CONGRESS OF THE UNITED STATES

CONGRESSIONAL BUDGET OFFICE

CBO

Recent 

Development 

Efforts for 

Military Airships

NOVEMBER 2011
Pub. No. 4239
The Congress of the United States O Congressional Budget Office

CBO

Recent Development Efforts for 

Military Airships

November 2011
CBO

Notes and Definitions

The cover shows a U.S. Navy MZ-3A manned airship landing at Lake Front Airport, New Orleans, Louisiana, provide support for the Deepwater Unified Command and the Gulf of Mexico oil spill. Photo by Mass CommunSpecialist 2nd Class Andrew Geraci.Aerostat: A tethered, unmanned airship.Airlift: The transportation of people, equipment, or other cargo by air.Airship: An aircraft that obtains buoyant lift from a contained volume of helium or other gas that is less dense t

surrounding air. Also referred to as a lighter-than-air vehicle.Conventional Aircraft: An aircraft that does not rely on buoyant lift to achieve flight. In this document the ter

includes fixed-wing aircraft, tilt-rotor aircraft, and helicopters.Conventional Airship: An airship that uses only buoyant lift to achieve flight.Envelope: The external structure of an airship within which the helium or other buoyant gas is located. There acategories of envelopes: rigid, semirigid and nonrigid. Rigid envelopes use an internal frame to keep their shapeSemirigid envelopes use a “keel” along the bottom of the envelope to distribute weight. Nonrigid envelopes havframe and use only gas and envelope design to keep their shape.Hybrid Airship: An airship that uses a combination of buoyant lift from helium, aerodynamic lift from the shapenvelope, and variable-direction thrust (more commonly called vectored thrust) to stay aloft.Intelligence, Surveillance, and Reconnaissance (ISR): Reconnaissance operations observe an area to collect information. Surveillance is the systematic observation of a particular area. Intelligence is the product of surveiland reconnaissance once the information from those operations has been analyzed and evaluated.Orbit: In this document, orbit refers to the region in the sky in which an aircraft operates while it is observing activities below. In military parlance, an aircraft orbit is often called a combat air patrol, or CAP.Payload-duration: Payload-duration is the weight (payload) that could be carried to a location multiplied by th

amount of time it could remain there (duration).
Preface

CBO

Airships—also known as lighter-than-air vehicles—have been proposed as alternatives to some of the aircraft thDepartment of Defense uses today for two types of missions: intelligence, surveillance, and reconnaissance; and The unique characteristics of airships offer some advantages and disadvantages for those missions relative to aircurrently in the fleet. At the request of the Chairman of the Senate Armed Services Committee, the Congressional Budget Office (CBexamined the Department of Defense’s plans and proposals for airships. In keeping with CBO’s mandate to proobjective, impartial analysis, this study makes no recommendations.Alec Johnson, formerly of CBO’s National Security Division, prepared the document, with assistance from DavArthur, under the general supervision of David Mosher. The line drawings of airships were done by Bernard KemCharles Whalen of CBO provided helpful comments on the report, as did Mark T. Lewellyn of the Johns HopUniversity Applied Physics Laboratory. The assistance of an external reviewer implies no responsibility for the fproduct, which rests solely with CBO.Jeanine Rees and John Skeen edited the document. Maureen Costantino and Jeanine Rees prepared the study fpublication, and Maureen Costantino designed the cover. Monte Ruffin printed the initial copies, and Linda Sccoordinated the print distribution. This publication is available on CBO’s Web site (www.cbo.gov).

Douglas W. Elmendorf 

Director

November 2011

CBO

Exhibit 

List of Exhibits

1. Illustrations of Airships 2. Wind Speed and Location, Altitude, and Time of Year 3. General Characteristics of Airships Under Consideration by DoD 

Low-Altitude Intelligence, Surveillance, and Reconnaissance

4. Low-Altitude Airships for Intelligence, Surveillance, and Reconnaissance 5. Payload, Endurance, and Speed of Low-Altitude Airships and Fixed-Wing Aircraft 6. Payload-Duration of Low-Altitude Airships and Fixed-Wing Aircraft 

High-Altitude Intelligence, Surveillance and Reconnaissance

7. High-Altitude Airships for Intelligence, Surveillance, and Reconnaissance 8. Payload, Endurance, and Speed of High-Altitude Airships and Fixed-Wing Aircraft 9. Payload-Duration of High-Altitude Airships and Fixed-Wing Aircraft 

Airlift

10. Proposed Airships for Airlift 11. Approximate Performance Characteristics of Proposed Airships for Airlift 12. Airlift Performance for an Illustrative Deployment to the Middle East 13. Illustration of the Number of Aircraft Needed to Provide 1,000 Tons per Day Throughput Within a Theater of Op
CBO

Recent Development Efforts for 

Military Airships

During the past decade’s operations in Afghanistan and Iraq, the U.S. military has come to rely heavily on the continuous or nearly continuous presence overhead of both manned and unmanned aircraft to support ground troops. Unmanned aircraft that remain aloft in particular locations (or “orbits”) have been primarily used to provide timely information about activities on the ground and to attack ground targets on short notice. Most prominent among these aircraft are the Department of Defense’s (DoD’s) fleets of unmanned Predators, Reapers, and Global Hawks; however, satellites and manned conventional aircraft, including fighters and long-range bombers, have also contributed. The demand for those so-called “persistent” or “loitering” missions has led the Air Force to substantially enlarge its fleet of unmanned aircraft, and the Army, Navy, and Marine Corps to field or plan to field similar aircraft to provide intelligence, surveillance, and reconnaissance (ISR) and light-attack capabilities of their own.1 Unmanned 

aircraft are particularly attractive for such missions because they can be designed to provide durations beyond the physical endurance of human air crews and because they do not put humans at risk during operations in potentially hostile airspace.

In light of the demand for aircraft capable of remaining aloft for long periods of time, considerable interest in airships as alternatives to conventional aircraft exists. Although unmanned airships are unproven, they have the potential to remain in the air for long periods—providing mission durations that are many times longer than would be practical for conventional aircraft. Consequently, the military services are exploring a variety of designs for unmanned airships capable of carrying ISR sensors.The technology needed to field airships for ISR could also be applied to airships meant for airlift—that is, for the transportation of people, equipment, or other cargo. Whether airships designed to carry cargo would be manned or unmanned would depend on the specific missions they performed. Although the military services’ investment in developing airships for airlift has been limited, several private companies are exploring potential designs or are in the process of building prototypes.In this document, the Congressional Budget Office (CBO) examines the potential capabilities of airships for ISR and airlift missions. In brief, CBO finds that:

B If the speed, payload, and endurance proposed 

for unmanned airships can be achieved, the 

resulting craft couland airlift roles;

B Airships’ performa

provide some advadisadvantages relattional aircraft currmissions; and

B Airships would pre

lenges such as greaconditions and the types of maintenan

Because the developmfor modern military amost cases cost estimative; therefore, CBO dairships here. Althougcapabilities of airships assessing cost-effectivecosts as various techn

BackgroundAirships were among military service. Germmaritime patrol missifirst zeppelin bombinstaged in early 1915. 

1. See Congressional Budget Office, Policy Options for Unmanned Aircraft Systems (June 2011).
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INTRODUCTION RECENT DEVELOPM

Navy operated a variety of airships for maritime patrol and fleet reconnaissance. The best known of those were the large rigid-framed airships—such as the U.S.S. Shenandoah and the U.S.S. Akron

—

built in the 1920s and early 1930s. In commercial service, airships were used for the first regularly scheduled passenger flights across the Atlantic in the early 1930s, several years before fixed-wing aircraft. Airships were attractive during the early days of military aviation because, with buoyancy provided by hydrogen or helium, the engines needed only enough power to move the aircraft at relatively low speed, and airframes needed only enough strength to support their own weight and to withstand the relatively mild stresses associated with low-speed flight. Fixed-wing aircraft, in contrast, required stronger airframe structures and more powerful and reliable engines because their lift is derived from pushing wings through the air at high speed. Rapid improvements in airframe design, airframe materials technology, and aircraft engines during World War II largely overcame the shortcomings of fixed-wing aircraft. Moreover, improvements in antiaircraft weapons during and after the war led military planners to conclude later that airships would be too slow and too vulnerable to attack from the ground, particularly when facing a technologically capable adversary such as the Soviet Union. Therefore, interest in airships waned.The end of the Cold War, however, ushered in an era in which operations against less capable adversaries have been more common. In Iraq and Afghanistan during the past decade, for example, air defenses have been essentially nonexistent, 

allowing aircraft with limited self-defense features—in particular, the fixed-wing MQ-1 Predator and MQ-9 Reaper unmanned aircraft—to operate effectively in nearly uninterrupted flights over unsecured territory. The nature of the conflicts in those countries and elsewhere has placed an emphasis on persistently remaining aloft to provide ISR and limited missile attacks against ground targets. The Department of Defense is exploring the use of airships for long-endurance missions such as those.2 Although DoD’s current focus is on 

airships for ISR, there have been proposals for equipping airships with weapons as well.Using airships for airlift has also periodically stirred interest in military circles. In particular, concern arose during the 1990s that rapid deployments by air, like those to the large airbases in Saudi Arabia during the first Iraq war, would not be possible in a future conflict if such airbases were not available. Transport airships capable of landing in any suitably large open area, proponents argued, could reduce the military’s dependence on overseas bases. Although advocates of airships suggested designs capable of carrying payloads many times larger than those of the largest fixed-wing aircraft, work 

on such aircraft did ndesigns or small-scale Modern airships and usually limited to altiderive some or all of thhelium gas contained ture, or envelope. Theenvelope: rigid, semirenvelopes use an interearly airships such as rigid envelopes. Semiralong the bottom of tweight. Nonrigid airsonly gas and envelope The blimps frequently events are usually nonearly airships, which hing fire because they uenvelopes (hydrogen)exclusively use helium (But even helium-fillebeing lost to fire if othburn.) Conventional airshipsnonrigid, achieve flighhelium alone. “Hybriinnovation, use a comhelium, aerodynamic envelope, and variablemonly called vectored combination of three hybrid airships to carrpayloads) for a given vprovides a greater abil

2. Of course, circumstances will not always permit those 

types of missions. In the 1991 Iraq war and in operations over the former Yugoslavia later in the 1990s, for example, it was possible to attack or otherwise suppress air defenses to the point at which fighters and bombers could operate in relative safety. However, the suppression of air defenses in those conflicts was probably insufficient to allow aircraft such as Predators or airships to orbit continuously overhead.
CBO

INTRODUCTION RECENT DEVELOPM

on the aircraft than is the case with conventional airships that rely on buoyancy alone.Today, the Navy is using a conventional, nonrigid airship—the MZ-3A—to experiment with potential airship payloads and explore how airships might be used in actual operations. The Army, Air Force, and the Defense Advanced Research Projects Agency (DARPA) are working on designs for other airships, with a primary focus on unmanned craft for ISR. Other organizations within DoD—for example, the Missile Defense Agency and the Joint Improvised Explosive Device Defeat Organization—have made investments in airship technologies as well. Over the past two years alone, DoD has funded more than $500 million for projects related to lighter-than-air platforms, and additional spending is planned for the future.Other government agencies such as the Department of Homeland Security and the National Aeronautics and Space Administration also have explored or are exploring potential designs and uses for airships, albeit at lower funding levels than DoD. Additionally, several privately funded development efforts are under way that could yield airship designs suitable for adoption by DoD.Intelligence, Surveillance and Reconnaissance (ISR)The ISR missions of the type common in Afghanistan and Iraq have been characterized by the desire for nearly continuous aerial presence, the need for 

only modest payloads to accommodate the appropriate sensor packages, and nearly or totally absent air defenses. Under such circumstances, the performance characteristics of airships offer some significant advantages but also have various disadvantages when compared with those of the fixed-wing aircraft and space satellites that the Department of Defense currently uses to meet its needs for aerial ISR.

Performance of Airships Relative to Other AircraftUnmanned airships have the potential to perform ISR tasks with greater efficiency than conventional unmanned aircraft systems. Because unmanned airships could remain aloft for much longer periods than conventional aircraft, maintaining continuous ISR orbits with a smaller number of aircraft might be possible. Airships may also offer greater basing flexibility than conventional aircraft because airships could operate without the need for a long runway. However, airships would probably offer less flexibility to operate in poor weather conditions. High winds can make airships difficult to control, especially when near the ground, and the increased fuel consumption that would be needed to remain over one area in the face of high winds could significantly reduce an airship’s time on station.Like other unmanned aircraft besides stealth ones, ISR airships would probably be primarily used in secure airspace. If, however, airships encountered air defenses, their survival would depend on the specific circumstances of the engagement. Relative 

to a fixed-wing aircrafHawk, airships operat60,000 feet or higher) detect by adversaries lor radar reflections beto be quiet and cool astructure made of radtle rigid structure for also be out of range foor guns. In contrast, aaltitudes would probaconventional aircraft their lower speed and detected, those airshipground fire than smalcraft, but they might damage. For examplemakes them less suscethat can cause convenflight when damaged, lopes rely on just a sligambient atmosphere, holes that are not too Because airships sacrifendurance relative to might offer less flexiblocation of ISR orbits cumstances on the gro

threats materialized in ment, airships would area and reach safe airalso reduce search ratecover very large areas. rate—the area covered 
CBO

INTRODUCTION RECENT DEVELOPM

that is theoretically defined as the product of the aircraft’s speed and the sensor’s detection range to either side of the flight path—is lower for lower speeds.) Such a limitation, however, would be less significant for missions calling for close observation of smaller areas.Performance of Airships Relative to SatellitesAirships can employ much less sophisticated and less costly sensors than satellites use. Because airships operate at a much lower altitude, they can employ smaller, less sensitive antennas for detecting electronic emissions and smaller, less capable optics for a given image resolution. Also, sensors for use on airships would not need to operate for their entire lives without maintenance or repair, as satellite sensors must. Moreover, satellites are limited to the sensors that they are carrying when they are launched, but the type of sensor carried by an airship could be selected on a mission-by-mission basis, and improved sensors could be used as they became available.Airships can be continuously located wherever ISR is needed (subject to the constraints of weather, air defenses, and otherwise restricted airspace), while satellite observations are limited to when orbits pass overhead. Satellites, however, have the advantage of a very large field of view because of their great distance above the ground. Additionally, although satellites fly in predictable Earth orbits that can be easy to track, they are very difficult to attack. Also, satellites are free of airspace restrictions.

Other FactorsAdvances in airship technology have not been tested in actual operations, and considerable risks remain for modern airships relative to conventional unmanned aircraft systems. Many of the technologies needed for critical systems—propulsion and power, fabric for airship envelopes, flight control systems, and sensors able to operate for weeks or months without maintenance—are in the early stages of development. Furthermore, the military has little contemporary experience in airship operation, maintenance, and support. Concerns include storage of the gas needed to fill airships; storage of the vehicles themselves; maintenance of the vast areas of fabric from which airships’ envelopes are constructed; and safe ground maneuvering, especially in the presence of winds.Cost is another crucial issue. Some proponents have asserted that airships could cost less to purchase and operate than satellites or other aircraft. Those advocates cite, for example, the significantly lower fuel consumption of airships relative to fixed-wing aircraft. The costs of airships remain unknown, however, because technology is at an early stage of development and the details of purchases, operation, maintenance, and support are yet to be determined. For example, the cost of obtaining large volumes of helium and the equipment needed to store and distribute it to combat theaters around the world is unclear.3 Because of 

such uncertainty, cost estimates would be highly speculative. In this document, therefore, CBO does not examine the costs of airships relative to other types of aircraft and satellites.

AirliftAlthough most currenplatforms, airships comove cargo—equipmwithin or between comships would probably airlift because they prgas volume and they cnear the ground, partunloading, when the plus cargo) changes suAirships would have smeans of transportatilikely to rely on fixed extent than conventiobases, and ships, whictherefore, could delivethat lack such facilitieposed designs prove teairships would be able loads than fixed-wing destination more quicif airships prove to be ponents assert, airshipsubstantially lower co3. Indeed, some reports i

encountered challengedistribution demands resulted from the wideprovide security surveideployment of much lincrease the demand flenges can most likely of doing so has not be
CBO

INTRODUCTION RECENT DEVELOPM

advantage that would grow if fuel prices increase. (Fuel for transport aircraft represented nearly 40 percent of the Air Force’s energy costs in fiscal year 2009.) Savings from lower fuel consumption, however, could be offset by costs that have not yet been identified or quantified. Proposals have been put forward for hybrid airships that could accommodate payloads of various sizes. Airships carrying 20 tons (about the payload of a C-130 intratheater airlift aircraft) could operate independently of runways and only slightly more slowly than helicopters but with substantially larger payloads. Airships carrying 50 tons (about the average payload of a C-17 intertheater airlift aircraft) or more could complement today’s strategic airlift aircraft and sealift ships. Very large cargo airships capable of carrying a few hundred tons would offer greater payloads but lower speed than 

conventional cargo aircraft provide and lesser payloads but greater speed than cargo ships provide. The feasibility of constructing and operating such enormous aircraft—by some estimates, about 1,000 feet in length and 300 feet in width for a 500-ton capacity airship—remains in doubt, however.Other risks remain in using airships for airlift. Airships would still have the disadvantages discussed above for ISR missions, such as greater sensitivity to weather conditions. As with other types of airships, those used for tactical airlift (airlift within a theater of operations) would be vulnerable to hostile fire if required to fly over unsecured territory. Those airships would operate at similar altitudes and not dramatically lower speeds than helicopters, but they would be much less maneuverable and thus less able to avoid 

threats. Furthermore, demonstrate sufficienoperations before they tain continuous flows Whether or not airshiadditions to the militairlift over intercontindepend in part on the cal development as weoperation costs relativaircraft. The future of depend on whether thdeliveries before ships whether there is a neelocations that cannot ing transportation sys
RECENT DEVELOPM

CBO

Exhibit 1.

Illustrations of Airships

Source: Congressional Budget Office based on data provided by manufacturers.Note: ISR = intelligence, surveillance, and reconnaissance; ISIS = Integrated Sensor Is the Structure; 

HALE-D = High-Altitude Long-Endurance Demonstrator; LEMV = Long-Endurance Multi-Intelligence Vehicle.

HALE-D 

(Technology demonstrator) 

ISIS (Technology demonstrator)

ISIS (Full scale; proposed)

High-Altitude ISRLow-Altitude ISRAirlift

Reference Vehicles

Project Pelican 

(Technology Demonstrator)

HiSentinel

(Technology demonstrator)

SkyTug

LEMV

LEMV-Heavy (Proposed)

(Feet)

0 100 200 300

Blue Devil Block II MZ-3A

 Star Light

High Altitude 

Shuttle System

747-400

Nimitz Class Aircraft Carrier

Goodyear

Airship programs ththat are being pursumaturity: Some are are being developed feasibility, and a few established technolput to use in the fieCongressional Budairships designed foand reconnaissance airlift of cargo. Thethat of a Goodyear an aircraft carrier. Caerostats—tetheredmonly used for obsThe airships discusthree operational relow-altitude ISR, andesigns, including bmodels intended to full-scale aircraft caoperations, show aition at high altitudis preferred when laviewing ranges are looking deep within remaining outside ihigh-altitude vehicland two—the Star LShuttle System—ar(Upon completion detaches from the gbase, and the envelodesigns show aircraaltitudes. Full-motimonly carried by thISR aircraft flown tbe used on airships tudes. Finally, three proposed for the tr
RECENT DEVELOPM

CBO

Exhibit 2.

Wind Speed and Location, Altitude, and Time of Year

Sources: National Oceanic and Atmospheric Administration and U.S. Air Force.Note: NOAA = National Oceanic and Atmospheric Administration; ESRL = Earth System Research Laboratory.

60°

East

120°

East

120°

West

60°

West

180°

NOAA/ES2L Physical Science Division

Average Wind Speeds at 40,000 Feet Above Sea Level (Knots)

90° South60° South30° South

Equator

30° North50° North90° North

30 40 50 60 70 80 90

Jan. Mar. May July Sept. Nov.

0

0.20.40.60.81.0

18,000 Feet

24,000 Feet

68,000 Feet

0

20,00040,00060,00080,000

100,000

0 10 20 30 40 50 60 70

Average Speed (Knots)

(Altitude in feet) (Fraction of time wind exceeds 40 knots)

Average Wind Speeds (Kabul, Afghanistan) Seasonal Wind Speed (Baghdad, Iraq)

Because airships arweight, and use smwould be affected bthan are the convenused by the militarcould be, at best, dworst, destroyed by ground during launmaintaining positiowinds would increathus reduce an airshships might not be all if winds were toAirships’ difficultieconstrain their operand above 60,000 fspeeds tend to be gtudes. High winds especially prevalent latitudes, which incinterest to today’s moperating at high athrough intermedianot necessarily a hawinds could be stroship off course. Conwould be needed to ship to its orbit locAverage wind speed obscure the fact thatially at a given placyear. For example, tering winds in excBaghdad is consideber to May than it Such variations meof airships over a gi

difficult or even imtime. 

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RECENT DEVELOPM

CBO

Exhibit 3.

General Characteristics of Airships Under Consideration by DoD

Source: Congressional Budget Office.Note: DoD = Department of Defense; ISR = intelligence, surveillance, and reconnaissance.

Mission

Operating Altitude

Airship Type

Altitude (Feet)

Endurance or Range

Status of Technology Characteristics

ISR

Low Altitude

Conventional Up to about 

20,000

100 to 300 hours

One system currently operating; others under construction

Relatively mature technology

Hybrid Up to about 

20,000

500 hours Technology 

demonstrations ongoing

Uses static lift from helium, aerodynamic lift from the shape of the envelope, and vectored thrust to stay aloft

High Altitude

Conventional 65,000 to 

75,000

Greater than 400 hours

Technology demonstrations ongoing

Very large envelope volume to sustain lift

PayloadReturn 65,000 to 75,000 100 to 300 hours Technology demonstrations 

ongoing

Payload is detachable and returns to point of origin; airship is single-use

Airlift Low Altitude

Hybrid 9,000 to 

12,000

Hundreds to thousands of miles, depending on design

Technology demonstrations ongoing

Uses static lift from helium, aerodynamic lift from the shape of the envelope, and vectored thrust to stay aloft

Commercially prodat various stages of ber of companies aNorth America invmanufacture. Analyited to airships desirecently funded by (DoD) and to selecairlift.As a result of EarthISR missions for airas either low-altitudoperating at less ththan 60,000 feet, rbetween 20,000 anable for airship opestronger winds that those altitudes. If tfor ISR missions prwould be able to reventional aircraft, wmore than 100 hoube undertaken only 
CBO

Low-Altitude Intelligence, 

Surveillance, and Reconnaissance
LOW-ALTITUDE INTELLIGENCE, SURVEILLANCE, AND RECONNAISSANCE RECENT DEVELOPM

CBO

Exhibit 4.

Low-Altitude Airships for Intelligence, Surveillance, and 

ReconnaissanceSource: Congressional Budget Office based on data provided by manufacturers.Note: LEMV = Long-Endurance Multi-Intelligence Vehicle; BD2 = Blue Devil Block II.

Platform Sponsor

Date for First Flight Goal Type Status

LEMV Army Late 

2011

3 deployable systems

Hybrid Under 

construction

BD2 Air Force Late 

2011

1 deployable system

Conventional Under 

construction

MZ-3A Navy 2006 1 operational 

system

Conventional Currently 

operating

DoD is currently fufield airships that wat low altitudes. Thare the Navy’s MZ-Devil Block II (BDEndurance Multi-I(LEMV). Conductaltitudes has the advvolume of buoyant weight. In additioncated sensors are usaltitudes for a given because those sensoand activities they aLow-altitude operadisadvantage of a smpossible from higheaircraft are easier foattack.The Navy’s MZ-3Aairship that entered currently operationannounced plans to seas, but it was used Deepwater Horizon Mexico, and today mental platform to determine how airsoperations. In its cuMZ-3A is the only that must carry a crrigid conventional length and has eighthe MZ-3A. The Afor the BD2 are to 2011 and to deploy operations overseas LEMV, a semirigid lar in volume to the to create an airfoil-flight and deploymsimilar to those for 
LOW-ALTITUDE INTELLIGENCE, SURVEILLANCE, AND RECONNAISSANCE RECENT DEVELOPM

CBO

Exhibit 5.

Payload, Endurance, and Speed of Low-Altitude Airships and 

Fixed-Wing Aircraft(Endurance, days)Source: Congressional Budget Office based on data provided by manufacturers.Notes: Solid circles denote airships, hatched circles denote fixed-wing aircraft. Circle area is proportional to 

payload.Performance characteristics are for typical mission profiles.

LEMV = Long-Endurance Multi-Intelligence Vehicle; BD2 = Blue Devil Block II. 

05

10152025

MQ-9 Reaper RQ-4 Global Hawk

BD2

LEMV

Orion

MQ-1

Predator

Grey Eagle

0 50 100 150 200 250 300 350 400

Speed (Knots)

Payload (Pounds)

2,500

500

The Air Force and into contracts to puairships for eventuaairships being built Air Force’s BD2 anBD2 is a nonrigid LEMV is a semirigThe BD2 is design20,000 feet with a five days. Its manufto deliver one BD2 The LEMV is desig20,000 feet with a 21 days. The first oto be delivered in tAfghanistan by earlThe planned endursubstantially greatefixed-wing unmannRQ-4 Global HawkPredator, all of whiday and a half or leconcept demonstrafive-day endurance The cruise speeds ogreater than those ofor the Global Hawcan both fly in excegives them the abilorbit location in reuation on the grouBecause many of thproduce a modern development, the cson to fixed-wing aand are not address
LOW-ALTITUDE INTELLIGENCE, SURVEILLANCE, AND RECONNAISSANCE RECENT DEVELOPM

CBO

Exhibit 6.

Payload-Duration of Low-Altitude Airships and Fixed-Wing Aircraft

(Payload-duration, pound-hours)Source: Congressional Budget Office based on data provided by manufacturers.Notes: The vertical axis uses a logarithmic scale.

Solid lines denote airships; dashed lines denote fixed-wing aircraft.

LEMV = Long-Endurance Multi-Intelligence Vehicle; BD2 = Blue Devil Block II.

0 250 500 750 1,000 1,250 1,500 1,750 2,000

100

1,000

10,000

100,000

1,000,000

10,000,000

Combat Radius (Nautical miles)

LEMV (Objective)

BD2 (Objective)

Orion (Objective)

Grey Eagle

MQ-9 Reaper

MQ-1 Predator

A summary measurpayload-duration is could be carried to amount of time it ction). Payload weigmeasure of the typean airship could capayload-duration fairships as a functiowhere the vehicle is located.If the BD2 and LEtives, they will provpayload-duration tclass unmanned airForce’s Predator anGrey Eagle. For examile combat radiushave a payload-durgreater than the Pre10 times greater thArmy’s LEMV wouabout 80 times thathermore, at comb500 nautical miles, the Predator, Reapemore rapidly than wof the airships becamost of the flight tPredator-class aircrThe objective perfoshow the same decrthe other conventioendurance it is beinmuch greater than toccurs beyond the Orion is, however, 
CBO

High-Altitude Intelligence, 

Surveillance, and Reconnaissance
HIGH-ALTITUDE INTELLIGENCE, SURVEILLANCE, AND RECONNAISSANCE RECENT DEVELOPM

CBO

Exhibit 7.

High-Altitude Airships for Intelligence, Surveillance, and 

ReconnaissanceSource: Congressional Budget Office based on data provided by manufacturers.Note: HALE-D = High-Altitude Long-Endurance Demonstrator; ASMDC = Army Space and Missile Defense 

Command; ISIS = Integrated Sensor Is the Structure; DARPA = Defense Advanced Research Projects 

Agency.

Platform Sponsor

Date for First Flight Goal Type Status

Traditional Designs

HALE-D Army/ASMDC July 2011 Scaled technology 

demonstrator

Conventional Prototype 

flown— suffered failure

HiSentinel Army/ASMDC November 

2010

Scaled technology demonstrator

Conventional Prototype 

flown— suffered failure

ISIS Demonstrator

DARPA 2013 Scaled technology 

demonstrator

Conventional Under 

construction

Designs with Detachable Return Vehicles

Star Light Navy Undetermined Technology 

demonstrator

Conventional with return payload

Under construction

High Altitude Shuttle System

Army 2009 Technology 

demonstrator

Conventional with return payload

Prototype flown

High-altitude ISR vstage of developmetems. Most current airships are of convthere have also been Design challenges finclude manufacturstrong enough for vdurable enough to atmosphere. Operanavigating through be greater than the Once at altitude, hhave the advantage could be threatened capable of reaching The Army’s High Agram includes the Haircraft and the Higance Demonstrator Army is also workinAdvanced Research on a subscale demoSensor Is the Structwould integrate a rture of the airship. High Altitude Shutairships are also tecthe demonstrators generation of vehiccapacities and enduBoth the HiSentinehowever, have suffeNovember 2010, thsion failure and lan24-hour mission. In a technical failure ahours into a plannerecovery operationswere destroyed, and by a fire. 


HIGH-ALTITUDE INTELLIGENCE, SURVEILLANCE, AND RECONNAISSANCE RECENT DEVELOPM

CBO

Exhibit 8.

Payload, Endurance, and Speed of High-Altitude Airships and 

Fixed-Wing Aircraft(Endurance, days)Source: Congressional Budget Office based on data provided by manufacturers.Notes: Solid circles denote airships; hatched circles denote fixed-wing aircraft. Circle area is proportional to 

payload.Performance characteristics are for typical mission profiles.

HAA = High Altitude Airship; HALE-D = High-Altitude Long-Endurance Demonstrator.

05

101520253035

MQ-9

Reaper

RQ-4

Global Hawk

Hi Sentinel

HALE-D

HAA-Objective

0 50 100 150 200 250 300 350 400

Speed (Knots)

HiSentinel

Long-Term Goal of HAA Program Payload (Pounds)

3,0001,000

The Army’s HAA pHiSentinel and HAstration aircraft, haof building an airsh2,000-pound paylowatts of power (to rsystems) at 65,000 The HiSentinel has capabilities but can load—80 lbs. The smaller payload and HiSentinel. The goHALE-D, howeverneeded for long ennot to demonstrate large payload.In comparison with craft, such as the Gairship meeting the HAA program wouand substantially loerably slower cruise 
HIGH-ALTITUDE INTELLIGENCE, SURVEILLANCE AND RECONNAISSANCE RECENT DEVELOPM

CBO

Exhibit 9.

Payload-Duration of High-Altitude Airships and Fixed-Wing Aircraft

(Payload-duration, pound hours)Source: Congressional Budget Office based on data provided by manufacturers.Notes: The vertical axis uses a logarithmic scale.

Solid lines denote airships; dashed lines denote fixed-wing aircraft. 

HAA = High Altitude Airship; HALE-D = High-Altitude Long-Endurance Demonstrator.

0 250 500 750 1,000 1,250 1,500 1,750 2,000

1,000

10,000

100,000

1,000,000

10,000,000

Combat Radius (Nautical miles)

Long-Term Goal

of HAA Program

HALE-D

RQ-4 Global Hawk

MQ-9 Reaper

HiSentinel

The fixed-wing Gloprominent high-altcraft in use today, acomparison point fAn airship meeting goals of the Army’s a payload-duration the Global Hawk’s the ability to carry useful from over 60altitudes, however, would need to be mtinel and HALE-D example, the relativISIS demonstrator Designs for unmanduration even greatobjective for the Hexplored. Two progairship and the Vulhave the goal of deremain continuousvehicle with that en1,000 pounds (the demonstration aircduration at least 30 HAA program’s ob
CBO

Airlift
AIRLIFT RECENT DEVELOPM

CBO

Exhibit 10.

Proposed Airships for Airlift

Source: Congressional Budget Office based on data provided by manufacturers.Note: DoD = Department of Defense; RRTO = Rapid Reaction Technology Office; LEMV = Long-Endurance 

Multi-Intelligence Vehicle.

Platform Sponsor

Date for First Flight Goal Type Status

Project Pelican

DoD RRTO 2012–2013 Scaled 

technology demonstrator

Hybrid Under 

construction

LEMVHeavy Privately funded Undetermined Proposed operational 

system

Hybrid Designs

proposed

SkyTug Privately 

funded

2012 Full-scale 

prototype

Hybrid Under 

construction

At least three cargo be fielded to providthe next few years abeen proposed. Thposed hybrid airshihull and use variabassist with controllwould be based on developed for ISR hybrid airship that P-791 technology din January 2006.CBO did not examother, much larger from 2003 to 2006Research Projects Acalled the Hybrid U(HULA), or Walruan airship able to cto 12,000 miles in a large aircraft is evbe a larger version such as the three deanalysis of how vermight perform relaconventional strategressional Budget O

Military Transporta

2005). 
AIRLIFT RECENT DEVELOPM

CBO

Exhibit 11.

Approximate Performance Characteristics of Proposed

Airships for AirliftSource: Congressional Budget Office based on data provided by manufacturers.Note: LEMV = Long-Endurance Multi-Intelligence Vehicle.

LEMV-Heavy SkyTug

Project Pelican

(Full-scale version)

Length 365 Feet 300 Feet 435 FeetFlight Altitude 9,000 Feet 10,000 Feet 10,000 FeetAverage Cruise Speed 80 Knots 80-100 Knots 90 KnotsMaximum Payload 50 Tons 20-30 Tons 60 Tons

Range 1,200 Miles 1,500 Miles 3,100 Miles

The LEMV-Heavyect Pelican airships about 20 tons to 60 1,000 to 3,000 naumance roughly spaperformance offeretransport aircraft sularger C-17 and C-much lower speeds would, but the airstage of greater indeHybrid airships wotoday’s transport herange and the abilitpayload.In addition to lift cairships’ cost and vand high winds woassess the suitability airlift missions. Altate at similar altitulower speeds than hmuch less maneuveavoid threats along stration of the needstage, and costs per and are not analyze
AIRLIFT RECENT DEVELOPM

CBO

Exhibit 12.

Airlift Performance for an Illustrative Deployment to the 

Middle EastSource: Congressional Budget Office.Note: LMSR = large, medium-speed roll-on/roll-off ship.

Aircraft Airships Sealift

C-17 60-Ton Airship 500-Ton Airship LMSR

Average Throughput Capacity per Single Aircraft or Ship (Million ton-miles/day)

0.25 0.12 1.0 9.5

Cargo Delivered per Single Aircraft or Ship (Tons)

By Day 5: 80 0 0 0

By Day 15: 230 110 900 0

By Day 30: 470 220 1,850 16,500

The terms “strategiare typically applied designed to move ccontinental distancproviders of strategC-17 aircraft and Ntary also has contraship operators to prtion services when used to characterize average throughput payload and the dismoved in a day. Detend to have the hiprimarily because tthan aircraft can. Ffrom the United Stsealift ship would pthroughput capacitever, could begin dsooner. When consby ship or aircraft, the need for a given allocate it to the limaircraft.Cargo airships coulcapability, deliverinships but not as quaircraft. The averagprovided by an airstional aircraft or shpayload. The proposhown earlier in thithroughput capacitpayloads would nopensate for their slowith payloads of 50proposed, and they throughput capacitairship with speed amatch a ship’s throuprobably be imprac
AIRLIFT RECENT DEVELOPM

CBO

Exhibit 13.

Illustration of the Number of Aircraft Needed to Provide 1,000 Tons 

per Day Throughput Within a Theater of Operations(Number of aircraft needed to maintain 1,000 tons/day)Source: Congressional Budget Office.Notes: Curves illustrate the approximate capabilities of selected aircraft using similar assumptions.

CH-47F = Chinook Helicopter; MV-22 = Osprey Tilt-Rotor Aircraft; LEMV= Long-Endurance MultiIntelligence Vehicle.

0 50 100 150 200 250 300 350 400 450 500

0

20406080

100

Distance to Delivery (Nautical miles)

MV-22

CH-47F

LEMV-Heavy

Project Pelican

SkyTug

The terms “tactical are applied to systemove cargo or peoptions—typically a fTactical lift can be wing aircraft for airand vertical takeoff copters or the tilt-rtransport to locatioairbases.Cargo airships with have the potential tthat would currentlMV-22. Although contemporary helic90 knots versus mocopters—the LEMthe Project Pelican payloads and longesiderably faster than “airplane mode,” wpropellers on a fixespeed of more than limited to carrying the substantial capacarried suspended b“helicopter mode.”At distances up to athe number of airshgiven cargo throughtons per day) would of today’s vertical taAt distances longer greater ranges offerwould enable them throughput with fewould allow a singlseveral forward outpthe several individuneeded with today’s