a wide variety of remote sensors; in I972 

Beech announced the RS99 ("Aviation Week 

and Space Technology," I972) which is a remote-sensing version of the B99 series. 

Grum,man Mohawk.-The Grumman OV-I 

Mohawk (fig. 20) is a high-performance 2-seat 

observation and surveillance aircraft developed 

by Grumman for the U.S. Army. More than 

365 Mohawks have been placed in service in five 

models. The principal difference in the models is 

in the navigation and remote-sensing equipment that has been installed. Some models 

carry a variety of advanced remote-sensing 

equipment, such as the KA-30 high-resolution 

optical photographic system (in model OVIA) and integrated flight systems for day and 

night reconnaissance. 

The aircraft is powered by two I, I60-hp 

Lycoming turboprop engines. Gross weight for 

the OV-IA is 6,820 kg (I5,000 lb). Maximum 

load available for equipment is 2,250 kg ( 5,000 

lb). 

In I97I the U.S. Geological Survey obtained 

a Mohawk Model OV-I for research concerning 

the quality of water and the environment. The 

sensing equipment includes SLAR, a thermal 

scanner, a 230-mm (9-in.) focal-length camera, 

and a cluster of Hasselblad cameras for multispectral photography. This model has a ceiling of about 7,620 m (25,000 ft). 

Performance: 

Service ceiling: (OV-IC) 9,000 m 

(29,500 ft). 

Speed: Maximum cruising (OV-IA) is 

490 km/h (305 mi/h). Minimum or 

stalling (OV-IA) is IIO km/h (68 

mi/h.) 

Range: (OV-IA) 2,260 km (I,400 mi) 

with external tanks, IO% reserve. 

Special equipment: Mohawk models OVIB, OV-IC, and OV-ID carry interchangeable equipment, which includes 

SLAR and an in-flight processor. One 

model, the OV-ID, can be converted 

from infrared reconnaisasnce to 

SLAR surveillance in about 1 hour. 

Lockheed Y0-3A.-Lockheed began studies 

and development on quiet aircraft late in I966. 

The first Lockheed quiet aircraft was the QT2 (Quiet Thruster, 2 seat). The first two prototypes were fitted with night sensors. It is 

reported that reconnaissance flights as low as 

30 m (IOO ft) above ground were made without detection. 

Potential of the quiet reconnaissance type 

of aircraft was recognized, and the U.S. Army 

Aviation Systems Command undertook further development with Lockheed in July I968. 

This resulted in a more refined quiet reconnaissance aircraft, designated Y0-3A (fig. 2I). 

Basis of the design is the Schweizer SGS 2-

32 sailplane, but the new aicraft has a lowwing configuration. The fuselage has been modified extensively. 

Perhaps the greatest single reduction in noise 

has come from using specially developed propellers with three, four, or six blades that rotate 

at speeds as low as 500 r/min. A modified 2IOhp air-cooled Continental 6-cylinder engine provides power. 

IO 
Infrared equipment is carried in the Y0-

3A for night reconnaissance operations. No details on performance are available. 

MEDIUM ALTITUDE, 9 TO 15 KM (29,500-49,000 FT) 

SERVICE CEILING, PROPELLER OR JET 

Rockwell Standard Jet Commander 1121.-

This plane (fig. 22) is a high-speed twin-jet 

executive transport with standard accommodation for a pilot and as many as eight passengers. 

It is powered by two General Electric turbojet engines. Gross weight is 7,640 kg (16,800 

lb) . A stretched version of the Commander is 

known as the Commodore. Production rights 

were taken over by Israeli Aircraft Industries 

in 1967. Sensor capacity is 725 kg (1,600 lb). 

Performance : 

Service ceiling: 13,700 m ( 45,000 ft). 

Speed: Maximum cruising is 805 km/ 

h (500 mi/h) at 10,670 m (35,000 

ft.) Minimum or stalling is 160 km/ 

h (100 mi/h). 

Range: 2,965 km (1,840 mi) with maximum fuel and maximum payload at 

economy cruising speed 760 km/h 

( 470 mi/h) at 11,900 m (39,000 ft), 

no reserve. 

Special equipment: Blind-flying instrumentation is standard. Provision is 

made for full range of radio and radar 

communications, navigation, storm 

warning, glideslope and localizer, and 

Automatic Direction Finding equipment. 

Gates Learjet.-This twin-engine business jet 

(fig. 23) is powered by two General Electric 

CJ610 turbine engines. Designed to carry eight 

passengers, the jet has a gross takeoff weight of 

5,900 kg (13,000 lb). The business jet has 

been modified into a remote-sensing aircraft 

operating for altitudes well above 12,200 m 

(40,000 ft). Sensor capacity is 1,250 kg (2,760 

lb). 

First marketed in 1966, the Learjet 24 replaced the earlier Model 23. 

Performance (Gates Learjet 24) : 

Service ceiling: 13,700 m ( 45,000 ft). 

Speed : Maximum airspeed, Mach 0.81 

at 9,450 m (31,000 ft) or 885 km/ 

h ( 550 mi/h) . Normal cruise speed, 

Mach 0.77 at 12,500 m (41,000 ft) or 

820 km/h (510 mi/h). Stalling speed 

at sea level with 4,090 kg (9,000 lb) , 

landing configuration, is 155 km/h 

(96 mi/h). 

Range : 2,400 km ( 1,500 mi) with 8 

passengers, 45-min fuel reserve. 

Special equipment: Figure 23 shows a 

Gates Learj et 24, the model most extensively used in remote sensing, with 

the special door open to show the 

camera installation. 

Several domestic and foreign companies have 

built modifications to the Learjet door to allow 

cameras inside the pressurized cabin to photograph through an optical glass plate in the floor 

of the special door. A quick-change modification to the door allows the jet to be taken off 

charter service for camera work and returned 

to passenger hauling. The conversion takes 

about 3 hours. 

An earlier Learjet Model 23 was used by 

astronomers of Rice University, Houston, Tex., 

in the research project "Flying Infrared Telescope," operating on top of the troposphere, at 

altitudes of 15,200 m ( 50,000 ft) to photograph 

the stars, planets, and planetary nebulas. The 

Learj et was provided by NASA Ames Research 

Center (Hudson, 1968 and 1971). 

Fairchild Hiller Porter.-This is a versatile 

airplane (fig. 24) designed to fill a wide variety 

of aerial sensing needs. It has an extremely 

short take off of 90 m (300 ft) and a landing 

distance of less than 45 m (150ft). The Porter 

carries as many as 11 passengers, or it can 

carry a remote-sensor package weighing 910 

kg (2,000 lb). It has a small but powerful 

turbine engine and reversible propeller. Additional fuel may be carried in external wingmounted pylons and would extend the plane's 

range to a thousand miles. Its gross weight is 

2,200 kg ( 4,850 lb). 

11 

Performance : 

Service ceiling: 7,770 m (25,500 ft). 

Speed: Maximum cruising at 3,050-3,650 

m (10,000-12,000 ft) is 280 km/h 

(175 mi/h). 

Range: 970 km ( 600 mi) with normal 

configuration and maximum fuel; 

1,600 km (1,000 mi) with external 

wing-mounted tanks. 
Special equipment: The Porter can be 

adapted for aerial photography and 

other remote sensing. A military version carries a complete radio communications s~stem, a pod containing 

three P-2 70-mm cameras, and 40 

flares of 2 million candlepower for 

night photographs. It has a floor hatch 

and large cargo doors for installing 

special sensing equipment. 

Lockheed NP3A Orion.-This aircraft (fig. 

25) , which was derived from the Electra, is a 

4-engine turboprop low-wing plane capable of 

carrying a sensor payload of as much as 9,000 

kg (20,000 lb). Maximum gross weight is 

51,400 kg (113,000 lb). NASA 927 is such a 

craft adapted for remote-sensor research. The 

"Annual Report, 1971," of NASA Manned 

Spacecraft Center, Earth Observation Aircraft 

Program, describes this aircraft and the sensors in considerable detail. The total sensorrelated equipment weighs 2,500 kg (5,500 lb) 

as configured in this aircraft. 

Performance : 

Service ceiling: 9,100 m (30,000 ft). 

Speed: Maximum cruising is 610 km/h 

(330 kn). Minimum or stalling is 280 

km/h (150 kn). 

Range: 3,700 to 3,900 km (2,300 to 2,400 

mi). 

Endurance : 7 h. 

Stability: Extent of average deviations 

from prescribed attitude is ±2° in 

pitch and roll and ±8° in yaw. 

Special equipment: Precise altimeter, 

Loran navigation system, inertial 

navigation unit, gyro-stabilized platform. 

Douglas Skywarrior RA-3B.-Production of 

the twin-jet RA-3B (fig. 26) carrier-based aircraft ended in January 1961, and only four 

remain in service with the U.S. Navy late in 

1973. Nevertheless, they are a major element 

of the U.S. Navy reconnaissance and mapping 

effort and are effective, versatile, and durable. 

The RA-3B photographic reconnaissance aircraft are versions of the standard McDonnell 

Douglas A-3 airframe. Weight empty is 19,800 

kg ( 43,500 lb) ; normal loaded weight is 35,500 

kg (78,000 lb) ; and overload weight is 37,300 

kg (82,000 lb). 

Performance : 

Service ceiling: 13,700 m (45,000 ft). 

Speed: Maximum cruising 1,020 km/h 

(630 mi/h) at 9,150 km (30,000 ft) 

altitude. Landing speed 269 km/h 

(167 mi/h). 

Normal range: More than 4,650 km 

(2,880 mi). 

Endurance: 5 h, plus 15 h with in-flight 

refueling capability. 

Special equipment: This aircraft has 16 

camera windows and sufficient space 

and lifting capacity to carry a wide 

array of sensors (Barton, 1972). As 

many as 12 cameras ranging from 45 

to 910 mm (1.75 to 36 in.) are carried simultaneously. Night photography supported by flares, infrared 

scanning, and radar imaging can also 

be carried out. A dual viewfinder system also supports the remote-sensing 

mission. 

Additional information on special equipment 

is given in "RA-3B Photographic Capabilities 

Handbook," published by the U.S. Navy, Fleet 

Air Reconnaissance Squadron ONE. 

Lockheed NC130B (RC130) .-This plane 

(fig. 27) is used as a NASA sensor system facility, which carries both imaging and nonimaging remote sensors. The data acquisition system includes various onboard remote sensors, 

signal processing, and a control and recording 

system. The Lockheed NC130B is an all-metal 

high-wing long-range land-based monoplane 

powered by four Allison turboprop constantspeed engines. The fuselage can be pressurized 

and airconditioned in flight and on the ground. 

The military photomapping version has the 

principal mission of executing electronic aerial 

geodetic surveying and photogrammetric mapping in an integrated system. Gross weight is 

61,400 kg (135,000 lb). Weight available for 

sensor payload is 9,230 kg (20,300 lb). 

Performance : 

Service ceiling: 10,700 m (35,000 ft). 

Speed: Maximum cruising is 590 km/h 

(320 kn). 

Range: 4,000 km (2,500 mi). 

Endurance: 9 h. 

Stability: Extent of average deviations 

12 
from prescribed attitude is ±21f2 o in 

pitch, +7° in roll, and +5° in yaw. 

Special equipment: In NASA's version, 

each of the four camera windows accommodates the field of view of an 

R.C-8 metric camera plus allowance 

for roll stabilization of up to +6°. 

The TV subsystem is used by the pilot 

in following a ground track. N avigation subsystems include an inertial 

navigation system, a radar altimeter 

set, a navigational computer, and remote navigation indicators. Aircraft 

position in latitude and longitude coordinates is displayed at the navigator's station. SLAR is boresighted 

with a cam.era window. Military 

photomapping versions carry a similar 

array of special equipment which supports basic mapping functions. 

Boeing Stratolifter (RC135A).-This plane 

is a long-range jet transport developed from 

the KC135A Stratotanker. The KC135A aircraft were powered by Pratt and Whitney turbojet engines and became the first strategic 

jet transports in the Military Air Transport 

Service (MATS). All KC135 aircraft are similar to but smaller than the Boeing 707 airliner, 

both derived from the 707 prototype (figs. 28, 

29). 

Four RC135A aircraft were built. They were 

similar to the KC135A but specially equipped 

for multiple cameras and electronic equipment 

for photomapping and electronic surveying of 

the terrain, using SHIRAN, an electronic system for establishing geodetic control. However, 

the cost of upkeep for photomapping could not 

be justified, and the four RC135A photomapping aircraft were converted from photomapping to other uses during 1972. Ten aircraft 

designated WC135B (same as C135·B) were 

modified for long-range weather reconnaissance 

missions for the Military Airlift Command 

(MAC), Air Weather Service. Other Air Force 

reconnaissance versions include the RC135B 

and RC135D. Gross weight (C135B) is 125,000 

kg (275,500 lb). 

Performance : 

Service ceiling: 9,100 to 13,700 m 

(30,000 to 45,000 ft). 

Speed: Average cruising speed 855 km/ 

h (530 mi/h) at 10,700 m (35,000 ft). 

Maximum level speed 970 km/h (600 

mi/h). 

Range: 7,400 km ( 4,600 mi) with 24,500 

kg (54,000 lb) payload. Maximum 

ferry range is 14,485 km (9,000 mi). 

Special equipment: The RC135A carries special navigation equipment for 

improved mapping accuracy. The aircraft were assigned to the 1370th 

Photo Mapping Wing of the MAC. 

The mapping system was known as 

the AN /USQ 28 and was probably the 

most sophisticated ever built. 

E-Systems (formerly LTV) L450F reconnaissance aircraft.-This is a motorized version of the Schweizer sailplane built to meet 

military aircraft requirements for high-altitude and endurance (fig. 30). It is powered by 

a modified Pratt and Whitney turboprop engine. The new design provides the capability of 

carrying data-gathering or electronic relay 

equipment similar to that of a communications 

satellite. The relay equipment can be carried 

to an altitude of 13,700 m (45,000 ft) and 

could be operated up to 24 h at a time. Alternatively, the aircraft can be flown unmanned 

by remote control over a radius of 400 km 

(250 mi). 

For operation in the unmanned mode, automatic stabilization equipment is installed, and 

complete ground control and monitoring by 

telemetry allows control of the aircraft in a 

variety of modes. Gross weight is 2,140 kg 

(4,700 lb). Payload is 160 to 320 kg (350 to 

700lb). 

13 

Performance: 

Service ceiling : 13,700 to 15,200 m 

(45,000 to 50,000 ft). 

Speed: Maximum cruising at 13,700 m 

(45,000 ft) is 170 km/h (105 mi/h). 

Best glide ratio: 28:1. 

Range (piloted version) : 9,700 km 

(6,000 mi). 

Endurance: 24 'to 30 h. 

HIGH ALTITUDE, SERVICE CEILING ABOVE 15 KM 

(49,000 FT) 

North American Rockwell X15.-This plane 

(fig. 31) was a highly specialized research ve-
hicle jointly funded by the Air Force, the Navy, 

and the National Aeronautics and Space Administration (Aerospace Industries Assoc., 

1970). Three aircraft were built, with the first 

flight on June 8, 1959. Tests conducted on this 

unique platform contributed to research, particularly in studies related to hypersonic and 

hyperaltitude flight regimes. It attained speeds 

greater than Mach 6 and altitudes above 107,-

000 m (350,000 ft). The No. 1 plane, now in 

the Smithsonian Institution, was used for research in high-altitude aerial photography, 

ultraviolet stellar photography, atmospheric 

density measurements, horizon scanning and 

definition measurements, and advanced integrated data systems. It was also used in research to determine the effects of flight regimes 

covering a wide range of speeds, altitudes, and 

environmental conditions on photographic film 

resolution and distortion. The No. 2 plane, 

shown in figure 31, was fitted with twin droppable fuel tanks, coated with ablative material, and modified as a ramjet test bed. It was 

the plane which set an unofficial speed record 

of Mach 6. 7 or 7,290 km/h ( 4,520 mi/h) . The 

No. 3 aircraft was destroyed in an accident on 

Nov. 11, 1967, in which Major M. J. Adams 

lost his life. The three X15's made 197 flights 

in 10 years. 

Performance: 

Maximum altitude: 108,000 m (354,200 

ft or 67.1 mi) reached by Joseph 

Walker, chief test pilot, NASA, on 

Aug. 22, 1963. 

Speed: An official speed record was 

achieved by Joseph Walker, on June 

27, 1962, at 6,620 km/h ( 4,104 mi/h). 

An unofficial speed was recorded at 

7,290 km/h (4,520 mi/h) on Nov. 18, 

1966, by Major Pete Knight, USAF. 

Total flight life of aircraft: Approximately 24 h. 

Maximum launching weight: 23,140 kg 

(50,900 lb). 

Maximum landing weight: 7,780 kg 

(17,120 lb). 

Payload: Instrumentation payload designed for the X15A was 590 kg 

(1,300 lb). 

Special equipment: Research was undertaken to determine the effects of highspeed shock waves and friction-heated 

air turbulence on aerial photographs 

taken from a camera mounted in the 

nose of the aircraft. Among the 

cameras flown was an experimental 

type KC-1 camera body fitted with a 

prototype lens, forerunner of the 152-

mm (6-in.) focal length f/5.6 Geocon 

I designed by Dr. James Baker. This 

camera was installed in an ART-15 

gyrostabilized mount in the pressurized instrument compartment just aft 

of the cockpit. A special quartz glass, 

nearly optically flat and 460 mm ( 18 

in.) in diameter, was used for the 

window. Six flights were made to determine geometric image deformations produced by high-altitude supersonic flight. 

Another series of flights was conducted to 

determine image-resolution degradation using 

an experimental KS-25 camera with a 610-mm 

(24-in.) focal length lens developed by the Air 

Force Avionics Laboratory at Wright-Patterson AFB, Ohio. This camera was capable of 

resolving better than 115 lines per millimeter on 

fine-grain photographic film. It was installed 

in the same ART-15 mount that has been used 

to carry the KC-1 mapping camera. One objective of this test was to obtain photographic 

images that would, as nearly as possible, simulate those that were expected to be obtained 

later from space. Photographs obtained with 

the X15 thus permitted comparative studies 

and interpretation which paved the way for 

analysis and evaluation of high-altitude aircraft and space photography which was to 

follow. 

In another experiment, a gimbal-mounted 4-

camera platform was used for research in ultraviolet steller photography and for photographing the stars from altitudes above 65 km 

(40 mi). 

A horizon scanner was also used to study the 

light spectrum of the sky and to obtain data on 

the accuracy of sensing the horizon. These data 

were later used to improve attitude and guidance references for Earth-orbiting spacecraft. 

14 
General Dynamics/Martin RB57F (WB57F). 

-A General Dynamics/Martin WB57F aircraft is flown and maintained for the NASA 

Earth Observations Aircraft Program Office. 

The WB57F shown in figure 32 is a midwing 

4-engine aircraft powered by two Pratt and 

Whitney turbofan engines and two auxiliary removable Pratt and Whitney turbojets carried 

in underwing pods. 

The data acquisition system comprises an 

airborne sensor platform, various sensors, and 

ancillary control and data-recording equipment. 

The sensor equipment is described in detail in 

the "Annual Report, 1971," of the NASA 

Manned Spacecraft Center, Earth Observation 

Aircraft Program. Gross weight is 28,600 kg 

( 63,000 lb) . Estimated weight available for 

remote-sensor payload is 2,160 kg (4,750 lb). 

Performance: 

Service ceiling: 18,900 m (62,000 ft). 

Speed : Maximum cruising at 18,300 m 

(60,000 ft) is 740 km/h (460 mi/h). 

Minimum or stalling is 145 km/h (90 

mi/h). 

Range: 5,320 km (3,300 mi). 

Endurance: +4 hat service ceiling. 

Stability: Extent of average deviations 

from prescribed attitude is approximately +0.5° in pitch and roll and 

+8° in yaw. 

Special equipment: Considerable special 

equipment is c a r r i e d , including 

weather radar in the fuselage nose, an 

autopilot, and a navigation system 

comprising a C-12 Gyrosyn compass, 

an APN-102 Doppler radar, and an 

ASN-41A navigator computer. A 

Litton LTN-51 inertial navigation 

system was added in 1972. The system measures the heading, ground 

speed, and drift angle of the aircraft, 

and computes present latitude and 

longitude, distance to destination, 

ground track, and relative bearing. An 

APN-159 pulse-type radar altimeter 

indicates absolute clearance of the aircraft above the terrain. An optical 

viewfinder enables the equipment operator to view the terrain ahead of 

the aircraft and to measure drift. A 

multispectral scanning imaging spectroradiometer was installed in 1972. 

McDonnell Douglas RF-4C.-This high-performance fighter-type aircraft (F-4) (figs. 33, 

34) is modified for multiple-sensor reconnaissance. It incorporates optical, infrared, and 

electronic sensors for reconnaissance missions 

day or night and in any kind of weather. Its optical systems include a num.ber of cameras of 

various focal lengths, forward- and side-looking cameras, and panoramic cameras that scan 

the terrain from horizon to horizon. Films can 

be processed in flight and ejected over the 

ground command station. The RF -4C also carries side-looking radar for mapping on each 

side of the flight path and a third radar for 

forward-looking ground mapping. It also carries an infrared sensor for day or night use. 

Gross weight is 24,800 kg (54,600 lb). 

Performance : 

Service ceiling: 15,200 m (50,000 ft). 

However, the F-4B version has temporarily reached 30,000 m (98,400 ft) 

in a time-to-height test which took 

slightly over 6 min to achieve. 

Speed: Maximum cruising 2,240 km/h 

(1,390 mi/h) at 12,200 m (40,000 ft). 

Range: Ferry range, 3,700 km (2,300 

mi). 

Special equipment: Navigation radar 

including terrain avoidance, central 

air data computer, navigational computer, and electronic altimeter. 

Lockheed U-2.-This unique aircraft (fig. 

35) is capable of sustained flight at very high 

altitudes. Although basically a manned aircraft, 

recent reports ("Aviation Week and Space 

Technology," 1971) indicate the U-2 has also 

been converted into a drone. In April 1971, 

NASA acquired on loan from the U.S. Air 

Force two U-2 aircraft for high-altitude 

photography and research. Gross weight is 

7,850 kg (17,270 lb) with external tanks. 

The primary job of the NASA U-2 aircraft 

is to complement two Earth resources research 

space flights: the Earth Resources Technology 

Satellite (ERTS) and the manned orbital workshop, Skylab. Test sites were photographed and 

analyzed before the launch of the spacecraft, 

and the U-2's photographed sites simultaneously with the passes of both ERTS and Skylab 

in 1972 and 1973. 

15 
Performance : 

Service ceiling: 21,300 m (70,000 ft). 

Speed : Maxim urn cruising is 790 km/h 

(490 mi/h). 

Range: Internal fuel only, 100 U.S. gal 

reserve, 3,550 km (2,200 mi); with 

external tanks, 100 U.S. gal reserve, 

4,200 km ( 2, 600 mi) . 

Endurance: Approximately 5 h. 

Stability: The U-2 at high altitude is 

highly stable as demonstrated by continuous strips of near-vertical mapping photographs which show no signs 

of vibration or longer term oscillations even though a stabilizing mount 

was not used. 

Special equipment: The Air Force carried a variety of frame and panoramic 

cameras of up to 610 mm (24 in.) 

focal length. These include mapping 

cameras in gyrostabilized mounts. 

NASA uses a gang of small multispectral cameras to simulate space 

imagery and also carries a mapping 

camera of 152 mm (6 in.) focal length. 

A ventral periscopic sight or viewfinder is included, and an autopilot 

has also been installed on occasions. 

In late 1973, NASA plans to install at 

least one inertial guidance system. 

Lockheed SR71 (YF-12) .-The Lockheed 

SR71 (fig. 36) is an Air Force long-range advanced strategic reconnaissance aircraft. One 

of the fastest and highest flying aircraft in the 

world, it is capable of worldwide reconnaissance 

operations including aerial photographic missions and multiple forms of remote sensing. It 

is powered by two Pratt and Whitney J58 turbojets and has a speed of Mach 3, or more than 

3,400 km/h (2,100 mi/h). The SR71 is the 

reconnaissance version of the general YF -12 

series of aircraft. However, the reconnaissance 

version is the only one in operational use today. 

Gross weight is 76,500 kg (170,000 lb). 

Performance: 

Service ceiling: Over 24,400 m (80,000 

ft) ; maximum ceiling reported at 36,-

600 m (120,000 ft). 

Speed: Maximum 3,340 km/h (2,070 mil 

h) at 24,463 m (80,258 ft) a world 

record, May 1, 1965. Minimum or stalling not given. 

Range: More than 3,220 km (2,000 mi) ; 

with aerial refueling it has global 

range. 

Special equipment: Equipment ranges 

from simple surveillance to multiplesensor high-performance reconnaissance systems. 

BELL HELICOPTER 47G-3B-l 

The Bell 47G-3B-1 helicopter is utilized by 

the U.S. Department of Agriculture, Forest 

Service, Northern Forest Fire Laboratory, Missoula, Mont., as a platform for a simple infrared line scanner. The Forest Service Fire 8potter can be used to locate forest fires that are 

too small to be readily visible to optical detection system. Nominal altitude is 610 m (2,000 

ft). Gross weight for the model 47G-3B-:1 

shown in figure 37 is 1,340 kg (2,950 lb). Th1s 

model is a 3-seater with high-altitude performance over a wide range of temperatures. This 

helicopter is powered by a supercharged Lycoming engine uprated to 280 hp. 

During 1973, the Forest Service was experimenting with a telemetry near-real-time system 

as compared with the conventional infrared line 

scanner from which the data must be physically 

returned and processed before evaluation. With 

the telemetry system the imagery data are 

transmitted from the helicopter to the ground 

station where evaluation can start immediately. 

Performance: 

Service ceiling: 4,270 m (14,000 ft). 

Speed: Maximum 170 km/h (105 mi/h) 

at sea level. Cruising 135 km/h (83 

mi/h) at 1,520 m (5,000 ft). 

Range: 400 km (250 mi) with maximum 

fuel at 1,520 m (5,000 ft) and no 

reserves. 

Endurance: Approximately 3 h. 

Maximum payload: 540 kg (1,190 lb). 

NORTHROP FALCONER DRONE 

This surveillance drone (see also E-Systems, 

p. 13) (fig. 38) was developed originally for the 

U.S. Army Signal Corps. Launched from a zerolength launcher, it is controlled remotely by 

16 
radio and tracked by radar. It carries still or 

TV cameras for surveillance over hostile territory. On reaching a predetermined recovery 

area the controller commands parachute recovery. The camera is removed, the film is 

processed, and the prints are delivered within 

minutes after recovery. Models are available 

for day or night photointelligence and reconnaissance duties. The cameras can be replaced 

by other sensor systems. This propeller-driven 

platform is powered by a 9-2-hp McCulloch aircooled engine. Maximum launching weight is 

200 kg (440 lb). Empty weight is 160 kg (350 

lb). 

Performance: 

Service ceiling: 4,570 m ( 15,000 ft). 

Speed: Maximum level speed at sea level 

is 320 km/h (201 mi/h). 

Endurance at sea level: 35 min. 

Special equipment: Recovery is by a 

single-stage 13.4 m ( 44 ft) extendedskirt parachute deployed on command 

or automatically. The radio-command 

flight-control system includes a receiver autopilot. Special equipment includes two 75-mm cameras, a flare 

ejector, a radar beacon or passive 

radar reflector pods, and a night light 

identification system. Flares are carried for night photography. 

GOODYEAR BLIMPS 

The blimps Columbia, America, and Mayflower, owned and operated by the Goodyear 

Tire and Rubber Company, Akron, Ohio, are 

the only lighter-than-air craft known to be 

operating in the U.S. today. They were built 

during the period 1968-1971. The three aircraft are the 297th, 298th, and 299th blimps 

that the company has built since 1917, mostly 

for the U.S. Army or Navy. Power is supplied 

by twin 6-cylinder pusher-type 210-hp Continental engines (figs. 39, 40). 

The three blimps are in demand by the news 

media, particularly television networks, for use 

as aerial and television camera platforms for 

viewing special events. Their aerial photographs have appeared in virtually every newspaper and magazine. 

Performance: 

Service ceiling: Maximum 2,290 m 

(7,500 ft). Normal operational altitude 300 to 910 m (1,000 to 3,000 ft). 

Speed: Maximum 80 km/h (50 mi/h). 

Cruising 55 km/h ( 35 mi/h) . 

Size: Columbia 58.5 m ( 192 ft) long, 18 

m (59.5 ft) high, 15m (50ft) wide. 

Volume: Columbia, 5,800 m3 (202,700 

fV). 

Weight: Maximum gross 5,600 kg 

(12,320 lb) ; empty 4,100 kg (9,040 

lb). 

Maximum lift or payload: 1,490 kg 

(3,280 lb) or six passengers plus pilot. 

Range : 805 km ( 500 mi) . 

Endurance: 20 h. 

Special equipment: The blimp carries 

special TV orthicon viewing cameras 

for aerial scenes and transmits the 

data to a ground-crew bus which 

serves as radio headquarters. It also 

carries frame and movie cameras and 

broadcasting equipment for reporting 

special :events. 

A recent report by the Aero-Mechanical Programs of the Goodyear Aerospace Corp. (1971) 

describes the use of airborne sensing equipment 

flown aboard a Goodyear blimp, including isolated nose-probe acoustic sensor, steerable 

acoustic sensor, stereo acoustic sensors, directional acoustic sensor, remotely controlled TV 

camera, infrared covert illuminator, acoustic 

gradient array, low-light-level and daytime TV, 

remote trailing sensor, and an aft-looking 

sensor. 

Test equipment can be located virtually anywhere on the airship. Acoustic and infrared 

sensors can be isolated from engine noise and 

heat. Sensors can be lowered or dunked from 

the airship into hard-to-reach places. 

Acceleration in the cabin of the aircraft during powered flight is less than l/40th g (acceleration of gravity) with a vibration frequency 

range of 10 to 1,000 Hz. 

There is no indication that blimps are being 

used for remote sensing except for their news 

media role. 

SCHWEIZER SAILPLANE SGS 2-32 

The Schweizer sailplane SGS 2-32 has an 

unusually large airplane-type cabin capable of 

17 
carrying two average-sized passengers in addition to the pilot (fig. 41). It has an all-metal 

monocoque structure, and the airframe has been 

used as a basis for several powered aircraft. 

The SGS 2-32 was chosen by Lockheed Missiles 

and Space Company to form the basic airframe 

of its Y0-3A quiet reconnaissance aircraft and 

by Ling-Temco-Vought (now E-Systems) for 

its L450F. The sailplane's maximum takeoff 

gross weight is 610 kg (1,340 lb). 

Performance: 

Speed: Maximum (smooth air) 225 km/ 

h (140 mi/h). Minimum or stalling 

77 km/h ( 48 mi/h). Minimum sinking 

speed 0.7 m/s (2.4 ft/s) at 80 km/h 

(50 mi/h). 

Best glide ratio: 34: 1 at 97 km/h ( 60 

mi/h). 

Maximum aero-tow speed: 180 km/h 

(110 mi/h). 

Special equipment: Optional equipment 

includes electrical and oxygen systems, 

radio communications, and such special instrumentation as might be specified, including provisions for aerial 

cameras or other remote sensors. 

SPACECRAFT 

With the advent of space systems, a new 

dimension has been added to remote sensing. 

Platforms are no longer limited by the atmosphere, and orbits can be defined which provide 

the following: (1) Any altitude desired as long 

as it is effectively above that of atmospheric 

drag effects (about 150 km) and still within the 

dominant gravity field of the Earth. (2) Configuration so that the entire Earth or any designated portion can be covered at specified 

intervals. (3) Constant position relative to the 

Earth's surface through the geostationary 

mode, thus permitting continuous sensing of a 

given section of the Earth's surface. ( 4) Remote 

sensing at relatively close range of extraterrestrial bodies such as the Moon and planets 

and without the interference of the Earth's 

atmosphere. 

Remote sensing of the entire Earth on a 

periodic basis and sizable sections on a continuous basis thus becomes feasible. Lighting and 

atmospheric conditions will limit the effectiveness of the system particularly where sensing 

of the actual surface with reflected solar energy is involved. The meteorological satellites 

demonstrate the Earth-sensing electronic transmission space modes even though they do not 

carry sensors that resolve the surface to the 

extent desired for many applications associated 

with Earth studies. 

Satellites designed for remote sensing on an 

operational basis are generally unmanned 

though manned space stations provide similar 

capabilities. Manned extraterrestrial missions, 

such as Apollo, can provide opportunities for 

remote sensing of the Moon or planet concerned; however, to date manned missions have 

not been defined with remote sensing as their 

primary objective. 

GENERAL CONSIDERATIONS 

No attempt is made to cover either the theory 

or the state-of-the-art of space flights. The 

problems of achieving and maintaining the 

proper orbit and providing the power and environment for remote sensing are beyond the 

scope of this circular. However, the problems 

of data transmission and spacecraft platform 

stability are unique to remote-sensing missions 

and are therefore briefly covered. Information 

in this section has been obtained from "Jane's 

All the World's Aircraft" unless otherwise 

noted. 

DATA TRANSMISSION 

All space flights require a network of ground 

control stations for data transmission and command of the spacecraft. These networks vary 

with the type of mission. The NASA network 

for Earth and lunar missions is described in the 

"Space Tracking and Data Acquisition Network 

Manual" (NASA, 1967). The transmission and 

control network for planetary flights is described in "The Deep Space Network" (Calif. 

Inst. of Tech., Jet Propulsion Laboratory, 

1971). 

The NOAA system for its operational 

meteorological satellites is described in the 

"Instructions and Operating Handbook for the 

Improved TIROS Operational System (IT OS) 

and the TIROS Operational System (TOS), 

Part 4." 

18 
Except for the film return mode, as exemplified by manned missions, sensor response must 

be in electronic signal form and transmitted to 

Earth. If this is to be done globally on a realtime basis, from Earth-sensing systems such as 

the meteorological satellites, there must be a 

ground station network capable of continuously 

receiving from the satellite. Since the wavelengths involved require line-of-sight transmission, several ground stations, depending on the 

orbit, are needed to acquire the data. The use of 

geostationary communications satellites as relay stations is a recent development which 

promises to simplify the data-transmission 

problem and reduce the number of ground stations required. Three U.S. ground stations are 

employed for the Earth Resources Technology 

Satellite . (ERTS-1) data acquisition. Canadians installed a ground station prior to launch, 

Brazil installed a ground station during 1973; 

and other countries have asked for advice in 

setting up similar installations. For areas outside the ground stations' range, a wide-band 

video tape recorder is included on ERTS-1 

which stores the data on board and then plays 

it back when the flight is within range of a 

ground station. This procedure precludes realtime transmission, but the delay involved in 

transmission will generally be less than 1 hour. 

It is important to note, however, that data 

processing of ERTS is centralized, and therefore additional delay generally occurs prior to 

actual receipt of the data by the processing 

center at Greenbelt, Md. Early in 1973, ERTS-1 

lost part of the use of its second tape recorder 

(the first failed shortly after launch), thus 

reducing its coverage beyond the range of the 

ground stations. The problem of recovering 

hard copy, such as film, is discussed briefly under film return (p. 20). During 1973 this mode 

was being demonstrated by Skylab. 

PLATFORM STABILITY 

In theory, a spacecraft might be free of all 

relative motion except for its designed orbital 

vector, and thus be a perfectly stabilized platform. In practice, spacecraft must be controlled 

to maintain proper attitude and to dampen inevitable oscillations, including vibrations that 

may develop from onboard mechanisms. Attitude must he sensed and determined before it 

can be adjusted. Horizon sensors, particularly 

in the infrared region, can relate spacecraft 

attitude to the Earth or another planet as a 

whole, but there are limits to this procedure, 

which is accurate only to the order of a tenth 

of a degree. Truly precise attitude can he obtained by stellar observations. This approach 

is used on extraterrestrial flights and has also 

been defined for film-return Earth-sensing missions. The control of attitude can be accomplished by reaction jets, gim·baled inertial systems (including gyros), torquing with respect 

to the Earth's magnetic field, or even a gravity 

gradient boom which works on the principle 

that a linear-shaped mass will aline itself in a 

gravitational field. To keep from constantly correcting for attitude, some limits or deadbands 

are imposed before corrective action is introduced. The fewer the corrections, the more 

stable and longer lived the platform's attitude 

control system, and thus reduction of rotational 

rates (damping) is a desirable objective. Some 

figures relative to deadbands and rotational 

rates are quoted for described spacecraft. 

Station keeping, which involves adjustment 

by jet thrusters, is another source of instability. 

On remote-sensing missions it is more desirable 

to allow the orbit to change somewhat rather 

than pay the price of constant station keeping. 

Although there is no such thing as a fully stable 

Earth orbit, some spacecraft have remained in 

the same nominal Earth orbit for several years 

without station-keeping adjustment. 

DESCRIPTIONS OF SPACECRAFT 

The spacecraft section is divided into two 

parts. The first covers experimental spacecraft, 

which are flown by NASA, and the second 

covers operational remote-sensing· spaceGraft, 

which are flown by NOAA. 

EXPERIMENTAL, UNMANNED, EARTH VIEWING 

Three basic unmanned space modes for sensing the Earth have been defined : 

(1) Film return, short-lived, 150-500 km 

altitude, sun-synchronous. 

(2) Electronic data transmission, long-lived, 

300-1,500 km altitude, sun-synchronous, except 

19 
for TIROS 1-8: (TIROS, ITOS, Nimbus, 

ERTS-A&B) 1 

(3) Electronic data transmission, long-lived, 

36,000 km altitude,· geostationary or geosynchronous : Advanced Technology Satellite 

(A TS) , Synchronous Meteorological Satellite 

( SMS) , and the proposed Synchronous Earth 

Observation Satellite (SEOS). 

FILM RETURN 

The NASA manned spacecraft program has 

repeatedly returned exposed film to Earth ; 

however, an unmanned film-return mission has 

not been flown by NASA except as incident to 

the manned program (Apollo 6). Unmanned 

film-return missions have been defined and requested of NASA by the U.S. Department of 

the Interior (1970). 

Newspapers, periodicals such as "Space Business Daily" (1971) and "Science News" (Driscoll, 1971), and a recent book by Klass (1971) 

refer to so-called reconnaissance/ surveillance 

satellites of the film-return type. Jane's describes United States SAMOS and U.S.S.R. 

COSMOS surveillance satellites in general 

terms, but official information relative to the 

remote-sensing capabilities of such satellites is 

not available. The "Aeronautics and Space Report of the President for 1970" (1971) tabulates basic data on all United States space 

flights. The semiannual publication "Rockets 

and Satellites Catalogue of Data" by the World 

Data Center A ( 1971) tabulates worldwide 

data on space flights. Surveillance space flights 

would be tabulated in these publications. 

Although no unmanned platform designed for 

film return is specially described, figure 42 illustrates the configuration that such a vehicle 

might take. General Electric Company· ( 1967b) 

and Lockheed Missiles and Space Co. ( 1967 and 

1969) have both described film-return missions. 

The U.S. Department of the Interior proposal 

( 1970) of such a mission to NASA did not 

designate the vehicle but did include the following specifications: 

Target date: 1972. 

Orbit: 232 km altitude, circular, 83° inclina1 Designation of NASA programs that exemplify the 

mode. 

tion to Equator, sun synchronous, 10:00 

a.m. local time for photographic limb. 

Design life: 30 to 40 days. 

Cameras: 2 metric, 305-mm focal length with 

240-mm (9.5-in.) film width. 

A pair of stellar cameras are included for 

attitude determination, and the entire payload 

weight would be in the order of 1,000 kg. NASA 

has sponsored the design of a laser altimeter for 

such a satellite, and Doppler transponders 

which would provide precise location are currently used on navigation satellites such as the 

Navy's Tranet. 

On film-return flights, exposed film is stored 

on board, and at a prescribed interval or at the 

end of the mission a reentry vehicle, with the 

film, is detached on a signaled command. A propulsion unit reduces the velocity of the reentry 

vehicle so that it reenters the atmosphere, 

where a parachute further reduces its rate of 

fall. Aircraft with grappling lines snag the 

chute lines, and the reentry vehicle is brought 

on board the aircr~Jt. NASA has demonstrated 

this procedure by recovery of its biosatellite 

(TRW, 1969). ThE recovery operation is illustrated in figure 43. 

For such remote-sensing missions, onboard 

data recording to correlate images with precise 

time, and thus position, is essential. Attitude 

controls and determination are also needed. The 

cameras must be command controlled, with 

flexibility such as exposure variations being 

highly desirable. Since film will fog due to radiation, it must be shielded. Indications are that 

the practical lifetime is something less than a 

year. Obviously the film-return mode involves 

high cost since cameras are not recovered from 

their limited-life mission, as now defined, and 

the film recovery operation requires elaborate 

logistical support. 

ELECTRONIC DATA TRANSMISSION, GENERALLY 

SUN SYNCHRONOUS 

This mode includes NASA and NOAA meteorological satellites and also the first Earth 

Resources Technology Satellite (ER.TS-1), 

which was launched July 23, 1972. The relationship of experimental to operational meteorological satellites is shown in figures 68, 69. Such 

20 
spacecraft, except for the early TIROS (1-8), 

are launched into near-polar circular orbits, 

which retain a fixed relationship with respect 

to the Sun-Earth axis. At any given position on 

the orbit, local Sun time will be the same, thus 

creating the sun-synchronous condition. As the 

Sun latitude changes with the seasons the Sun 

elevation on any given earth surface scene will 

also change, but the Sun longitude (time) will 

be basically fixed whenever the spacecraft 

passes over the same scene. 

Altitudes of such orbits are in the order to 

300 to 1,500 km. Since the flight is long lived, 

the orbit must be completely above atmospheric 

drag effects. The field of view of the sensors 

and the density and capability of the ground stations to which all data must be transmitted further define the orbit. Meteorological spacecraft, 

in near polar orbit, can effectively sense the 

entire Earth every 24 hours during daylight 

and every 12 hours when equipped with both 

day and night sensors. In a high-resolution system, such as ERTS, the field of view of the 

sensor is small and even at its 920-km altitude 

it will take 18 days to completely image the 

Earth during daylight hours, except for the 

poles, which are riot covered due to the orbital 

inclination. To date, 5 Nimbus, 10 TIROS, 9 

TOS, 1 ITOS, and 1 ERTS have been successfully orbited. These are described in chronological order, and TOS and ITOS are described 

as operational (NOAA) satellites. 

Nimbus.-The Nimbus program, started in 

1958 and still continuing, was conceived as a 

test bed for spaceborne remote-sensing instrumentation. Six launches have been made; five 

were successful. Although primarily meteorological, Nimbus has been utilized successfully 

to test application of instrumentation on a 

broad scale of Earth-observing usage, and a 

further launch is scheduled for 1974 (fig. 44). 

Description (Nimbus D) : 

Size (overall in-orbit dimensions) 2.9 m 

(9.5 ft) high, 2.9 m (9.5 ft) wide, 

sensor ring 1.47 m (4.82 ft) x 0.33 m 

(1.08 ft). 

Weight: 570 kg (1,260 lb). 

Typical payload: Infrared interferometer spectrometer, temperature/humidity infrared radiometer, image-dissector camera system, filter wedge 

spectrometer, selective chopper radiometer, satellite infrared spectrometer, backscatter ultraviolet spectrometer, cloud-top altitude radiometer, 

monitor of ultraviolet solar energy, 

and interrogation, recording, and location system. 

Payload capacity: 135 kg (300 lb) 

weight; 100 W available power, 1 m3 

( 35 ft3 ) volume. 

Stabilization: Three-axis active control 

utilizing flywheels, rate gyros,1 horizon 

scanners, and reaction jets ; to +1 o all 

axes. Active control is augmented by 

gravity gradient torquing. 

N aminal orbit: Circular, high noon, sun 

synchronous, 80° retrograde, 1,110 km 

altitude, 107-min period. 

Design life: 1 yr. 

On board storage: High data-rate storage on two 5-channel tape recorders. 

Transmission: S-band communication, 

narrow bands ; PCM 4 kbps real time, 

128 kbps playback. 

Launch vehicle: Thorad/ Agena-D 

TIROS.-Ten spacecraft in the TIROS series 

of satellites (fig. 45), launched between 1960 

and 1965, were the precursors of the TOS 

(TIROS Operational Satellite) system. The 

spacecraft were utilized to test instrumentation 

and operational system concepts. TIROS design 

proved successful and formed the basis for the 

TOS configuration, which was used until replaced by the ITOS system. TIROS satellites 

returned 650,000 TV images during the program, which ended during 1973. 

21 

Description: 

Size: Pillbox shape, 18-sided polygon, 

56 em (22 in.) high, 107 em (42 in.) 

diameter. 

Weight: In orbit, 122-152 kg (270-338 

lb). 

Typical payload (not all instruments 

were carried on all flights) : Narrowangle TV, 5-channel scanning radiometer, 40° Hanel radiometer, University of Wisconsin bolometers, and au-
tomatic picture transmission (APT) 

system. 

Payload capacity: 6.9 dm3 (11.9 ft3 ) 

volume, 75 W total spacecraft power. 

Stabilization: TIROS 1-8 spin stabilization maintained by solid fueled spinup rockets. Mechanical nutation damper provided Vt o damping. TIROS 9-

10 had liquid dampers providing 

damping to < 0.1 o. Horizon infrared 

sensors provided input for attitude 

control maintained to ± 1 o in pitch, 

roll, and yaw. 

Orbit: TIROS 1-8 were programed for 

740-1,300 km altitude, circular ovbits 

with a 48°-60° inclination. TIROS 9-

10 were programed for sun-synchronous polar circular orbits. 

Design life: 3 mo. 

Onboard storage: Video tape recorders 

capable of storing 32 images/ orbit. 

Transmission : PCM telemetry system ; 

data rate for TV, 0.5 Mbps, for APT, 

2 kbps. 

Launch vehicle: Thor Delta. 

Earth Resources Technology Satellite 

(ERTS) .-The Earth Resources Technology 

Satellite (ERTS) is designed to demonstrate 

the feasibility of mapping and monitoring 

Earth surface features from space. It therefore 

carries multispectral imaging systems as well 

as auxiliary equipment to collect information 

needed to utilize data returned from these instruments. At least two spacecraft are planned 

in this series with the first one being launched 

into a near-polar circular orbit on July 23, 1972. 

During its first year of operation, performance 

of the ERTS spacecraft was literally flawless. 

Although the vidicons were used for only a 

relatively short period, the multispectral scanner was in continuous use, and the ERTS system in 1 year accomplished the following: (1) 

complete cloud-free coverage of the United 

States; (2) cloud-free coverage of a sizable 

percentage of the remaining land surface, polar, 

and coastal areas of the Earth ; and ( 3) repetitive coverage, based on the 18-day coverage 

cycle of ERTS, which shows significant temporal changes in the United States and other 

land areas of the world. 

Due to the spacecraft stability, scanner performance and system corrections made by 

NASA in processing the initial coverage, the 

imagery had the following characteristics: (1) 

multispectral ( 4-band) response with high 

radiometric fidelity, (2) high geometric fidelity 

in the form of a defined continuous map proj ection thus providing the potential for an automated mapping system, and (3) spatial frequency (resolution) based on picture elements 

of 80-m side -dimension at ground scale (figs. 

46, 47). 

22 

Description (ERTS-1) : 

Size: 3 m (10 ft) high x 4 m (13 ft) 

wide with solar panels extended; sensor ring, 1.5 m (5 ft) x 0.3 m (1ft). 

Weight: 815 kg (1,800 lb). 

Payload: Three return-beam vidicon 

cameras, 2 data-colleetion system receivers, 1 multispectral scanner ( 4 

bands), 2 video tape recorders. By late 

1973, the ERTS-1 return-beam vidicon cameras had had very limited use, 

and tape recording was only a fraction 

of original capability. 

Payload capacity: 240 kg (530 lb) 

weight, between 350 and 400 W available power, and 1m3 (35 ft3 ) volume. 

Stabilization: Three-axis active control 

utilizing flywheels, rate gyros, horizon 

scanners, and reaction jets ; to + 0.4 o 

in pitch and roll and ±0.6° in yaw. 

Nominal orbit: Near circular, sun synchronous with local sun time of 0942 

at descending mode, 99° inclination, 

900 to 950 km altitude. This orbit gives 

full Earth coverage except for polar 

regions every 18 days. 

Design life: 1 yr, but ERTS-1 may be 

operational for more than 2 yrs. 

On board storage: Two wide-band video 

tape recorders each having 30-min 

capacity at 15 Mbps PCM or 3.5 MHz 

video recording rate. Command storage for 30 commands. 

Transmission: S-band communication, 

wide band (video) 20 MHz bandwidth; 

narrow band PBM 1 kbps real time or 

24 kbps playback. 

Other: Capability exists for orbit adjustment with onboard propulsion, 
attitude determination system accuracies 0.07° in pitch and roll and 0.5° 

yaw. 

Launch vehicle: Long-tank Delta. 

ELECTRONIC DATA TRANSMISSION, GEOSYNCHRONOUS 

This mode has been well demonstrated by 

NASA's Advanced Technology Satellite (ATS) 

with remote sensors used for meteorological research. The next scheduled effort in this mode 

is the Synchronous Meteorological Satellite 

(SMS) which will combine technology research 

by NASA with meteorological operations and 

research by NOAA and is scheduled for launch 

in 197 4. These two types of satellites, though 

utilized for meteorological purposes, can also 

resolve the Earth's surface to a limited extent. 

For terrain observations a much higher resolution camera, coupled to a tracking telescope, is 

probably required. Such a system has been proposed to NASA by the U.S. Department of the 

Interior (1969), and NASA is supporting 

studies of this and related concepts. As indicated on page 31, a very large telescope 

launched by the Space Shuttle could be placed 

in geosynchronous orbit for Earth viewing. 

Application Technology Satellite ( ATS).-

The Application Technology Satellite (ATS) is 

a multipurpose platform used to test various 

types of space systems, including remote sensing, from geosynchronous altitude (figs. 48, 49, 

50). Through data obtained from this platform, 

concepts for such spacecraft as the SMS were 

formulated. 

Description: 

Size: Cylindrical, 142 em (56 in.) diameter, 135-182 em (53-72 in.) length. 

Weight: 295-355 kg (650-780 lb). 

Typical payload: Multicolor spin-scan 

camera, image dissector camera, communications experiments, and space 

environment experiments. Total spacecraft power, 190 W from solar panels, 

6 Ah batteries. 

Stabilization: Spin stabilized with 4 

monopropellant thrusters, each with 

2.2 kg ( 5 lb) thrust ; also magnetic 

torquing and gravity gradient stabilization. 

Nominal orbit: Geosynchronous altitude 

36,000 km (19,400 inm). 

Design life: 1 yr. 

On board storage: None. 

Transmission : PCM. 

Launch vehicle: Atlas Agena or Atlas 

Centaur. 

Synchronous Meteorological Satellite (SMS). 

-The Synchronous Meteorological Satellite 

(SMS), scheduled to be launched in 1974, is the 

prototype spacecraft to be used by NOAA in 

implementing the Global Atmospheric Research 

Program, a key step in the international World 

Weather Watch. It is the first spacecraft designed for this purpose to fly in geosynchronous orbit and thus will also be known as the 

Geostationary Operational Environmental Satellite (GOES). Aside from taking cloud-cover 

imagery, it will monitor the space environment 

and provide a data relay to aid in speeding up 

meteorological data collection (fig. 51). 

Description: 

Size: Pillbox shape, 190 em (75 in.) diameter, 122 em ( 48 in.) length. 

Weight : 225 kg ( 500 lb) in orbit. 

Payload : Visible and infrared spin-scan 

camera system, Space Environment 

Monitoring System, and data-collection system. 

Payload capacity: 75 kg (165 lb) weight 

and 1.26 m3 (35 ft 3 ) volume; 160 W 

available power. 

Stabilization : Spin stabilized by Delta 

launch vehicle and cold gas system; 

contains nutation dampers. 

Orbit: Geosynchronous altitude 36,000 

km (19,400 inm). 

Design life: 3 yr. 

On board storage : None. 

Transmission : PCM 194-bps S-hand 

communications. 

Launch vehicle: Thrust-augmented 

Delta. 

Proposed High-Resolution Geosynchronous 

Systems.-In 1969, the Department of the Interior proposed that a high-resolution Earthviewing tracking telescope be flown in geosynchronous orbit as part of the ATS program. Although not feasible for A TS, the concept of 

monitoring the Earth's surface from geosynchronous altitude has been considered by NASA 

and others. Interior recommended that an 

23 
operational system be developed by 1980. During 1972 and 1973, NASA supported studies of 

the Synchronous Earth Observation Satellite 

(SEOS) that involve the detailed study of the 

Earth from geosynch~onous orbit (fig. 52). 

Description (Interior proposal) : 

Orbit: Circular, geosynchronous on 

plane of the ecliptic with first satellite 

at about longitude 95° W., altitude 

36,000 km (19,400 inm). 

Design life: 5 to 10 yr. 

Sensor: Tracking telescope capable of 

resolving 20-50 m elements on the 

Earth's surface in at least three spectral bands. Instantaneous field of view 

to cover 40-80 km (on a side) of the 

Earth's surface. Primary optic would 

be of about 1 m diameter. 

Transmission: Capable of transmitting 

one 3-band scene per minute. 

Operation: Sensor directable to any section of a sizable part of the Earth's 

surface at any time, subject only to 

conditions of visibility. Six satellites 

could monitor all but the polar regions 

of the Earth on a continuing basis and 

in stereo mode, which provides high 

spatial precision. 

EXPERIMENTAL, U~MANNED, EXTRA TERRESTRIAL 

Prior to the space age, remote sensing of the 

Moon and planets had been limited to Earthbased optical and radio telescopes. Telescopes. 

have been carried in aircraft and balloons, but 

space systems that can escape the Earth's 

atmosphere and gravitational field have completely revolutionized the concepts of extraterrestrial exploration. Remote sensing of the 

Moon and planets is now feasible in any one of 

a variety of modes, which may be categorized 

as follows: 

1. Lander.-Either crash (probes) or soft 

landing. The latter may or may not be 

capable of returning to Earth. Remote 

sensing may be achieved during the approach, while on the body, or possibly 

during the return flight (if there is one). 

The U.S.S.R. has placed two landers on 

the Moon which collected samples and TV 

photos and then returned to EarthLUNA 16 in 1970 and LUNA 20 in 1972. 

2. Orbiter.-Orbits the body indefinitely. An 

orbiter of defined life which returns to 

Earth with hard-copy film is feasible and 

has been accomplished by the U.S.S.R. 

with the ZOND satellite during 1969 and 

1970. 

3. Flyby.-The spacecraft passes close to but 

does not go into orbit about the body of 

interest. This mode is applicable to the 

more distant planets. 

The first NASA extraterrestrial remote-sensing program involved the exploration of the 

Moon in support of the manned Apollo program. 

Ranger, Lunar Orbiter, and Surveyor were the 

three groups of missions which provided 

imagery and other data of the Moon essential 

to the lunar landings of Apollo. In addition to 

the lunar program, NASA has an extensive 

program of planetary exploration based on the 

Mariner spacecraft. Mars has been sensed by 

flyby missions, and the first Mars orbital mission occurred during 1971. In October 1973, 

Mariner 10 was launched on a flyby mission of 

Venus and Mercury. In 1972 and 1973, Pioneer 

missions to Jupiter were launched as precursors 

of further outer planet missions. Although plans 

for the Grand Tour flyby of up to five planets 

has been dropped by NASA, at least one Pioneer 

mission past Venus is scheduled for 1978, including instrumented probes as well as spacecraft sensing from orbit. Russian extraterrestrial remote-sensing programs are generally 

parallel to those of the United States. 

Unmanned extraterrestrial missions depend 

on electronic transmission of remote-sensored 

signals back to Earth. Transmission from the 

distant planets can be achieved although the 

amount of data is limited by the power, time, 

and equipment available. As with Earth-sensing 

missions, ground stations use line-of-sight radio 

signals to control the spacecraft, monitor its 

performance, and receive the sensor signals. 

On the more distant missions, transmission of 

signals back to Earth becomes a limiting factor. 

Power generally comes from solar panels, and 

since their generating capacity is limited, the 

rate of signal transmission is also limited. 

As spacecraft are defined for distant planetary missions, the problems of communication, 

orbit and attitude adjustment, and thermal control become increasingly difficult. Power is the 

24 
key to the problems, and solar panels have their 

limitations. Mariner flybys of Mars and Venus 

took days to transmit the contents of an image 

which took only a few milliseconds to acquire. 

The use of some form of nuclear power source 

appears to be the most promising answer to the 

basic problem for distant planetary explorations 

(Corliss, 1966). Radioisotope thermoelectric 

generators will be used to power the Pioneer 

and probably later outer planetary missions. Attitude reference on such missions depends 

heavily on the stars, but reference to the horizon of the body itself can also be applied to an 

orbiter. Durability and dependability become 

increasingly critical. 

The following programs are described: 

Ranger, Lunar Orbiter, Surveyor, Mariner flyby, Mariner Mars Orbiter, Mariner Venus/Mercury, Viking, and Pioneer mission to Jupiter. 

RANGER 

The Ranger lunar probes were first attempts 

by the United States to obtain closeup imagery 

of an extraterrestrial body. The series consisted 

of nine spacecraft; the first two, which failed 

at launching were designed to be tested in 

Earth orbit. Of the remaining seven, only 

Rangers 7, 8, and 9 successfully completed their 

missions of taking TV imagery before crashing 

on the Moon. The program ended when Ranger 

9 crashed on March 24, 1965 (fig. 53). 

Description: 

Shape: A truncated cone mounted on a 

hexagonal base 152 em (60 in.) in 

diameter. 

Typical payload: Six slow-scan vidicons 

with narrow- and wide-angle lenses of 

76 mm and 25 mm focal length. 

Payload capacity: 164 kg (362 lb) ; 

power from batteries, 40 Ah. 

Stabilization: Three-axis stabilization 

with gyros for inertial reference, 

Earth and Sun sensors for celestial 

reference, and cold gas active control. 

Orbit: Orbital planes as defined by the 

trajectories were inclined 15° to the 

lunar equator. 

Design life: 30 days. 

Onboard storage: None. 

Transmission: Two 960 MHz transmitters, 60 W power each ; two 960 MHz 

transponders, 3 W power each. 

Other : Midcourse correction thruster of 

28 kg (62 lb). Imagery taken during 

final 10-20 min of flight. 

Launch vehicle: Atlas Agena. 

LUNAR ORBITER 

The five Lunar Orbiter spacecraft were 

launched during 1966 and 1967 to photograph 

the Moon for selection of potential Apollo landing sites. The Orbiter series obtained data on 

lunar size, shape, and gravitational properties. 

The spacecraft carried instruments for sampling the near-lunar micrometeoroid and radiation environments (figs. 54 and 55). 

25 

Description: 

Size (exclusive of solar panels and antennas): 152 em (60 in.) diameter, 

168 em (66 in.) high. 

Weight: 388 kg (855lb). 

Typical payload : Two film cameras, film 

processors, scanner, and transmitters; 

pressure-type micrometeoroid detectors and two cesium iodide dosimeters. 

Payload capacity: 72.5 kg (160 lb) ; 

power, 110 W. 

Stabilization: Primary, three axis referenced to Sun and Canopus; backup, 

three axis inertial. Control accuracy 

-pitch, roll, and yaw to ±0.1 o with 

cold gas system. 

Nominal orbit: For Orbiters I, II, and 

III, selenocentric-perilune 50 km, apolune, 1,850 km, inclination 12°, period 

3.5 hr. Orbiters IV and V had different, and varying orbits. 

Design life: About 2 mo. 

Onboard storage: Command of 128 21-

bit words ; Bimat film. 

Transmission: PCM 50 bps, S-hand communication. 

Other: Onboard film processing, Bimat 

process. Optical-mechanical-electronic 

video scanner of developed film generates signal for transmission to 

Earth. 

Launch vehicle: Atlas Agena. 
SURVEYOR 

The Surveyor program was designed to demonstrate the ability to soft land on the moon 

as well as to transmit scientific and engineering 

information about the lunar surface (fig. 56). 

Of 7 spacecraft, 5 were successful and 2 had 

inflight failures prior to landing. 

Description: 

Size: Pyramidal open-frame structure 3 

m (10ft) high. With landing gear extended, can fit in a 4.25 m (14 ft) 

diameter space. 

Weight: 995-1,080 kg (2,200-2,380 lb). 

Typical payload: Survey TV camera and 

auxiliary mirrors, alpha-scattering instruments, and soil magnets. 

Payload capacity: Weight 40 kg (89 lb); 

power from 90 W solar panels and 

230-Ah rated batteries. 

Stabilization: Three-axis gyro referenced 

to Sun and Canopus with active control 

by cold gas jets. During landing an 

automated closed-loop system was used 

with radar altimeter and Doppler velocity sensors providing reference 

data. 

Orbit: Not applicable as Surveyor soft 

landed at several Apollo landing sites. 

Design life: 90 days including flight and 

lunar surface operation. 

On board storage: None. 

Transmission: Two transmitters, 2 receivers, 2 omnidirectional antennas, 

and 1 high-gain planar-array antenna 

for transmitting 600-TV-line data. 

Tracking and engineering data were 

transmitted on a 2,295 MHz band at 

lOW power. 

Launch vehicle: Atlas Centaur. 

MARINER (FLYBY) 

The Mariner spacecraft were designed to 

provide imagery and environmental information 

of the planets Venus and Mars. Because of the 

dense Venusian cloud cover, imaging systems 

were not included on missions to this planet. 

The spacecraft were designed to fly by the 

planets and then proceed into solar orbit (fig. 

57). In addition to the planetary measurements, 

the spacecraft provided useful data on the interplanetary environment. Of the seven spacecraft in this series, two failed at launch. Flights 

occurred between 1962 and 1969. 

Description: 

Size : Octagonal 127 em (50 in.) across 

flats, 66 em (26 in.) thick. In flight, 

3m (10ft) high, 7 m (23ft) diameter. 

Weight: 260 kg (575 lb). 

Payload: Mariner 4 to Mars-TV attached to Cassegrainian telescope, 

helium magnetometer, cosmic-ray detectors, and cosmic-dust detectors. 

Mariner 7 to Mars-two vidicon cameras, infrared spectrometer, infrared 

radiometer, ultraviolet spectrometer, 

conical radiometer. Mariner 5 to Venus 

-Faraday-cup detector, energetic-particles detectors, helium triaxial magnetometer. and ultraviolet photometers. 

Payload capacity: 48.5 kg (107 lb); 50 

W power. 

Stabilization: Three axis referenced to 

Sun and Canopus, cold gas system, 

pitch and yaw controlled to -+-1/2 o, 

roll -+-1~ o. 

Orbit: Heliocentric epoch 07/16/65 

period 567 days, apogee 1.58 astronomical units radius, perigee 1.1 astronomical units radius, and inclination 0°. 

Design life: 1 yr. 

On board storage: Tape recorded 7.83 x 

108 bits storage. 

Transmission : PCM 33.3 bps near Earth, 

8.33 bps near Mars. 

Other: Capability for in-flight trajectory 

adjustment. 

Launch vehicle: Atlas Agena. 

MARINER 71 (MARS ORBITER) 

The Mariner 71 (Mars Orbiter) project is a 

direct continuation of Ma:t;iner 69 missions. The 

two spacecraft for this mission were modifications of the Mars flyby configuration, with the 

main change being a larger propulsion system 

needed to place the spacecraft in orbit. The 

two missions were designed to map 70 percent 

of the Martian surface and make environmental 

26 
measurements but also were to look for seasonal changes and their relationship to surface 

phenomena. The two spacecraft were Mariner 

8 and 9. Mariner 8 failed at launch, but Mariner 9 flew successfully in 1971 (fig. 58). 

Description: 

Size: Octagonal 127 em (50 in.) across 

flats, 230 em (90 in.) high. In flight, 

690 em (272 in.) span including solar 

panels.· 

Weight: 544 kg (1,200 lb) not including 

propellants. 

Payload: Two TV cameras, ultraviolet 

spectrometer, infrared interferometer 

spectrometer, and infrared radiometer. 

Payload capacity: Weight 20 kg (44 lb); 

power 450 W, degrading to 330 W. 

Stabilization: Three-axis stabilized using 

inertial as well as Sun and Canopus 

sensors. Cold gas system pointing accuracy is in the order of ± 1 o. 

Nominal (mapping) orbit: 

Apoapsis 16,900 km 

Periapsis 1,610 km 

Period 12 h 

Inclination 50°-80° 

Design life: At least 90 days in Mars 

orbit. 

Onboard storage: 168 m (550 ft) magnetic tape, 1.8 x 108 bits capacity. 

Transmission: All-digital system with 

variable rate, engineering data at 33Ys 

or SYs bps and science data at realtime 50 bps. Block-coded real time, 16 

or 8 kbps. Block-coded stored 16, 8, 

4, 2, or 1 kbps. 

Other: Onboard computer flight programable with 512-word memory. 

Ground commandable two degrees of 

freedom. Scan platform for holding 

and pointing instruments. 

Launch vehicle: Atlas SLV-3C first 

stage. Centaur second stage. 

MARINER VENUS/MERCURY 

A modified version of the original Mariner 

spacecraft designed to fly by both Venus and 

Mercury, Mariner 10 was launched in October 

1973 and is scheduled to fly by Venus during 

February 1974, Mercury during March 1974. 

It may fly by Mercury again in September 197 4. 

Imagery of Venus will be limited to the cloud 

blanket and ultraviolet clouds that appear to 

circle the planet every 5 days. The imagery of 

Mercury should be equivalent to that of the 

best Earth-based imagery of the Moon. 

The spacecraft weighs 500 kg (1,100 lb) ; 

otherwise the description and payload are generally those of Mariner 9. The difference in 

weight is due to the elimination of two solar 

panels. 

VIKING 

Viking, the latest in NASA's series of unmanned planetary explorers, is scheduled for a 

1975 mission to Mars. The program calls for 

insertion of two spacecraft into Mars orbit, 

each spacecraft sending a separate landing 

craft to the surface. Viking's primary purpose 

is to determine if life once existed, is present, 

or might develop on Mars (NASA, Langley 

Research Center, 1970). 

The Viking spacecraft will travel some 460 

million miles through space on its journey of 

about 1 year (fig. 59). Once in Mars orbit, the 

spacecraft will separate into an orbiter and a 

lander. While the orbiter performs remotesensing and water-vapor mapping, the lander 

will take panoramic color pictures of the surroundings and obtain geophysical and meteorological data. 

27 

Description : 

Size: Total length of Titan III/Centaur 

spacecraft 48.8 m (160 ft). Lander 

capsule, 4.3 m (14 ft) diameter x 4.9 

m (16 ft) height (in flight). Orbiter 

spread 10.7 m (35 ft) including solar 

panels. 

Weight: Total launch weight of orbiter/ 

lander 3,175 kg (7,000 lb) of which 

the orbital insertion engine and fuel 

will be 1,815 kg ( 4,000 lb). 

Payload: Two TV cameras for imaging, 

infrared spectrometer for water-vapor 

mapping, infrared radiometer for 

thermal mapping, and a radio subsystem. 

Payload capacity of Orbiter: 68 kg (150 

lb) for scientific experiments to record 

and relay data. 
Stabilization: Three-axis, using inertial 

as well as Sun and Canopus sensors. 

Cold gas system pointing accuracy is 

in the order of +1 °. 

Nominal orbit: 

Apoapsis 

Periapsis 

Period 

32,550 km 

14,964 km 

24.6 h 

Inclination (has not been selected) 

Design life of Orbiter: 140 days after 

Mars orbit insertion, consisting of 50 

days before lander separation and 90 

days after landing. Either orbiter can 

support either lander for the lander's 

lifetime, which is 90 days after 

landing. 

On board storage: Similar to but somewhat larger than Mariner 9. 

Launch vehicle: Titan III/Centaur. 

PIONEER (JUPITER) 

The purpose of the Pioneer F and G missions 

is to extend interplanetary measurements farther out into the solar system. Specifically, the 

mission is to provide information on the asteroid belt that lies between Mars and Jupiter 

and to fly by and gather data on Jupiter itself 

(fig. 60). Pioneer F (now Pioneer 10) was 

launched March 2, 1972; Pioneer G (now Pioneer 11), April 5, 1973. Interplanetary travel 

time is expected to be 600 and 700 days. 

During 1973, a Pioneer Venus flight for 1978 

was under study by NASA but was not yet defined or approved. 

Description (Pioneer/Jupiter) : 

Size: 2.4 m (8 ft) length, 5.5 m (18 ft) 

diameter. 

Weight: 254 kg (560 lb). 

Typical payload: Meteoroid detector, asteroid/meteoroid detector, plasma 

analyzer, helium vector magnetometer, 

charged-particle detectors, cosmic-ray 

telescope, Geiger-tube telescope, trapped- radiation telescope, ultraviolet 

photometer, infrared radiometer, and 

imaging photopolarimeter. 

Payload capacity: Weight 28 kg ( 62 lb) ; 

power 23 W supplied by radioisotope 

thermonuclear generator. 

Stabilization: Spin-stabilized at 4-5 r I 

min, with fine adjustment by hydrazine-fueled thrusters. Attitude reference by Sun and star sensors. 

Orbit: Trajectory to carry spacecraft 

within 160,000 km of Jupiter and then 

out of solar system. 

Design life: About 2 yr. 

On board storage: Tape recorder. 

Transmission: S-hand communications, 

maximum data rate from vicinity of 

Jupiter, 1,024 bps. Data can be transmitted at eight different rates and 

formats. S-hand command system capable of 255 discrete commands. 

Launch vehicle: Atlas Centaur. 

EXPERIMENTAL, MANNED SPACE FLIGHT 

To date, no manned space flights have been 

defined with remote sensing as the prime objective. The Manned Orbiting Laboratory, an Air 

Force project that was canceled, was probably 

the closest U.S. approach to the remote-sensing 

concept. However, the Manned Orbiting Laboratory had numerous other objectives in addition to remote sensing. NASA's Mercury, 

Gemini, and most Apollo flights were concerned 

with getting man to the Moon, and remote sensing, as typified by hand-held snapshots, was incidental. Apollo 9 carried a well-defined multispectral Earth-viewing experiment, S0-65; 

starting with Apollo 13, a variety of fixed and 

mobile cameras were carried in an effort to obtain systematic photo coverage of selected portions of the Moon. 

The Apollo program also involved photography and other sensing of the lunar surface. 

Hand-held and mounted cameras (film and TV) 

were used on all missions that landed on the 

Moon, and starting with Apollo 15, the Lunar 

Rover Vehicle provided a moving platform for 

sensors on the Moon's surface. 

Skylab, launched in May 1973, carries a battery of Earth-sensing experiments although 

astronomic observations of the Sun and the 

various experiments aimed at defining man's 

abilities and limitations in the space environment have a higher priority. The Space Shuttle 

has been defined, but other post-Skylab manned 

space programs cannot be evaluated as remotesensor platforms now. 

28 
Russian manned space flights to date have 

been limited to Earth orbits, but otherwise they 

are parallel to the United States efforts, except 

that their flights emphasize the development of 

manned space stations, which do have a sizable 

remote-sensing potential. 

Vehicles of the following programs are described: Mercury, Gemini, Apollo, Skylab, and 

Space Shuttle. 

MERCURY 

Project Mercury was the first series of manned space flights conducted by the United 

States. The capsule was designed for one man 

and carried many experiments, including terrain photography. The experiment was extremely successful and led to further experimentation in later manned programs. There 

were four orbital missions in this series (fig. 

61). 

Description : 

Size: Cone, 189 em (74 in.) diameter, 

335 em ( 132 in.) long. 

Weight: 1,360 kg (3,000 lb). 

Typical camera payload: 70-mm modified Hasselblad camera, 35-mm zodical light camera, and 16-mm Maurer 

camera. 

Payload capacity: Size and weight not 

available. Total spacecraft power from 

500-Ah batteries. Window-viewing 

capabilities. 

Stabilization: Three-axis attitude control by jet reaction thrusters with automatic and manual modes. 

Orbit: Apogee 266 km (144 inm), perigee 161 km (87 inm), inclination 

:::::::::32° to Equator. 

Design life : 3 days. 

Onboard storage : Film. 

Transmission: Not applicable. 

Launch vehicle: Atlas. 

GEMINI 

Project Gemini was a continuation of Mercury. A new design spacecraft enabled two men 

to remain in orbit for an extended period and 

thus allowed for more sophisticated and selective experimentation. There were 10 missions in 

the Gen1ini program. 

Description : 

Size: Truncated cone, 305 em (10 ft) 

diameter, 574 em (18.8 ft) long. 

Weight: 3,175 kg (7,000 lb). 

-Typical camera payload: 70-mm modified Hasselblad and 70-mm and 16-mm 

Maurer cameras. 

Payload capacity: 125 kg (275 lb), total 

spacecraft power from 160-Ah batteries and 6,570 Ah-fuel cells. Viewing 

through two windows or with hatches 

open. 

Stabilization : Three-axis jet-reaction 

attitude control system with automatic 

and manual modes. 

Orbit: Up to 1,370 km (740 inm) apogee, inclination :::::::::30° to Equator. 

Design life: 2 wks. 

On board storage: Film. 

Transmission: Not applicable. 

Launch vehicle: Titan II. 

APOLLO 

The Apollo program followed Gemini in extending manned space activities. In addition to 

providing a mechanism for lunar exploration, 

Apollo again demonstrated the useful application of Earth-orbital photography. Apollo 6 

flew in unmanned mode, but considerable photography of the Earth was obtained on that 

mission. The S0-65 multispectral photographic 

experiment (Apollo 9) provided the basis for 

definition of such dedicated remote-sensing missions as ERTS. 

On the early lunar missions, Apollo 8 through 

14, the only remote sensors were cameras, primarily the 70-mm Hasselblad with interchangeable lenses. On Apollo 15, 16, and 17, much 

larger camera systems and other orbital remote 

sensors were mounted in the service module. 

These three missions produced high-quality 

mapping photographs for about 25 percent of 

the Moon's surface, while other sensors which 

could also operate on the dark side increased 

the total coverage to about 35 percent. 

29 

Description: 

Size: Command module 4 m (13 ft) 

diameter, 3.5 m (11.5 ft) long. Service 

module 4 m (13 ft) diameter, 7.5 m 
(25 ft) long. Lunar excursion module 

6.7 m (22 ft) high, 9.5 m (31 ft) diagonal across lunar landing pads. 

Weight: Command module 5,760 kg 

( 12,700 lb), service module 23,500 kg 

(51, 700 lb), lunar excursion module 

15,300 kg (33,700 lb). 

Typical sensor payloads: 70-mm Hasselblad, 16-mm Millikon, 35-mm Maurer, 

460-mm (18-in.) Hycon, and color TV 

in command and lunar modules. Starting with Apollo 15, lunar-sensing devices were carried in a bay of the 

service module and designated the Scientific Instrument Module (SIM). On 

Apollo 15 and 16 these devices included: 76-mm (3-in.) mapping camera, 76-mm (3-in.) stellar-attitude 

camera, 610-mm (24-in.) optical-bar 

panoramic camera, laser altimeter, 

mass spectrometer, gamma-ray spectrometer, and X-ray and alpha particle spectrometer. On Apollo 17, the 

spectrometers were replaced by the 

lunar sounder (side-looking radar) 

and infrared scanning radiometer. The 

SIM in lunar orbit is shown in figure 

62. A diagram indicating the various 

sensors is shown in figure 63. The 

Lunar Rover Vehicle, also carried on 

Apollo 15, is described separately. 

Payload capacity: Size and weight not 

available; total spacecraft power from 

1,250-Ah batteries and 19,300-Ah fuel 

cells. 

Camera viewing: Through windows at 

various attitudes or as exposed in the 

SIM. 

Stabilization: Three-axis, jet-reaction 

attitude control with automatic rate 

and manual modes operating liquid 

propellant thrusters. 

Orbit: Earth, lunar, lunar trajectory. 

Earth orbits had an inclination of 

about 30° to Equator. 

Design life: About 2 wks. 

On board storage: Film. 

Transmission : TV in real time. 

Launch vehicle: Saturn 1 or 5. 

LUNAR ROVER VEHICLE 

The Lunar Rover Vehicle (LRV), which was 

used on the Moon by the Apollo 15, 16, and 17 

astronauts, has been called by NASA "a manned spacecraft on wheels." It is undoubtedly the 

most advanced and highly specialized motor 

vehicle ever built. Since it carried an array of 

remote sensors and had a unique application, it 

is included here even though it is a groundbased platform. The whole vehicle weighed 220 

kg ( 480 lb) on Earth and carried a payload of 

about 450 kg (1,000 lb) consisting of the two 

astronauts and their life-supporting equipment 

weighing 360 kg (800 lb). The remaining 90 

kg (200 lb) of payload included cameras, scientific experiments, and rock samples on the return to the service module (fig. 64). 

Performance: 

Speed: Maximum 15 km/h (9 mi/h). 

Cruising 8 km/h ( 5 mi/h) forward or 

backward. 

Climb: LRV can climb a 20° slope and 

stop on a 30° slope. It can climb obstructions up to 0.3 m ( 1 ft) high and 

cross crevasses 70 em (28 in.) wide. 

Weight: Empty 220 kg ( 480 lb) ; with 

payload 450 kg ( 1,000 lb). 

Size: Length 3.1 m (10.2 ft), width 1.8 

m (6 ft), wheelbase 2.3 m (90 in.), 

and clearance 36 em (14 in.). 

Range : 65 km ( 40 mi) total distance. 

Power: Two nonrechargeable 36-V silver-zinc batteries. 

Engines : Each wheel powered by a 185-

W ( 0.25-hp) electric motor. Power 

steering by two 75-W (0.1-hp) electric 

motors, one for each axle. 

Special equipment: The LRV carried a 

dead-reckoning navigation system 

which reported speed, total distance 

traveled, and direction and distance to 

the lunar excursion module throughout the entire traverse. 

A lunar communications relay unit transmitted directly to Earth the radio signals of the 

astronauts' voices, biomedical data, and color 

TV images from a TV camera mounted near the 

front of the vehicle. The vehicle carried a 16-

mm movie camera, and a 70-mm Hasselblad 

30 
camera with interchangeable lenses. A handheld unit for drilling cores of lunar geologic 

material as deep as 3 m (10 ft) was carried 

along with rakes and tongs for collecting samples. A magnetometer and traverse gravimeter 

were also included. 

SKYLAB 

Skylab-A, which was launched in May 1973, 

is aimed at increasing man's role as an experimenter in space. Skylab utilizes the empty tank 

of a Saturn IVB as a semipermanent space base, 

which was visited three times during the program for long-duration experimentation. The 

program ended early in 197 4. The data obtained 

during each visit were returned with the crew 

for analysis on the ground. The particular instrument cluster pertinent to this circular is the 

Earth Resources Experiment Package (EREP), 

a module located physically in the docking adapter. Extensive observations of the Sun were also 

carried out with special solar sensors (figs. 65 

and 66). 

Description (Apollo-derived spacecraft designed for intermittent manned occupancy for a wide variety of experiments, including remote sensing of the 

Earth): 

Size: Not applicable. 

Weight: Not applicable. 

Remote-sensor payload: Multispectral 

photographic· assembly consisting of 

six bore-sighted cameras of 152-mm 

(6-in.) focal length, 460-mm (18-in.) 

focal length Earth Terrain Camera 

(ETC), infrared spectrometer, 13-band 

multispectral scanner, microwave radiometer/scatterometer and altimeter, 

and L-band radiometer. 

Payload capacity (not including control 

units, film storage, etc.): 1.3 m3 (45 

ft 3 ) volume, 340 kg (745 lb) weight, 

and special viewing windows. 

Stabilization: Three-axis stabilization 

control mainly by jet reaction engines. 

Desired attitude determination to 

+0.1 o. Desired attitude rate to be 

known to +0.005° /s. 

Nominal orbit: 435 km (235 inm) altitude and 50° inclination to Equator. 

Design life: 28 to 56 or 85 days per visit, 

three visits, nearly 1 year overall. 

On board storage: Film in film vaults; 

magnetic tape, voice annotation and 

digital. 

Other: Special mounts provided for instruments. 

Launch vehicle: Saturn. 

SPACE SHUTTLE 

Early in 1972 the Space Shuttle was defined 

and development started (NASA, 1972). The 

shuttle is scheduled to be operational by 

1980 and involves the concept of a reusable 

manned space vehicle. The shuttle is scheduled 

to launch, service, and retrieve unmanned satellites but has also been defined for manned missions (sorties) which include remote sensing of 

the Earth (fig. 67). 

31 

Description (Winged orbiter, capable of reentry and reuse, attached to large propellant containers for launching) : 

Size : Wingspan 24 m ( 80 ft), length 38 

m (124ft), with a payload bay 4.5 m 

(15 ft) in diameter by 18 m (60 ft) 

in length. 

Weight: Payload weight is 29,500 kg 

(65,000 lb) for takeoff and 18,000 kg 

(40,000 lb) for landing. 

Remote-sensor payload: Not defined to 

date, but sortie configuration would 

permit the use of a very large assortment of remote sensors, including the 

Large Space Telescope (LST) with 

3-m (10-ft) diameter primary optics. 

The LST is designed for astronomic 

observations but might be adapted for 

Earth observations, particularly from 

a geosynchronous orbit. 

Stabilization: Not defined. 

Nominal orbit: 200 km (108 inm) altitude at various inclinations, including 

polar. With a secondary propulsive vehicle called the "Space Tug," geosynchronous orbits or trajectories to the 

Moon or planets are feasible. 

Design life: Life of an unmanned satellite which may be launched by the 

shuttle is indefinite. The manned sortie mode is nominally of 7 days dura-
tion but can be extended to 30 days 

when required. The orbiter, being reusable, has an extended life. 

OPERATIONAL-NOAA 

Remote sensing from space has reached the 

operational stage only in meteorology. The National Oceanographic and Atmospheric Administration (NOAA) is the United States agency 

charged with such operations. NOAA absorbed 

the Environmental Science Services Administration (ESSA) which controlled the original 

operational meteorological satellite. The first 

operational weather satellites were the ESSATOS series with the first launch in 1966. Since 

that date at least one weather satellite has been 

in operation continuously. In 1970, the ITOS 

series was introduced. The latest, ITOS-D, was 

launched in 1971. Both TOS and ITOS satellites 

fly in near-polar sun-synchronous orbits and 

image the globe every 12 hours. The SMS, which 

will be geostationary, has been described under 

NASA spacecraft, but it will also perform an 

operational role as the GOES satellite. ESSATOS, ITOS-A, -B, -C, and -D are described 

here. 

The evolution of the meteorological satellites, 

including the experimental NASA and the operational systems, is outlined in figure 68, in 

which the actual missions are tabulated. 

ESSA-TOS 

The ESSA-TOS spacecraft were the first of 

the operational meteorological satellite system. 

They were used to provide cloud imagery for 

operational as well as res~arch usage. Specifically designed to provide a platform for the 

instrumentation developed to meet mission requirements, these spacecraft can be considered 

as a group of separate but coordinated subsystems operating as part of an overall datagathering system. This type of spacecraft has 

been superseded by the ITOS system. Two versions of the ESSA spacecraft were operated. 

One version carried an Advanced Vidicon Camera System (AVCS), which stores the sensor 

signal on board and then transmits to a designated receiver in a short period. The other version carried an Automatic Picture Transmission (APT), which transmits in real time to 

any station within range (basically line-ofsight) of the satellite. APT receivers numbering in the hundreds are relatively simple to 

construct, and therefore the APT system is 

available on a worldwide basis (figs. 69 and 70). 

Description: 

Size: Pillbox 18-sided polygon, 56 em 

(22 in.) high, 107 em (42 in.) diameter. 

Weight: 148 kg (327lb) in orbit. 

Typical payload: A VCS version carried 

redundant 800-line vidicon cameras 

with tape recorders and low-resolution 

flatplate radiometer. APT version carried tape recorders replaced with APT 

transmission equipment. 

Payload capacity: 6.9 dm3 ( 420 in. 3 ) volume, 75 W total spacecraft power. 

Stabilization: Spin stabilized with magnetic torquing attitude control, liquid 

dampers provide short-term nutation. 

Attitude controlled to +-1 o in roll and 

yaw, attitude determination accuracy 

±0.1 o, short-term nutation controlled 

to +-0.2°. 

Nominal orbit: Circular, 1,460 km (790 

inm) altitude; inclination 101.6° (78.4 o 

to Equator); period 115.1 min; AVCS 

version sun synchronous at 1500 local 

solar time, APT version sun synchronous at 0900 local solar time. 

Design life: 6 mo. 

Onboard storage: Video tape recorders. 

Transmission: PCM TV 0.5 Mbps, APT 

2 kbps. 

Other: Cameras are mounted on the 

spacecraft as spokes on a wheel so that 

they point directly down once during 

each spin of the spacecraft as it rolls 

along its orbit. 

Launch vehicle: Thrust-augmented Delta. 

ITOS 

The ITOS (A, B, C), an improved TOS satellite, represented a newer development in the 

meteorological system. Its configuration included a larger payload with redundant APT 

and A VCS systems (fig. 71). 

Description: 

Size: 100 em x 100 em x 122 em (39 in. 

32 
x 39 in. x 48 in.), excluding solar arrays. 

Weight: 308 kg (680 lb). 

Payload : Two scanning radiometers, 2 

AVCS, 2 APT systems, 1 flatplate radiometer, and 1 solar proton monitor 

(SPM). 

Payload capacity: Weight 59 kg (130 

lb) ; available power 32 W. 

Stabilization: Three-axis stabilized utilizing momentum wheel with passive attitude control provided by magnetic 

torquing. Liquid dampers used to control short-term nutation. Stabilization 

is to +1 o. Short-term nutation is to 

+0.3° with short-term rate less than 

0.05° /s. Attitude determination accuracy +0.1 o. 

Nominal orbit: Circular, 1,460 km (790 

inm) altitude, sun synchronous at 1500 

local solar time, inclination 101.6° 

(78.4 o to Equator), period 115.1 min. 

Design life: 6 mo. 

Onboard storage: 44-min incremented 

video tape recorder. 

Transmission: Redundant FM transmitter for APT, redundant PM transmitter for SPM, redundant S-hand transmitter for wide-band data. 

Launch vehicle: Delta. 

ITos-n 

The ITOS-D satellite was specifically designed to provide a platform for instrumentation developed to meet NOAA's mission requirements. The configuration enabled stabilization permitting the sensors continually to face 

the Earth. It has the capability to view the globe 

twice each day, once during daylight, once at 

night (fig. 72). 

Description: 

Size: 100 em x 100 em x 108 em (39 in. 

x 39 in. x 42 in.) . 

Weight: 355 kg (785 lb). 

Payload: Two-channel scanning radiometer, 2-channel very-high-resolution 

radiometer, vertical temperature profile radiometer, and SPM. 

Payload capacity: Weight 57 kg (125 

lb), available power 89 W. 

Stabilization: Three-axis stabilization 

utilizing momentum wheel. Attitude 

controlled to + 1 o with reference to 

Earth's magnetic field. Attitude determination accuracy 0.! o. Short-term 

nutation controlled to +0.3° by liquid 

dampers. Attitude rate less than 0.05 

dampers. Attitude rate less than 

0.05° /s. 

Nominal orbit: Circular, 1,460 km (790 

inm) altitude, sun synchronous at 

0900 local solar time, inclination 

101.6° (78.4 o to Equator), period 

115.1 min. 

Design life: 6 mo to 1 yr. 

On board storage: 44-min incremental 

video tape recorder. 

Transmission: Redundant PM transmitter for SPM data, redundant S-hand 

transmitters for wide-band data. 

Launch vehicle: Delta. 

GOES 

(See Synchronous Meteorological Satellite, 

page 23.) 

BIBLIOGRAPHY 

Aerospac-e Industries Assoc., 1970, The 1970 aerospace 

yearbook, 48th ed.: Washington, D.C., p. R-99. 

Allied Research Assoc., Inc., 1965, Nimbus I users' 

catalog: AVCS and APT: Prepared for Nat'l 

Aeronautics and Space Adm. under contract NAS5-

3253. 

American Society of Photogrammetry, 1960, Manual of 

photographic interpretation. 

--1966, Manual of photogrammetry, 3d ed. 

--1968, Manual of color aerial photography. 

Aviation Week and Space Technology, Nov. 29, 1971, 

Nov. 13, 1972, and Aug. 13, 1973. 

Barton, J. H., 1972, U.S. Navy cartography: Am. Soc. 

of Photogramm .. Photogramm. Eng., v. 38, no. 2, 

p. 147-154. 

Boeing Co., 1967a, Lunar Orbiter 1, extended mission 

spacecraft subsystem performance. Nat'l. Aeronautics and Space Adm., CR-870. 

--1967b, Lunar Orbiter 2, mission system performance. Nat'l. Aeronautics and Space Adm., CR66437. 

Briggs, D. E., Scanlon, .:f. G., Golden, R. R., and Kaeding, D. A., 1969, TOS Evaluation Genter (TEC) 

post-operational test results for ESSA 3: Nat'l. 

Aeronautics and Space Adm., Goddard Space 

Flight Center, X-481-69-457. 

33 
California Institute of Technology, Jet Propulsion 

Laboratory, 1965, From project inception through 

midcourse maneuver, v. 1 of Mariner Mars 19'64 

project report, mission and sp·acecraft development: Calif. Inst. of Tech., Jet Propulsion Lab. 

Tech. Rept. 32-740. 

--- 1966a, Mission description and performance, pt. 

1 of Ranger 8 and 9: Calif. Inst. of Tech., Jet 

Propulsion Lab. Tech. Rept. 32-800. 

--- 1966b, PDP Mariner Mars 1969: Calif. Inst. of 

Tech., Jet Propulsion Lab. Proj. Doc. 69. 

--- 1967, Mariner Mars '69 project: Calif. Inst. of 

Tech., Jet Propulsion Lab. Rept. 13. 

--- 1969a, Mission plan, pt. 2 of Mariner Mars 1969 

mission plan and requirements: Calif. Inst. of 

Tech., Jet Propulsion Lab. PD91. 

--- 1969b, PDP Mariner Mars 1969 project: Calif. 

Inst. of Tech., Jet Propulsion Lab. Proj. Management Rept. 41. 

--- 1969c, Surveyor project final report: Calif. Inst. 

of Tech., Jet Propulsion Lab. Tech. Rept. 32-1265. 

--- 1971, The deep space network: Calif. Inst. of 

Tech., Jet Propulsion Lab. Tech. Rept. 32-1526, v. 

1. 

Corliss, W. R., 1966, SNAP nuclear space reactors: 

U.S. Atomic Energy Comm. 

Doyle, G., Jr. and Vorachek, J., 1971, Investigation of 

stability characteristics of tethered balloon systems: U.S. Air Force Cambridge Research Labs., 

AFCRL-71-0406. Prepared by Goodyear Aerosp,ace 

Corp. 

Doyle, G., Jr., Vorachek, J., and Block, D., 1973, Stability and dynamic behavior of two tethered balloon 

systems: U.S. Air Force Cambridge Research 

Labs., AFCRL-TR-73-0396. Prepared by Goodyear Aerospace Corp. 

Driscoll, Everly, 1971, The bureaucratic odyssey of a 

space mapping camera: Sci. News, v. 100, no. 22, 

p. 362. 

Electro-Optical Systems Design, 1970, Up-up-and-away 

in balloon launch, Stratoscope photographs, planets, 

galaxies (Project Stratoscope) : Electro-Optical 

Systems Design 5/70. 

Fordyce, D. C., 1969, PDP Applications Technology 

Satellites ATS-A through E. Nat'l. Aeronautics 

and Space Adm., Goddard Space Flight Center 

Proj. Dev·el. Plan (PDP). 

General Electric Co., 1967a, Percheron suitability, application "A", payloads: Gen. Elec. Co. Doc. No. 

67SD4287. Prepared for Nat'l. Aeronautics and 

Space Adm., Off. Space Sci. and Applications. 

--- 1967b, Summary report covering an analysis of 

spacecraft systems with physical recovery capability to perform earth oriented applications experiments: Prepared for Nat'l. Aeronautics and Space 

Adm. under contract NAS-W-1691, 3v. 

-.-1971, ERTS data users handbook: Gen. Elec. Co. 

Doc. No. 71SD4249. Prepared for Nat'l. Aeronautics and Space Adm., Goddard Space Flight Center 

under contract NAS 5-11320. 

Gerwin, H. L., ed., 19:67, ATS-4 GSFC concept design 

study: Nat'l. Aeronautics and Space Adm., Goddard Space Flight Center, X-730-67-10. 

Goodyear Aerospace Corp., Aero-Mechanical Programs, 

1971, Airborne sensor pl'atform: Goodyear Inf. 

Circ. 8330-9/71. 

Heacock, R. L., Kuiper, G. P., and Shoemaker, E. M., 

1966, Experimenters analysis and interpretations, 

pt. 2 of Ranger 8 and 9: Calif. Inst. of Tech., Jet 

Propulsion Lab. Tech. Rept. 32-800. 

Hudson, J . .F., 1968, Research role for the Learjet: 

Wichita, Kans., Learjet Contrails. 

--- 1971, Aircraft performance, Gates Learjet 24: 

Wichita, Kans., gates Learjet Corp. 

Klass, P. J ., 1971, Secret sentries in space: New York, 

Random House. 

Kollsman Instrument Corp., n.d., U.S. Air Force AN/ 

USQ-28 aerial electro-photo mapping system: Elmhurst, N.Y., Standard Kollsman Industries. 

Kosofsky. L. J., 1964, Mission description and performance, pt. 1 of Ranger 7: Calif. Inst. of Tech., Jet 

Propulsion Lab. Tech. Rept. 32-700. 

Lockheed Missiles and Space Co., Space Systems Division, 1967, NASA-AGENA: Sunnyvale, Calif., 

Lockheed Missiles and Space Co., NAP-E1 2-4-67. 

Lockheed Missiles and Sp·ace Co., 1969, Earth Resources Technology Satellite film recovery system, 

a complementary approach to the recovery of 

earth resources data: Lockheed Missiles and Space 

Co. with Mark Systems, Inc. 

Mattill, J. I., ed., 1971, The lunar rover: Mass. Inst. 

of Tech. Technology Rev., v. 73, no. 9. 

Morris, A L., and Stefan, K. H., 1969, High altitude 

balloons as scientific platforms: Boulder, Colo. 

Nat'l. Center for Atmospheric Research. 

Myers, P. F., 1968, Tethered balloon handbook: U.S. 

Air Force Cambridge Res·earch Labs., AFCRL-69-

0017. Prepared by Goodyear Aerospace Gorp. 

Myers, P., and Vorachek, J., 1971, Definition of tethered 

balloon systems: U.S. Air Force Cambridge Research Labs., AFCRL-71-0213. Prepared by Goodyear Aerospace Corp. 

National Aerospace Education Council, 1970, 1970 

United States aircraft, missiles and spacecraft: 

Wash., D.C. 

Oelila, R. G., Brown, I. H., Jr., and Minckler, R. D., 

1971, A survey and technical assessment of lowaltitude tethered balloon systems: Columbus, Ohio, 

Battelle Columbus Labs., Tactical Tech Center. 

Quick, J. R., 1964, Eye in the sky: Dayton, Ohio. 

Radio Corporation of America, 1969, Instructions and 

operating handbook for the Improved TIROS Operational System (ITOS) and the TIROS Operational System (TOS), pt. 4. 

Remote Sensing, Inc., 1971, -Brochure of remote sensing. 

Schnapf, A., 1963-64, TIROS, the television and infrared observation satellite: British Interplanetary 

Soc. Journal, v. 19, p. 386-409. 

Schultz, F. L., 1966, Mariner-Mars science subsystem: 

N at'l. Aeronautics and Space Adm., TN 32-813. 

34 
Science, 1962, Mission of Mariner 2, preliminary observations: Science, v. 138. p. 1095-1099. 

Science News, 1971, Scientific spy eyes for NASA: Sci. 

News, v. 99, no. 15, p. 240. 

Sloan, R. K., 1968, Mariner Mars 1964 project report, 

scientific experiments: Calif. Inst. of Tech., Jet 

Propulsion Lab. Tech. Rept. 32-883. 

Sp·ace Business Daily, 1971, v. 56, no. 2·1. 

Stampfl, R. A., 19·63, Nimbus spacecraft and its communication system as of Sept. 1961: Nat'l. Aeronautics and Space Adm., TN D-1422. 

Stehling, K. R., 1971, A case for more balloon astronomy: Smithsonian, v. 2, no. 3, p. 28-33. 

Stoldt, N. W., and Havanac, P. J., 1973, Compendium 

of meteorological satellites and instrumentation: 

Nat'l. Aeronautics and Space Adm. Nat'l. Space 

Science Data Center, NSSDC 73-02. Prepared by 

U.S. Air Force Environmental Tech. Applications 

Center. 

Taylor, J. W. R., ed., v. d., Jane's all the world's aircraft: London, Jane's Yearbook, 19·61-62, 1962-63, 

1963-64, 1966-67, 1967-68, 1969-70, 1970-71, 1971-

72, and 1972-73. Also distributed through McGrawHill Book Co., N.Y. and McGraw-Hill Co. of 

Canada, Scarborough, Ontario. 

TRW, 1969, TRW space-log: Redondo Beach, Calif. 

U.S. Air Force, 1970, Standard aircraft characteristics. 

U.S. Air Force Cambridge Research Laboratories, 1963, 

AFCRL balloon symposium proceedings: U.S. Air 

Force Cambridge Research Labs., AFCRL-63-919. 

--- 1965, AFGRL scientific balloon symposium, 1964, 

proceedings: U.S. Air Force Cambridge Research 

Labs., AFCRL-65-486. 

--- 1966, AFCRL scientific balloon workshop, 1965, 

proceedings: U.S. Air Force Cambridge Research 

Labs., AFCRL-66-309. 

--- 1967, Fourth AFCRL scientific balloon symposium proceedings: U.S. Air Force Cambridge 

Research Labs., AFGRL-67-0075. 

--- 1968a, AFCRL tethered balloon workshop, 1967, 

proceedings: U.S. Air Force Cambridge Research 

Labs., AFCRL-68-0097. 

--- 1968b, Fifth AFGRL scientific balloon symposium proceedings: U.S. Air Force Cambridge Research Labs., AFCRL-68-0661. 

--- 1970, Sixth AFCRL scientific balloon symposium proceedings: U.S. Air Force Oambridge Research Labs., AFCRL-70-0543. 

U.S. Dept. of the Interior, 1969, Proposal to NASA 

for a high-resolution earth sensing experiment 

from geostationary (geosynchronous) orbit. 

--- 1970, Proposal to NASA for a film-return earth 

sensing experiment. 

U.S. Fed·eral Aviation Agency. n.d., Moored balloons, 

kites, unmanned rockets and unmanned free balloons, pt. 101, v. 6 of Federal Aviation Regulations. 

U.S. National Aeronautics and Space Administration, 

1965, Mariner-Venus 1962, final project report: 

Nat'l. Aeronautics and Space Adm. SP-59. 

--- 1966, Manned space flight experiments, interim 

report Gemini 9 mission. 

--- 1971, The Pioneer mission to Jupiter: Nat'l. 

Aeronautics and Space Adm., SP-268. 

--- 1972, Space Shuttle: Washington, D.C., 23p. 

U.S. National Aeronautics and Space Administration, 

Goddard Space Flight Center, 1967a, ATS-D ( S/ 

G 1) spacecraft and telemetry measurements list: 

Nat'l. Aeronautics and Space Adm., Goddard Space 

Flight Center, S-460-ATS-15. 

--- 1967b, Operations plan 1967 Applications Technology Satellite (ATS-C): Nat'l. Aeronautics and 

Space Adm., Goddard Space Flight Center, X513-67-457. 

--- 1967c, Space tracking and data acquisition network manual: N at'l. Aeronautics and Space Adm., 

Goddard Space Flight Center, X-350-67-304. 

U.S. National Aeronautics and Space Administration, 

Langley Research Center, 1970, NASA 75 project, 

Viking mission definition: Nat'l. Aeronautics and 

Space Adm., Langley Research Center, M75-123-l, 

app. D. 

U.S. National Aeronautics and Space Administration, 

Manned Spacecraft Center, 1963, Mercury project 

summary: Nat'l. Aeronautics and Space Adm., 

Manned Spacecraft Center, SP-45. 

--- 1971, EREP users handbook. 

U.S. National Aeronautics and Sp·ace Administration, 

Manned Sp·acecraft Genter, Earth Observations 

Aircraft Facility, 1970, Aircraft sensor systems 

facility: N at'l. Aeronautics and Space Adm., 

Manned Spacecraft Center, 3v. 

U.S. National Aeronautics and Space Administration, 

Manned Sp·acecraft Center, Earth Observations 

Aircraft Program, 1971, FY 1971, 1st annual report: Nat'l. Aeronautics and Space Adm., Manned 

Spacecraft Center, Off. Space Sci. and Applications. 

Whittlesey, J. H., 1970, Tethered balloon for archaeological photos: Am. Soc. of Photogramm., 

Photogramm. Eng., v. 36, no. 2. 

World Data Center A, 1971, Rockets and satellites 

catalogue of data: N at'l. A cad. of Sci. 

Wyckoff, R. C., 1962, Scientific experiments for Mariner 

R-1 and 4-2: Calif. Inst. of Tech., Jet Propulsion 

Lab. Tech. Rept. 32-315. 

Young, E. F., 1968, Tethered balloons: present and 

future: Am. Inst. of Aeronautics and Astronautics, 

AIAA Paper 68-941. 

35 

ILLUSTRATIONS 
UJ 

0 

:::> 

k ft. km 

165 50 

45 

135 

40 

35 

~ 105 

~ 

_J 

<X: 

75 

45 

100 

NOV. 1970 

~ ~ 0.14X105m3 

~ O.IOX 105 m3 

0.76 Xl0 4 m3 

0. 34 Xl04 m3 

200 600 1000 1400 1800 2200 ki logroms 

1000 2000 3000 4000 5000 pounds 

PAYLOAD 

FIGURE 1.-Payload-altitude capabilities of polyethylene free balloons. 

38 
UJ 

Cl 

::::> 

1-

1-

_.J 

<t 

kft. 

135 

105 

75 

45 

20 

20 

8 

6 

2 

10 

8 

6 

500 

.15XI06 m3 

'.45X 10 5 m3 

.69X 105 m3 

.33 x 105 m3 

NOV. 1970 

2000 4000 6000 kg. 

3000 7000 11,000 15,000 lb. 

PAYLOAD 

FIGURE 2.-Payload-altitude capabilities of scrim free balloons. 

39 
FIGURE 3.-Sunrise inflation of a 23,000-m' polyethylene balloon. 

FIGURE 4.-A tandem balloon system reeled up in preparation for launch. 

40 
Q) 

0 

E 

-II) 

LLI 

...... 

en 

0 

u 

z 

0 

0 

...J 

...J 

<t 

CD 

$300,000 

$200,000 

$100,000 

$10,000 

BALLOON COST vs VOLUME 

(BALLOON ONLY) 

SCRIM 

DEVELOPMENT OF 

NEW SYSTEM 

POLYETHYLENE 

I JULY 1970 

$ I ,000 L___-L.____u_:..~~__J__J_..LL_ _ __L_____JL-J.____L_..L-L.L.LL--L______l___-L_JL___L_L....L.J.....J__ ___ _ 

IXI03 IX10 4 IXI0 5 IXI06 cubic meters 

I I ,I I I II 

IXI0 5 IXI06 10XI0 6 IOOX 10 6 cubic feet 

BALLOON VOLUME 

FIGURE 5.-Cost estimates for polyethylene and scrim free balloons. 

41 
F'IGURE 6.-Typical stratospheric wind fiOIW at 37 km (120,000 ft) during midsummer. 

FIGURE 7.-First approximation of areas in the Northern Hemisphere 

where balloon hovering and boomerang drifts are feasible during summer within the altitude range 14 to 22 km. 

42 
70 

--

~ 

65 LLJ 

0 

::::> 

1- 60 

1-

_.J 

<{ 

55 

12 

-DAY I 

--·DAY 2 

••• .. DAY 3 

X 

X 

X 

X 

X X XX DAY 4 ., ... 4 ••• 

~ ··. X 

X 

__ ..,, 

, . , ·. 

, 

/ 

" 

•• • • • • • • • • • • • •• • .I X X X X 

X 

X 

X 

12 

PACIFIC DAYLIGHT TIME 

00 12 

16 ----- ;' ' / I 

, " / , 

/ 201-

/ I 

/ -~ I 

, - """'-, lc:c -- " ....._, ., ., l~ .......... toa···. 00 I _: 

... ····· / .· ~ , "'··. ..... . ..·: , ... ----- ~ : .. .. ,"" • A •. 

•• / .;.12 ••• 16 ~ ~ ~ '-

• _, 04 . _, .......... .:.- ... ..-

· .. . 

.. . 

··.. . . ~ ..... . 08 

. .~ 

. . 

. 

. . 

40nm 

. . . .... 

FIGURE 8.-Hovering balloon flight C70-18 launched from Chico, Calif., August 17, 1970. Flight 

duration, 72 hours. 

43 
,;.. 

,;.. 

FIGURE 9.-Project Stratoscope II carrying a 3-ton optical telescope to an altitude of 24,400 m (80,000 ft). Its observations 

yielded much valuable astronomical data. 

FIGURE 10.-The Stratoscope II telescope with guidance package and highresolution camera equipment. 
w::.. 

<:Jl 

~ 

-'-

FIGURE 11.-A 710-m' spherical tethered balloon being prepared for launch at the White Sands Missile 

Range, N.Mex. 

FIGURE 12.-Single-hull British Ashape kite balloon with a volume 

of 2,800 m'. 
kft 

2832 m3 volume (I 00,000 ft 3 ) 20 km A, 

6 B, 2000m 3 II ( 70,600 ft 3

) 

c, 1274m 3 II (45,QOOft 3

) 

5 Altitudes attainable in calm winds 15 

4 

~ 

0 

~ 10 3 ..... 

~ <t 

2 

5 

200 400 600 800 1200 kg 

PAYLOAD 

400 800 1200 1600 2000 2400 2800 3200 lbs 

FIGURE 13.-Payload versus altitude for British barrage balloons. 

46 
FIGURE 14.-Walking the balloon and aerial 

camera to the target area (Turkey). 

47 

FIGURE 15.-The radio-controlled Hasselblad 

EL 500 camera hung in its gimbal as seen 

from below. 
FIGURE 16.-Cessna 180 Skywagon. 

FIGURE 17.-Beechcraft Bonanza A36. 

FIGURE 18.-Cessna 337 Turbo-System Super Skymaster. 

48 
FIGURE 19.-Beechcraft Queen Air B80. 

FIGURE 20.-The Grumman OV-1 Mohawk observation aircraft. 

49 
FIGURE 21.-Lockheed Y0-3A quiet reconnaissance aircraft. 

50 
FIGURE 22.-RockweU Standard Jet Commander 1121. 

FIGURE 23.-Gates Learjet 24. 

FIGURE 24.-Fairchild Hiller Porter. 

51 
KA62 

MULTI BAND 

CAMERAS (4) 

.4 GHz 

SCATTEROMETER 

APN 159 

ALTIMETER 

1.6 GHz 

RS-14 

1-R SCANNER 

FIGURE 25.-NASA 927 Lockheed NP3A Orion flight configuration. 

FIGURE 26.-Douglas Skywarrior RA-3B. 

52 
FIGURE 27.-Lockheed NC130B (RC130) Earth Resources Aircraft (NASA 929) . 

Navigator's 

Stoti<>n 

Prime 

Camero 

Inertial 

Reference 

Prime 

Camero 

FIGURE 28.-Boeing RC135A. 

Terrain Profile 

Recorder 

Antenna 

FIGURE 29.-Isometric view of Boeing RC135A showing the USQ-28 aerial electro-photomapping 

system. 

53 
FIGURE 30.- E-Systems L450S reconnaissance aircraft in piloted configuration. 

FIGURE 31.-North American Rockwell X15· research aircraft. 

FIGURE 32.-General Dynamics/ Martin RB57F. 

54 
Ol 

Ol 

/---Electronics 

tD Camera Systems and Data Annotation 

.. Forward-Looking Radar 

-ELRAC 

ffiB Infrared Reconnaissance Set 

fim Communications (HF, UHF, IFF , TACAN and ADF) 

E::!J Side-Looking Radar 

~-------Fuel and Englnes---------- - -to>----

-1 

FIGURE 33.-McDonnell Douglas (Phantom II) RF-4C'. 

FIGURE 34.-RF-4G flight configuration. 
FIGURE 35.-Lockheed U-2. 

- FIGURE 36.-Lockheed SR71A strategic reconnaissance aircraft. 

56 
FIGURE 37.-USDA Forest Service Bell Heliwpter fire spotter, Model 47G-3B-1. 

FIGURE 38.-Northrop Falconer surveillance drone. 

57 
FIGURE 39.-Goodyear blimp Columbia. 

WElt 

FIGURE 40.-Television camera mounted on blimp Mayflower. 

58 
FIGURE 41.-Schweizer sailplane SGS 2-32. 

REENTRY VEHICLE 

ATTITUDE REFERENCE SYSTEM I 

(STELLAR CAMERAS) 

POSITIONAL DATA 

(DOPPLER) 

METRIC CAMERAS 

FIGURE 42.-Sketch of proposed film-return Earth-sensing space vehicle 

(USGS) . 

FIGURE 43.- Aircraft recovering a capsule such as might contain film from an 

Earth-sensing spacecraft. 

59 
0') 

0 

YAW NOZZLE 

SOLAR PADDLE -----\11\-\ 

INlERCONNECTING TRUSS ------=m:Jl"'.ll.ll..-+-t'\\11 

FILTER WEDGE SPECTROMETER~ 

SELECT IVE CHOPPER RADIOMETER 

MON ITOR OF ULTRAVIOLET 

SOLAR ENERGY (MUSE) 

S- BAND ANTE 

GRAVITY-GRADIENT BOOM 

(EXTENDED) 

DIRECTION IN ORBIT 

---

S- BAND ANTENNA 

FRARED INTERFEROMETER 

SPECTROMETER 

IN TERROGATION RECORDING 

AND LOCATION SYSTEM ANTENNA 

TEMPERATURE / HUMIDITY 

INFRARED RADIOMETER 

SATELLITE INFRARED SPECTROMETER 

FIGURE 44.-Nimbus D satellite (sketch) . 

MOMENTUM 

WHEEL 

MIRROR 

BASEPLATE 

REAL-TIME 

ANTENNA 

SEPARATION 

RING 

//- THERMAL FENCE 

OUTER RING 

' COMMAND 

AND 

BEACON ANTENNA 

FIGURE 45.-TIROS M spacecraft. 
0') 

,..... 

FIGURE 46.-Earth Resources Technology Satellite (ERTS). 

~ 

COMMAND 

AND 

TRACKING 

FIGURE 47.-Sketch of ERTS system. 

AND 

TRACKING DATA 
NF~:~~i~~1~~~ ~~K'----ff;"' 

VERY HIGH 

FREQUENCY REPEATER----

~~~tcE:a~~::E;RREE~~~~~~ ----

TELE'.\ETRY AND COMMAN[ UNITS 

EXPERIMENT- --

SUB-SYSTEM --

- - NUTAT ION SENSOR 

HYDROGEN PEROXI DETANKS 161 

I" A" SYSTEM 111"8" SYSTEM 41 

ENVIRONMENTAl 

MEASUREMENT 

EXPERIMENT IEMEl 

JET 

FIGURE 48.-ATS-B systems and interior experiments. FIGURE 49.-ATS-B exterior experiments. 

FIGURE 50.-Concept of ATS-F&G. 

62 
a;, 

~ 

FIGURE 51.-Synchronous Meteorological Satellite ( SMS). 

SATELLITE POSITIONS (SIX) 

\ 

STEREO 

EQUATOR or 

.......---- ECLIPTIC -----+-

EARTH 

\ 

I \ 

1-4--------46,000 N.MI. ------~ 

FIGURE 52.-Sehematic drawing of a 6-satellite high-resolution geosynchronous 

Earth-sensing system. 
FIGURE 53.-Ranger lunar probe. 

FIGURE 54.-Lunar Orbiter spacecraft (artist's con- FIGURE 55.-Lunar Orbiter E, showing camera lens. ception.) 

64 
HIGH- GAIN 

ANTENNA 

OMNIDIRECTIONAL --......... 

ANTENNA A 

RADAR ALTITUDEDOPPLER VElOCITY 

SENSOR 

VfRNIER 

PROPELLANT 

TANKS 

ATTITUDE CONTROL 

GAS TANK 

(NITROGEN) 

SOLAR PANEL 

ALPHA SCATTERING 

INSTRUMENT ELECTRONICS 

CANOPUS STAR SENSOR 

OMNIDIRECTIONAL 

ANTENNA B 

J 

VERNIER PROPELLANT 

PRESSURIZING GAS 

TANK (HELIUM) 

FIGURE 56.-Surveyor lunar lander. 

FIGURE 57.-Mariner 4 spacecr aft (flyby 

version) . FIGURE 58.-Mariner 9 spacecraft (Mars Orbiter) . 

65 
FIGURE 59.-Viking spacecraft. 

66 
FIGURE 60.-Pioneer spacecraft. 

FIGURE 61.-Mercury, Gemini, and Apollo spacecraft. 

67 
FIGURE 62.-Apollo service module, showing Scientific Instrument Module (SIM). 

ALEM DATA SYSTEM 

X-RAY & ALPHA 

PARTICLE SPECTROMETERS 

TV 

camera 

L.C.R.U. 

camera 

Magaetometer 

stowage bags 

FIGURE 64.-Sketch -of Lunar Rover Vehicle, showing instruments. 

31N. MAPPING CAMERA 

OPTICAL BAR 

PANORAMIC CAMERA 

EVA HANDLES 

20 FT RETRACTABLE BOOM 

MASS 

SPECTROMETER 

GAMMA RAY 

SPECTROMETER 

25 FT RETRACT ABLE BOOM 

FIGURE 63.-Sketch of instruments carried in Apollo SIM bay. 

68 
69 
-.::) 

0 

t 

' ATM 

MULTIPLE DOCKING 

ADAPTER 

AIRLOCK MODULE 

DRY WORKSHOP 

5/14/73 

I 

SL-1 

J 

.~ COMMAND ! ' l SERVICE 

\MODULE ~ 

~:r) 1 

A 

~ 

+ 

COMMAND 

SERVICE 

MODULE~ 

11 

~ 

+ t 6/24/73 l 9/25/73 

5/27/73 

I 

SL-2 

7/28/73 

I 

SL-3 

COMMAND 

SERVICE 

} MODULE ~ bd ·'V!f> 

I 

' 

r 

11/11/73 

I 

SL-4 

' APPROXIMATELY 56 

(or up to 70} DAYS 

AFTER LAUNCH 

FIGURE 66.-Skylab-A, activatiJon and operation-periods of occupancy. 
71 
...:) 

tv 

1960-63 

TIROS R&D MISSION 

TIROS I 

• Television Feasibility 

• Infrared Experiments 

• Narrow and Wide-Angle 

Television 

TIROS II 

• Magnetic Torquing 

• Narrow and Wide-Angle 

Television 

TIROS III 

• Limited Operational Use 

• University of Wisconsin 

Radiometer 

• NASA Radiometer 

• Wide-Angle Television 

TIROS IV through VI 

• Limited Operational Use 

• Wide-Angle Television 

TIROS VII 

• Limited Operational Use 

• Ion Temperature Probe 

• NASA Radiometer 

• Wide-Angle Television 

TIROS VIII 

• First Use of APT 

Real-Time Television 

Readout 

• Wide-Angle Television 

1965-66 

TIROS WHEEL 

TIROS IX 

• First Wheel Mode 

Spacecraft 

• Near-Polar Sun-Synchronous 

Orbit For Daily 

Global Observation 

• Forerunner of the TIROS 

Operational System 

• Wide-Angle Television 

TIROS X 

• Interim Operational 

Satellite 

• Wide-Angle Television 

ESSA 1 

• Operational Satellite 

• Wide-Angle Television 

1966-69 

APT AVCS 

TIROS OPERATIONAL SYSTEM 

ESSA 2, 4, 6 and 8 

• APT Spacecraft For 

Real-Time Global 

Readout 

ESSA 3! 5, 7, and 9 

• AVCS Spacecraft For 

- Daytime Global TV 

Observation 

- Remote Sensing and 

Storage for u.s. 

Readout 

• S-Band Transmission From 

ESSA 7 and 9 

FIGURE 68.-Evolution of TIROS, TOS, ESSA satellites. 

1970-73 

THE IMPROVED TIROS 

OPERATIONAL SYSTEM 

TIROS M and ITOS A, B, and C 

• Daytime Global APT 

Readout 

e Daytime Global AVCS 

Readout 

• Day and Night Real-Time 

and Remote IR and 

Visible Channel Scanning 

Radiometer 

• Solar Proton Monitor 

• Flat Plate Radiometer 

• Earth-Stabilized 

Platform With 

Growth Capability 

For Future Sensors 

• ITOS 1 (formerly TIROS M) 

launched January 23, 1970 

• NOAA 1 (formerly ITOS A) 

launched December 11, 1970 

ITOS D,E,F, and G 

• Scanning Radiometers and 

Very High Resolution 

Radiometers For Day and 

Night Real-Time and Remote IR and Visible DataGlobal Coverage 

• Vertical Temperature 

Profile of Atmosphere 

• Solar Proton Monitor 
ESSA 3 

(AVCS TYPE) 

ESSA 4 

(APT TYPE) 

FIGURE 69.-TIROS Operational Satellites (TOS). 

FIGURE 70.-lnterior of the Environmental Survey Satellite, ESSA 3. 

73 
FIGURE 71.-NOAA Satellite ITOS. 

74 
VERY HIGH 

RESOLUTION 

RADIOMETERS 

S-BAND 

MOMENTUM 

WHEEL 

ACTIVE THERMAL. 

CONTROL.LE R LOUVERS 

SOLAR PANEL 

DEPLOYMENT 

VTPR CALIBRATION PORT 

COMMAND AND 

BEACON ANTENNA 

RADIOMETERS 

VERTICAL TEMPERATURE 

PROFILE RADIOMETERS 

FIGURE 72.-NOAA Satellite ITOS-D. 

75 

REAL-TIME 

ANTENNA 

·:.· u.s. GOVERNMENT PRINTING OFFICE: 1974-543-SBt/ 65