The Space Shuttle and Its Operations 53

The Space

Shuttle and

Its Operations

The Space Shuttle

Processing the

Shuttle for Flight

Flight Operations

Extravehicular Activity

Operations and Advancements

Shuttle Builds the

International Space Station
The Space Shuttle design was remarkable. The idea of “wings in orbit”

took concrete shape in the brilliant minds of NASA engineers, and

the result was the most innovative, elegant, versatile, and highly

functional vehicle of its time. The shuttle was indeed an engineering

marvel on many counts. Accomplishing these feats required the design

of a very complex system.

In several ways, the shuttle combined unique attributes not witnessed

in spacecraft of an earlier era. The shuttle was capable of launching

like a rocket, reentering Earth’s atmosphere like a capsule, and

flying like a glider for a runway landing. It could rendezvous and

dock precisely, and serve as a platform for scientific research within

a range of disciplines that included biotechnology and radar

mapping. The shuttle also performed satellite launches and repairs,

bestowing an almost “perpetual youth” upon the Hubble Space

Telescope through refurbishments.

The most impressive product that resulted from the shuttle’s capabilities

and contributions is the International Space Station—a massive

engineering assembly and construction undertaking in space.

No other crewed spacecraft to date has replicated these capabilities.

The shuttle has left an indelible mark on our society and culture,

and will remain an icon of space exploration for decades to come.

54 The Space Shuttle and Its Operations

The Space

Shuttle

Roberto Galvez

Stephen Gaylor

Charles Young

Nancy Patrick

Dexer Johnson

Jose Ruiz
What Was the

Space Shuttle?

Physical Characteristics

The Space Shuttle was the most

complex space vehicle design of its

time. It was comprised of four main

components: the External Tank (ET);

three Space Shuttle Main Engines;

two Solid Rocket Boosters (SRBs);

and the Orbiter vehicle. It was the

first side-mounted space system

dictated by the need to have a large

winged vehicle for cross-range

capability for re-entry into Earth’s

atmosphere and the ability to land a

heavyweight payload.

These four components provided the

shuttle with the ability to accomplish

a diverse set of missions over its

flight history. The Orbiter’s heavy

cargo/payload carrying capability, along

with the crew habitability and

flexibility to operate in space, made

this vehicle unique. Because of its lift

capability and due-East inclination, the

shuttle was able to launch a multitude

of satellites, Spacelab modules, science

platforms, interplanetary probes,

Department of Defense payloads, and

components/modules for the assembly

of the International Space Station (ISS).

The shuttle lift capability or payload

decreased with increased operational

altitude or orbit inclination because

more fuel was required to reach the

higher altitude or inclination.

Shuttle lift capability was also limited

by total vehicle landing weight—

different limits for different cases

(nominal or abort landing). An abort

landing was required if a system failure

The Space Shuttle and Its Operations 55

Orbiter

Space Shuttle Main Engine

External Tank

Solid Rocket Booster

External Tank

Space Shuttle Main Engine So er

Space Shuttle Launch Configuration
during ascent caused the shuttle not to

have enough energy to reach orbit or

was a hazard to crew or mission. Abort

landing sites were located around the

world, with the prime abort landing sites

being Kennedy Space Center (KSC) in

Florida, Dryden Flight Research Center

on the Edwards Air Force Base in

California, and Europe.

The entire shuttle vehicle, fully

loaded, weighed about 2 million kg

(4.4 million pounds) and required a

combined thrust of about 35 million

newtons (7.8 million pounds-force)

to reach orbital altitude. Thrust was

provided by the boosters for the first

2 minutes and the main engines for

the approximately 8 minutes and

30 seconds ascent required for the

vehicle to reach orbital speed at the

requisite altitude range of 185 to about

590 km (100 to 320 nautical miles).

Once in orbit, the Orbital Maneuvering

System engines and Reaction Control

System thrusters were used to perform

all orbital operations, Orbiter

maneuvers, and deorbit. Re-entry

required orbital velocity decelerations

of about 330 km/hr (204 mph)

depending on orbital altitude, which

caused the Orbiter to slow and fall

back to Earth.

The Orbiter Thermal Protection System,

which covered the entire vehicle,

provided the protection needed to

survive the extreme high temperatures

experienced during re-entry. Primarily

friction between the Orbiter and the

Earth’s atmosphere generated

temperatures ranging from 927°C

(1,700°F) to 1,600°C (3,000°F). The

highest temperatures experienced were

on the wing leading edge and nose cone.

The time it took the Orbiter to start

its descent from orbital velocity of

about 28,160 km/hr (17,500 mph) to

a landing speed of about 346 km/hr

(215 mph) was 1 hour and 5 minutes.

During re-entry, the Orbiter was

essentially a glider. It did not have

any propulsion capability, except for

the Reaction Control System thrusters

required for roll control to adjust its

trajectory early during re-entry.

Management of the Orbiter energy

from its orbital speed was critical

to allow the Orbiter to reach its

desired runway target. The Orbiter’s

limited cross-range capability of about

1,480 km (800 nautical miles) made

management of the energy during

final phases of re-entry close to the

ground—otherwise called terminal

area energy management—critical

for a safe landing.

The Orbiter performed as a glider

during re-entry, thus its mass properties

had to be well understood to ensure that

the Flight Control System could control

the vehicle and reach the required

landing site with the right amount of

energy for landing. One of the critical

components of its aerodynamic flight

was to ensure that the Orbiter center of

gravity was correctly calculated and

entered into the Orbiter flight design

process. Because of the tight center of

gravity constraints, the cargo bay

payloads were placed in the necessary

cargo bay location to protect the down

weight and center of gravity of the

Orbiter for landing. Considering the

Orbiter’s size, the center of gravity box

was only 91 cm (36 in.) long, 5 cm

(2 in.) wide, and 5 cm (2 in.) high.

External Tank

The ET was 46.8 m (153.6 ft) in length

with a diameter of 8.4 m (27.6 ft),

which made it the largest component

of the shuttle. The ET contained two

internal tanks—one for the storage of

liquid hydrogen and the other for the

storage of liquid oxygen. The hydrogen

tank, which was the bigger of the two

internal tanks, held 102,737 kg

(226,497 pounds) of hydrogen. The

oxygen tank, located at the top of the

ET, held 619,160 kg (1,365,010 pounds)

of oxygen. Both tanks provided the fuel

to the main engines required to provide

the thrust for the vehicle to achieve a

safe orbit. During powered flight and

ascent to orbit, the ET provided about

180,000 L/min (47,000 gal/min) of

hydrogen and about 67,000 L/min

(18,000 gal/min) of oxygen to all three

Space Shuttle Main Engines with a

6-to-1 mixture ratio of liquid hydrogen

to liquid oxygen.

Solid Rocket Boosters

The two SRBs provided the main

thrust to lift the shuttle off the launch

pad. Each booster provided about

14.7 meganewtons (3,300,000

pounds-force) of thrust at launch, and

they were only ignited once the three

main engines reached the required

104.5% thrust level for launch.

Once the SRBs were ignited, they

provided about 72% of the thrust

required of the entire shuttle at liftoff

and through the first stage, which

ended at SRB separation.

The SRB thrust vector control system

enabled the nozzles to rotate, allowing

the entire shuttle to maneuver to the

required ascent trajectory during

first stage. Two minutes after launch,

the spent SRBs were jettisoned,

having taken the vehicle to an altitude

of about 45 km (28 miles). Not only

were the boosters reusable, they were

also the largest solid propellant motors

in use then. Each measured about

45.4 m (149 ft) long and about 3.6 m

(12 ft) in diameter.

56 The Space Shuttle and Its Operations
The Space Shuttle and Its Operations 57

Liquid Oxygen Feedline

Liquid Hydrogen Tank

Repressurization Line

Internal Stringers

Solid Rocket Booster 

Forward Attachment

Anti-slosh

Bafes

Liquid Hydrogen Tank

Inter Tank

Gaseous Oxygen

Vent Valve and

Fairing

Anti-vortex

Bafes

Liquid Oxygen Tank

Repressurization Line

Liquid Oxygen Tank

Nose Cap

(pilot and

drogue

parachutes)

Three Main 

Parachutes

Avionics

Systems Tunnel

Case Stiffener Rings

Thrust Vector Actuators

Aft Booster

Separation

Motor

Aft Skirt

Aft Exit Cone

Forward Booster Separation Motors

Frustum

Forward Skirt

Igniter/Safe and Arm

Forward Segment With Igniter

Forward-Center Segment

Avionics

Aft Segment

With Nozzle

Three Aft Attach Struts 

(External Tank attach ring)

Aft-Center Segment

External Tank

Solid Rocket Boosters
Space Shuttle Main Engines

After SRB separation, the main engines

provided the majority of thrust required

for the shuttle to reach orbital velocity.

Each main engine weighed about

3,200 kg (7,000 pounds). With a total

length of 4.3 m (14 ft), each engine,

operating at the 104.5% power level,

provided a thrust level of about 1.75

meganewtons (394,000 pounds-force)

at sea level and about 2.2 meganewtons

(492,000 pounds-force) at vacuum

throughout the entire 8 minutes and

30 seconds of powered flight. The

engine nozzle by itself was 2.9 m

(9.4 ft) long with a nozzle exit diameter

of 2.4 m (7.8 ft). Due to the high heat

generated by the engine thrust, each

engine contained 1,082 tubes throughout

its entire diameter, allowing circulation

of liquid hydrogen to cool the nozzle

during powered flight. The main

engines were a complex piece of

machinery comprised of high- and

low-pressure fuel and oxidizer pumps,

engine controllers, valves, etc. The

engines were under constant control

by the main engine controllers. These

consisted of an electronics package

mounted on each engine to control

engine operation under strict and critical

performance parameters. The engines

ran at 104.5% performance for much

of the entire operation, except when

they were throttled down to about

58 The Space Shuttle and Its Operations

Low-pressure

Oxidizer

Turbopump High-pressure

Oxidizer

Turbopump

Low-pressure

Fuel Turbopump

Controller

Nozzle

Main 

Injector

High-pressure

Fuel Turbopump

Main

Combustion

Chamber

Space Shuttle Main Engine
72% during first stage to preclude

having the vehicle exceed structural

limits during high dynamic pressure as

well as close to main engine shutdown

to preclude the vehicle from exceeding

3 gravitational force (3g) limits.

The only manual main engine control

capability available to the crew was

the manual throttle control, which

allowed the crew to decrease engine

performance from 104.5% to a level

of 72% if required for vehicle control.

The main engines had the capability

to gimbal about 10.5 degrees up and

down and 8.5 degrees to either side to

change the thrust direction required

for changes in trajectory parameters.

Orbiter

The Orbiter was the primary component

of the shuttle; it carried the crew

members and mission cargo/payload

hardware to orbit. The Orbiter was about

37.1 m (122 ft) long with a wingspan of

about 23.8 m (78 ft). The cargo/payload

carrying capacity was limited by the

18.3-m- (60-ft)-long by 4.6-m- (15-ft)-

wide payload bay. The cargo/payload

weighed up to 29,000 kg (65,000

pounds), depending on the desired

orbital inclination. The Orbiter payload

bay doors, which were constructed of

graphite epoxy composite material, were

18.3 m (60 ft) in length and 4.5 m (15 ft)

in diameter and rotated through an angle

of 175 degrees. A set of radiator panels,

affixed to each door, dissipated heat

from the crew cabin avionic systems.

The first vehicle, Columbia, was the

heaviest Orbiter fabricated due to

the installation of additional test

instrumentation required to gather data

on vehicle performance. As each Orbiter

was fabricated, the test instrumentation

was deleted and system changes

implemented, resulting in each

subsequent vehicle being built lighter.

The Orbiter crew cabin consisted of

the flight deck and the middeck and

could be configured for a maximum

crew size of seven astronauts,

including their required equipment

to accomplish the mission objectives.

The flight deck contained the Orbiter

cockpit and aft station where all the

vehicle and systems controls were

located. The crew used six windows in

the forward cockpit, two windows

overhead, and two windows looking

aft for orbit operations and viewing.

The middeck was mostly the crew

accommodations area, and it housed

all the crew equipment required to

live and work in space. The middeck

also contained the three avionic bays

where the Orbiter electronic boxes

were installed. Due to their limited

power generation capability, the

Orbiter fuel cells consumables (power

generation cryogenics) provided

mission duration capability on the

order of about 12 to 14 days, dependent

on vehicle configuration.

In 2006, NASA put into place the

Station-to-Shuttle Power Transfer

System, which allowed the ISS to

provide power to the Orbiter vehicle,

thereby allowing the Orbiter to

have a total mission duration of

about 16 days. The Orbiter

configuration (amount of propellant

loaded in the forward and aft

propellant tanks, payload mounting

hardware in the payload bay, loading

of cryogenic tanks required for power

generation, crew size, etc.) was

adjusted and optimized throughout

the pre-mission process.

Because of its payload size and

robotic arm capability, the Orbiter

could be configured to perform as a

platform for different cargo/payload

hardware configurations. In the total

132 Space Shuttle missions (as of

October 2010) over a period of 29 years,

The Space Shuttle and Its Operations 59

James Thompson, Jr.

Space Shuttle Main Engine project

manager (1974-1982).

Deputy NASA administrator (1989-1991).

“A major problem we had to solve

for the Space Shuttle Main Engine

was called rotary stability subsynchronous whorl. After numerous theories and

suggestions on turbo machinery, Joe Stangler at Rocketdyne and his team came

up with the vortex and vaporizing theory down in the passages. He proposed

putting a paddle in the flow stream and killing the vortex. Even though I thought

Joe’s theory was crazy, 2 weeks before the program review they had success.

Government, industries, and universities all contributed to its success.”
the Orbiter deployed a multitude of

satellites for Earth observation and

telecommunications; interplanetary

probes such as Galileo/Jupiter

spacecraft and Magellan/Venus Radar

Mapper; and great observatories that

included the Hubble Space Telescope,

Compton Gamma Ray Observatory,

and Chandra X-ray Observatory. The

Orbiter even functioned as a science

platform/laboratory; e.g., Spacelab,

Astronomy Ultraviolet Telescope,

US Microgravity Laboratory, US

Microgravity Payload, etc. Aside from

the experiments and satellite

deployments the shuttle performed,

its most important accomplishment was

the delivery and assembly of the ISS.

Space Shuttle Reusability

All components of the Space Shuttle

vehicle, except for the ET, were

designed to be reusable flight after

flight. The ET, once jettisoned from the

Orbiter, fell to Earth where atmospheric

heating caused the tank to break up

over the ocean.

The SRBs, once jettisoned from the

tank, parachuted back to the ocean

where they were recovered by special

ships and brought back to KSC.

With their solid propellant spent, the

boosters were de-stacked and shipped

back to aerospace and defense

company Thiokol in Utah for

refurbishment and reuse. The SRBs

were thoroughly inspected after every

mission to ensure that the components

were not damaged and could be

refurbished for another flight. Any

damage found was either repaired or

the component was discarded.

The Orbiter was the only fully

reusable component of the shuttle

system. Each Orbiter was designed

and certified for 100 space missions

and required about 5 months, once

it landed, to service the different

systems and configure the payload

bay to support requirements for

its next mission. NASA replaced

the components only when they

sustained a system failure and

could not be repaired. Even

though certified for 100 missions,

Discovery, Atlantis, and Endeavour

completed 39, 32, and 25 missions,

respectively, by October 2010.

Challenger flew 10 missions and

Columbia flew 28 missions before

their loss on January 28, 1986, and

February 1, 2003, respectively.

60 The Space Shuttle and Its Operations

Monomethylhydrazine and 

Nitrogen Tetroxide Tanks

Rudder and

Speed Brake

Main Engines 

(3 total)

Maneuvering 

Engines 

(2 total)

Aft Control

Thrusters

Body Flap

Elevon

The Orbiter
The Space Shuttle and Its Operations 61

Space Radiators

(inside doors)

Main Landing Gear

Manipulator Arm

Flight Deck

Electrical System

Fuel Cells

Middeck

Nose Gear

Forward

Control 

Thrusters

Payload: Long-duration Exposure Facility

Liftoff from Kennedy

Space Center, Florida

Solid Rocket 

Booster Separation

Mission Time 

approx. 0:02:02

Elevation 50 km

(163,000 ft)

Solid Rocket Booster Landing

Mission Time approx. 0:07:13

External Tank Impact

Indian Ocean

Main Engine Cutoff

Mission Time approx. 0:08:32

Elevation 117 km (383,000 ft)

Nominal Orbit about 278 km

(150 nautical miles)

T

Entry Interface

Elevation 122 km

(400,000 ft)

About 7,963 km

(4,300 nautical miles)

from Landing Site

Landing 

Speed 364 kph

(196 knots or 226 mph)

External Tank Separation

Mission Time approx. 0:08:50

Orbital Maneuvering System

Orbital Insertion

On-orbit

Operations

Orbital Maneuvering 

System Deorbit Burn

00:00:00 = Hours:Minutes:Seconds

Typical Flight Profile
Automation, Autonomy,

and Redundancy

The Space Shuttle was the first space

vehicle to use the fly-by-wire

computerized digital flight control

system. Except for manual switch

throws for system power-up and certain

valve actuations, control of the Orbiter

systems was through the general

purpose computers installed in the

forward avionics bay in the middeck.

Each Orbiter had five hardwareidentical general purpose computers;

four functioned as the primary means to

control the Orbiter systems, and one

was used as a backup should a software

anomaly or problem cause the loss of

the four primary computers. During

ascent and re-entry—the critical phases

of flight—four general purpose

computers were used to control the

spacecraft. The primary software, called

the Primary Avionics Software System,

was divided into two major systems:

system software, responsible for

computer operation, synchronization,

and management of input and output

operations; and applications software,

which performed the actual duties

required to fly the vehicle and operate

the vehicle systems.

Even though simple in their architecture

compared to today’s computers, the

general purpose computers had a

complex redundancy management

scheme in which all four primary

computers were tightly coupled together

and processed the same information

at the same time. This tight coupling

was achieved through synchronization

steps and cross-check results of their

processes about 440 times per second.

The original International Business

Machines computers had only about

424 kilobytes of memory each. The

central processing unit could process

about 400,000 instructions per second

and did not have a hard disk drive

capability. These computers were

replaced in April 1991 (first flight was

STS-37) with an upgraded model that

had about 2.5 times the memory capacity

and three times the processor speed.

To protect against corrupt software, the

general purpose computers had a

backup computer that operated with a

completely different code independent

of the Primary Avionics Software

System. This fifth computer, called the

Backup Flight System, operated in the

background, processing the same

critical ascent/re-entry functions in case

the four general purpose computers

failed or were corrupted by problems

with their software. The Backup Flight

System could be engaged at any

moment only by manual crew

command, and it also performed

oversight and management of Orbiter

noncritical functions. For the first 132

flights of the Space Shuttle Program,

the Backup Flight System computer

was never engaged and, therefore, was

not used for Orbiter control.

The overall avionics system architecture

that used the general purpose

computer redundancy was developed

with a redundancy requirement for

fail-operational/fail-safe capability.

These redundancy schemes allowed for

the loss of redundancy in the avionics

systems and still allowed continuation

of the mission or safe landing of the

Orbiter. All re-entry critical avionics

functions, such as general purpose

computers, aero surface actuators, rate

gyro assemblies, accelerometer

assemblies, air data transducer

assemblies, etc., were designed with

four levels of redundancy. This meant

that each of these functions was

controlled by four avionic boxes that

performed the same specific function.

The loss of the first box allowed for

safe continuation of the mission.

The loss of the second box still allowed

the function to work properly with

only two remaining boxes, which

subsequently allowed for safe re-entry

and landing of the Orbiter. Other

critical functions were designed with

only triple redundancy, which meant

that fail-operational/fail-safe reliability

allowed the loss of two of the boxes

before the function was lost.

The avionics systems redundancy

management scheme was essentially

controlled via computer software that

operated within the general purpose

computers. This scheme was to select

the middle value of the avionics

components when the systems had

three or four avionics boxes executing

the same function. On loss of the first

box, the redundancy management

scheme would down mode to the

“average value” of the input received

from the functioning boxes. Upon the

second box failure, the scheme would

further down mode to the “use value,”

which essentially meant that the

function was performed by using input

data from only one remaining unit in

the system. This robust avionics

architecture allowed the loss of

avionics redundancy within a function

without impacting the ability of the

Orbiter to perform its required mission.

Maneuverability, Rendezvous,

and Docking Capability

Maneuverability

The Orbiter was very maneuverable and

could be tightly controlled in its pointing

accuracy, depending on the objective it

was trying to achieve. The Orbiter

controllability and pointing capability

was performed by the use of 44 Reaction

Control System thrusters installed both

in the forward and the aft portions of the

62 The Space Shuttle and Its Operations
vehicle. Of the 44 thrusters, six were

Reaction Control Systems and each

had a thrust level of only 111 newtons

(25 pounds-force). The remaining

38 thrusters were considered primary

thrusters and each had a thrust level of

3,825 newtons(860 pounds-force).

The total thruster complement was

divided between the forward thrusters

located forward of the crew cabin, and

the aft thrusters located on the two

Orbital Maneuvering System pods in

the tail of the Orbiter. The forward

thrusters (total of 16) consisted of

14 primary thrusters and two vernier

thrusters. Of the 28 thrusters in the aft,

24 were primary thrusters and four

were vernier thrusters. The thrusters

were installed on the Orbiter in such a

way that both the rotational and the

translational control was provided to

each of the Orbiter’s six axes of control

with each axis having either two or

three thrusters available for control.

The Orbital Maneuvering System

provided propulsion for the shuttle.

During the orbit phase of the flight, it

was used for the orbital maneuvers

needed to achieve orbit after the Main

Propulsion System had shut down.

It was also the primary propulsion

system for orbital transfer maneuvers

and the deorbit maneuver.

The general purpose computers also

controlled the tight Orbiter attitude

and pointing capability via the Orbiter

Digital Auto Pilot—a key piece of

application software within the

computers. During orbit operations,

the Digital Auto Pilot was the primary

means for the crew to control Orbiter

pointing by the selection of different

attitude and attitude rate deadbands,

which varied between +/-1.0 and

5.0 degrees for attitude and +/-0.02 and

0.2 deg/sec for attitude rate. The Digital

Auto Pilot could perform three-axis

automatic maneuver, attitude tracking,

and rotation about any axis or body

vector. Crew interface to the Digital

The Space Shuttle and Its Operations 63

Forward Reaction

Control System

(16 jets)

Jets

Reaction Control 

System Jets

Reaction 

Control 

System 

Jets

Reaction Control 

System Jets

Jets

Right Aft Propulsion 

System Pod

(14 jets, 1 Orbital

Maneuvering 

System engine)

Left Aft Propulsion 

System Pod

(14 jets, 1 Orbital

Maneuvering

System engine)

Orbital 

Maneuvering 

System Engines

Orbital 

Maneuvering 

System 

Engine

Reaction Control Thrusters and Orbital Maneuvering System
Auto Pilot was via the Orbiter cathode

ray tubes/keyboard interface, which

allowed the crew to control parameters

in the software. With very accurate

control of its orientation, the Orbiter

could provide a pointing capability to

any part of the celestial sky as required

to accomplish its mission objectives.

Rendezvous and Docking

The shuttle docked to, grappled,

deployed, retrieved, and otherwise

serviced a more diverse set of orbiting

objects than any other spacecraft in

history. It became the world’s first

general purpose space rendezvous

vehicle. Astronauts retrieved payloads

no larger than a refrigerator and docked

to targets as massive as the ISS, despite

the shuttle being designed without

specific rendezvous targets in mind.

In fact, the shuttle wasn’t designed

to physically dock with anything; it

was intended to reach out and grapple

objects with its robotic arm.

A rendezvous period lasted up to 4 days

and could be divided into three phases:

ground targeted; on-board targeted; and

human-piloted proximity operations.

The first phase began with launch into a

lower orbit, which lagged the target

vehicle. The Orbiter phased toward the

target vehicle due to the different

orbital rates caused by orbital altitude.

Mission Control at Johnson Space

Center tracked the shuttle via ground

assets and computed orbital burn

parameters to push the shuttle higher

toward the target vehicle. As the shuttle

neared the target, it transitioned to

on-board targeting using radar and star

trackers. These sensors provided

navigation data that allowed on-board

computers to calculate subsequent

orbital burns to reach the target vehicle.

The final stage of rendezvous

operations—proximity operations—

began with the Orbiter’s arrival within

thousands of meters (feet) of the target

orbital position. During proximity

operations, the crew used their highest

fidelity sensors (laser, radar, or direct

measurement out the window with a

camera) to obtain the target vehicle’s

relative position. The crew then

transitioned to manual control and

used the translational hand controller

to delicately guide the Orbiter in for

docking or grappling operations.

The first rendezvous missions targeted

satellite objects less massive than the

shuttle and grappled these objects with

its robotic arm. During the proximity

operations phase, the commander only

had a docking camera view and

accompanying radar information to

guide the vehicle. Other astronauts

aimed payload bay cameras at the target

and recorded elevation angles, which

were charted on paper to give the

commander awareness of the Orbiter’s

position relative to the target. Once the

commander maneuvered into a position

where the target was above the payload

bay, a mission specialist grappled the

target with the robotic arm. This method

proved highly reliable and applicable to

a wide array of rendezvous missions.

Shuttle rendezvous needed a new

strategy to physically dock with large

vehicles: the Russian space station Mir

and the ISS. Rendezvous with larger

space stations required more precise

navigation, stricter thruster plume

limitations, and tighter tolerances

during docking operations. New tools

such as the laser sensors provided

highly accurate range and range rate

information for the crew. The laser was

mounted in the payload bay and its

data were routed into the shuttle cabin

but could not be incorporated directly

into the shuttle guidance, navigation,

and control software. Instead, data

were displayed on and controlled by

a laptop computer mounted in the aft

cockpit. This laptop hosted software

called the Rendezvous Proximity

Operations Program that displayed

the Orbiter’s position relative to the

target for increased crew situational

awareness. This display was used

extensively by the commander to

manually fly the vehicle from 610 m

(2,000 ft) to docking.

This assembly of hardware and

software aptly met the increased

accuracy required by delicate docking

mechanisms and enabled crews to pilot

the massive shuttle within amazing

tolerances. In fact, during the final

0.9 m (3 ft) of docking with the ISS,

the Orbiter had to maintain a 7.62-cm

(3-in.) lateral alignment cylinder and

the closing rate had to be controlled

to within 0.02 m/sec (0.06 ft/sec).

The commander could control this

with incredibly discrete pulses of the

Reaction Control System thrusters.

Both the commander and the pilot

were trained extensively in the art of

shuttle proximity operations, learning

techniques that allowed them to

pilot the Orbiter to meet tolerances.

The shuttle was never meant to be

piloted to this degree of accuracy, but

innovative engineering and training

made these dockings uneventful and

even routine.

The success of shuttle rendezvous

missions was remarkable considering

its operational complexity. Spacecraft

rendezvous is an art requiring the

highly scripted choreography of

hardware systems, astronauts, and

members of Mission Control. It is a

precise and graceful waltz of billions

of dollars of hardware and human

decision making.

64 The Space Shuttle and Its Operations
Robotic Arm/Operational

Capability

The Canadian Space Agency provided

the Shuttle Robotic Arm. It was

designed, built, and tested by Spar

Aerospace Ltd., a Canadian Company.

The electromechanical arm measured

about 15 m (50 ft) long and 0.4 m

(15 in.) in diameter with a six-degreeof-freedom rotational capability, and

it consisted of a manipulator arm that

was under the control of the crew via

displays and control panels located in

the Orbiter aft flight deck. The Shuttle

Robotic Arm was comprised of six

joints that corresponded roughly to

the joints of a human arm and could

handle a payload weighing up to

29,000 kg (65,000 pounds). An end

effector was used to grapple a

payload or any other fixture and/or

component that had a grapple fixture

for handling by the arm.

The Space Shuttle and Its Operations 65

The Orbiter Boom

Sensor System inspects

the wing leading edge.

This system was built

for inspections after

the Columbia accident

(STS-107 [2003]).

STS-88 (1998)

Endeavour’s Shuttle

Robotic Arm grapples the

Russian Module Zarya

for berthing onto the

International Space Station

(ISS) Node 1, thus

beginning the assembly

sequence for the ISS.

Area of Inspection

Sensor

Boom

Post-Columbia-Accident Inspection System
Even though NASA used the Shuttle

Robotic Arm primarily for handling

payloads, it could also be used as a

platform for extravehicular activity

(EVA) crew members to attach

themselves via a portable foot restraint.

The EVA crew member, affixed to the

portable foot restraint grappled by the

end effector, could then be maneuvered

around the Orbiter vehicle as required

to accomplish mission objectives.

Following the Return to Flight after the

loss of Columbia, the Shuttle Robotic

Arm was used to move around the

Orbiter Boom Sensor System, which

allowed the flight crew to inspect the

Thermal Protection System around

the entire Orbiter or the reinforced

carbon-carbon panels installed on the

leading edge of the wings.

During buildup of the ISS, the Shuttle

Robotic Arm was instrumental in the

handling of modules carried by the

Orbiter—a task that would not have

been possible without the use of this

robotic capability.

Extravehicular Activity

Capability

The Space Shuttle Program provided

a dramatic expansion in EVA

capability for NASA, including the

ability to perform tasks in the space

environment and ways to best protect

and accommodate a crew member

in that environment. The sheer

number of EVAs performed during

the course of the program resulted

in a significant increase in knowledge

of how EVA systems and EVA crew

members perform.

Prior to the start of the program, a total

of 38 EVAs were performed by all US

space programs combined, including

Gemini, Apollo, and Skylab. During

previous programs, EVAs focused

primarily on simple tasks, such as the

jettison of expended hardware or

the collection of geology samples.

The Space Shuttle Program advanced

EVA capability to construction of

massive space structures, high-strength

maneuvers, and repair of complicated

engineering components requiring a

combination of precision and gentle

handling of sensitive materials and

structures. As of October 2010, the

shuttle accomplished about 157 EVAs

in 132 flights. Of those EVAs,

105 were dedicated to ISS assembly

and repair tasks. Shuttle EVA

crews succeeded in handling and

manipulating elements as large as

9,000 kg (20,000 pounds); relocating

and installing large replacement

parts; capturing and repairing failed

satellites; and performing surgical-like

repairs of delicate solar arrays, rotating

joints, and much more.

The Orbiter’s EVA capability consisted

of several key engineering components

and equipment. For a crew member to

step out of the shuttle and safely enter

the harsh environment of space, that

crew member had to use the integrated

airlock, an extravehicular mobility unit

spacesuit, a variety of EVA tools, and

EVA translation and attachment aids

attached to the vehicle or payload. EVA

tools consisted of a suite of components

that assisted in handling and translating

cargo, translating and stabilizing at

the work site, operating manual

mechanisms, and attaching bolts and

fasteners, often with relatively precise

torque requirements. Photo and

television operations provided

documentation of the results for future

troubleshooting, when necessary.

Extravehicular Mobility Unit

The extravehicular mobility unit

was a fully self-sufficient individual

spacecraft providing critical life

support systems and protection from

the harsh space environment. Unlike

previous suits, the shuttle suit was

designed specifically for EVA and was

the cornerstone component for safe

conduct of EVA during the shuttle era.

It operated at 0.03 kgf/cm2 (4.3 psi)

pressure in the vacuum environment

and provided thermal protection for

interfacing with environments and

components from -73°C (-100°F) to

177°C (350°F). It provided oxygen

and removed carbon dioxide during

an EVA, and it supplied battery power

to run critical life support and ancillary

extravehicular mobility unit systems,

including support lights, cameras,

and radio. The suit, which also

provided crew members with critical

feedback on system operations

during EVA, was the first spacesuit

controlled by a computer.

Future space programs will benefit

tremendously from NASA’s EVA

experience during the shuttle flights.

To ensure success, the goal has

been and always will be to design

for EVAs that are as simple and

straightforward as possible. Fewer

and less-complicated provisions will

be required for EVA interfaces on

spacecraft, and functions previously

thought to require complicated and

automated systems can now rely on

EVA instead. During the shuttle era,

NASA took the training wheels off

of EVA capability and now has a

fully developed and highly efficient

operational resource in support of

both scheduled and contingency

EVA tasks.

66 The Space Shuttle and Its Operations
Flight Deck

Crew Compartment

Accommodation for Crew

and Payloads

The Orbiter’s crew cabin had a

habitable volume of 71.5 m3 (2,525 ft3)

and consisted of three levels: flight

deck, middeck, and utility area.

The flight deck, located on the top

level, accommodated the commander,

pilot, and two mission specialists

behind them. The Orbiter was

flown and controlled from the

flight deck. The middeck, located

directly below the flight deck,

accommodated up to three additional

crew members and included a

galley, toilet, sleep locations, storage

lockers, and the side hatch for

entering and exiting the vehicle.

The Orbiter airlock was also located

The Space Shuttle and Its Operations 67

Flight deck showing the commander and pilot seats, along with cockpit controls.
Middeck

Crew compartment middeck configuration showing the forward middeck lockers in Avionics Bay 1 and 2, crew seats, and sleeping bags.

in the middeck area; it allowed

up to three astronauts, wearing

extravehicular mobility unit

spacesuits, to perform an EVA in

the vacuum of space. The standard

practice was for only two crew

members to perform an EVA.

Most of the day-to-day mission

operations took place on the middeck.

The majority of hardware required

for crew members to live, work, and

perform their mission objectives was

stowed in stowage lockers and bags

within the middeck volume. The entire

middeck stowage capability was

equivalent to 127.5 middeck lockers in

which each locker was about 0.06 m3

(2 ft3) in volume. This volume could

accommodate all required equipment

and supplies for a crew of seven for as

many as 16 days.

68 The Space Shuttle and Its Operations
Performance Capabilities

and Limitations

Throughout the history of the

program, the versatile shuttle vehicle

was configured and modified to

accomplish a variety of missions,

including: the deployment of Earth

observation and communication

satellites, interplanetary probes, and

scientific observatories; satellite

retrieval and repair; assembly; crew

rotation; science and logistics resupply

of both the Russian space station Mir

and the ISS, and scientific research

and operations. Each mission type had

its own capabilities and limitations.

Deploying and Servicing Satellites

The largest deployable payload

launched by the shuttle in the life of

the program was the Chandra X-ray

Observatory. Deployed in 1999 at an

inclination of 28.45 degrees and an

altitude of about 241 km (130 nautical

miles), Chandra—and the support

equipment deployed with it—weighed

22,800 kg (50,000 pounds).

In 1990, NASA deployed the

Hubble Space Telescope into a

28.45-degree inclination and a 555-km

(300-nautical-mile) altitude. Hubble

weighed 13,600 kg (30,000 pounds).

Five servicing missions were conducted

over the next 19 years to upgrade

Hubble’s science instrumentation,

thereby enhancing its scientific

capabilities. These subsequent

servicing missions were essential in

The Space Shuttle and Its Operations 69

Payload Weight

The Orbiter’s Altitude 

Endeavour

Atlantis

Discovery

50

48

46

44

42

40

22

20

18

Pounds

(x1,000)

Kilograms

(x1,000)

150160170180190200210220230240250260270280

Deploy scenarios are

downweight limited

below 388 kilometers 

(210 nautical miles)

Nautical 

Miles

278333388444500

Kilometers

Maximum Deploy Capability for Each Vehicle Versus Altitude

The up-mass

capability

of the shuttle

decreased

relative to the

orbital altitude.

Atlantis’ (STS-125 [2009]) robotic arm

lifts Hubble from the cargo bay and is

moments away from releasing the orbital

observatory to start it on its way back

home to observe the universe.
correcting the Hubble mirror spherical

aberration, thereby extending the

operational life of the telescope and

upgrading its science capability.

Assembling the International

Space Station

The ISS Node 1/Unity module was

launched on STS-88 (1998), thus

beginning the assembly of the ISS,

which required a total of 36 shuttle

missions to assemble and provide

logistical support for ISS vehicle

operations. As of October 2010,

Discovery had flown 12 missions and

Atlantis and Endeavour had flown

11 missions to the ISS, with each

mission carrying 12,700 to 18,600 kg

(28,000 to 41,000 pounds) of cargo

in the cargo bay and another 3,000 to

4,000 kg (7,000 to 9,000 pounds) of

equipment stowed in the crew cabin.

The combined total of ISS structure,

logistics, crew, water, oxygen, nitrogen,

and avionics delivered to the station for

all shuttle visits totaled more than

603,300 kg (1,330,000 pounds). No

other launch vehicle in the world could

deliver these large 4.27-m- (14-ft)-

diameter by 15.24-m- (50-ft)-long

structures or have this much capability.

ISS missions required modifications

to the three vehicles cited above—

Discovery, Atlantis, and Endeavour—

to dock to the space station. The

docking requirement resulted in the

Orbiter internal airlock being moved

externally in the payload bay. This

change, along with the inclusion of the

docking mechanism, added about

1,500 kg (3,300 pounds) of mass to

the vehicle weight.

70 The Space Shuttle and Its Operations

Kenneth Reightler

Captain, US Navy (retired).

Pilot on STS-48 (1991) and

STS-60 (1994).

“When I think about the legacy

of the Space Shuttle Program

in terms of scientific and

engineering accomplishments,

the word that comes to mind is

versatility. Each of my flights

involved so many projects and

experiments, all involving such a wide variety of science and engineering,

it seems almost impossible to catalog them. It is hard to imagine a spacecraft

other than the Space Shuttle that could accommodate such an extensive list

on just one flight.

“The shuttle’s large cargo bay could hold large, complex structures or many

small experiments, an amazing variety of experiments. We carried big, intricate

satellites as well as smaller, simpler ones able to be deployed remotely or

using robotic and/or human assistance.

“For me, as an engineer and a pilot, it was an unbelievable experience to now

be conducting world-class science in a range of disciplines with the potential

to benefit so many people back on Earth, such as experiments designed to

help produce vaccines used to eradicate deadly diseases, to produce synthetic

hormones, or to develop countermeasures for the effects of aging. I consider

it to be a rare honor and privilege to have operated experiments to which

so many scientists and engineers had devoted their time, energy, and thought.

In some cases, people had spent entire careers preparing for the day when

their experiments could be conducted, knowing that they could only work in

space and there might be only one chance to try.

“Each of my flights brought moments of pride and satisfaction in such

singular experiences.”
A Platform for Scientific

Research

The Orbiter was configured to

accommodate many different types

of scientific equipment, ranging from

large pressurized modules called

Spacelab or Spacehab where the crew

conducted scientific research in a

shirt-sleeve environment to the radars

and telescopes for Earth mapping,

celestial observations, and the study

of solar, atmospheric, and space

plasma physics. The shuttle was

often used to deploy and retrieve

science experiments and satellites.

These science payloads were:

deployed using the Shuttle Robotic

Arm; allowed to conduct free-flight

scientific operations; and then

retrieved using the arm for return to

Earth for further data analysis. This

was a unique capability that only the

Orbiter could perform.

The Orbiter was also unique because

it was an extremely stable platform on

which to conduct microgravity research

studies in material, fundamental

physics, combustion science, crystal

growth, and biotechnology that required

minimal movement or disturbance from

the host vehicle. NASA studied the

effect of space adaptation on both

humans and animals. Crews of seven

worked around the clock conducting

research in these pressurized

modules/laboratories that were packed

with scientific equipment.

Much research was conducted with the

international community. These

missions brought together international

academic, industrial, and governmental

The Space Shuttle and Its Operations 71

The crew from the International Space Station captured this view of STS-97 (2000).
partners to obtain maximum benefits

and results. The facilities included

middeck glove boxes for conducting

research and testing science procedures

and for developing new technologies in

microgravity. These boxes enabled

crew members to handle, transfer, and

manipulate experiment hardware and

material that were not approved for use

in the shuttle. There were furnaces to

study diffusion, and combustion

modules for conducting research on the

single most important chemical process

in our everyday lives. The shuttle had

freezers for sample return as well as the

72 The Space Shuttle and Its Operations

Franklin Chang-Díaz, PhD

Astronaut on STS-61C (1986), STS-34 (1989),

STS-46 (1992), STS-60 (1994), STS-75 (1996),

STS-91 (1998), and STS-111 (2002).

Memories of Wonder

“We have arrived at the base of the launch pad, dressed

for the occasion in bright orange pressure suits that fit

worse than they look. This is the day! As we enter the

service elevator that will take us 193 feet up to the level

of the shuttle cabin, we get to appreciate the size of this

ship, the mighty solid rockets that hold the gargantuan

External Tank and the seemingly fragile shuttle craft, poised

on this unlikely contraption like a gigantic moth, gathering

strength, for she knows full well where she is going today.

One by one, between nervous smiles and sheer anticipation,

we climb into our ship, aided by expert technicians who

execute their tasks with seamless and clockwork precision,

while soothing our minds with carefree conversation.

The chatter over the audio channels reverberates,

unemotional, precise, relentless, and the countdown

clock is our master. We often say that, on launch day, the

ship seems alive, hissing and creaking with the flow of

the super-cold fluids that give her life. Over the course of

3 hours, waiting patiently for the hour of deliverance,

we have each become one with the Orbiter. The chatter has

subsided, the technicians have gone. It is just us now, our

orange cocoons securely strapped and drawing the sap of

the mother ship through multiple hoses and cables. It feels

cozy and safe, alas, our comfort is tempered by the

knowledge of the machine and the job we are about to do.

‘GLS is go for main engine start...’ sounds the familiar

female voice. The rumbling below signals the beginning of

an earthquake. We feel a sudden jolt, the ship is free and

she flies! We feel the shaking and vibration and the onset of

the ‘g’ forces that build up uncomfortably, squeezing our

chests and immobilizing our limbs as the craft escapes the

pull of the Earth. And in less than 9 minutes, we are in space.

The view is the most beautiful thing we ever saw and we will

see this over and over from what is now our new home in the

vacuum of space. The days will pass and this extraordinary

vehicle will carry us to our destination...to our destiny.

It has learned to dance in space, with exquisite precision and

grace, first alone, then with other lonely dates, the Hubble

telescope, the Russian Mir station and the International

Space Station, and when the job was done, it returned to land

softly, majestically, triumphant...and ready to do it all again.”
capability to store large amounts of

data for further analysis back on Earth.

Scientists used spin tables to conduct

biological and physiological research

on the crew members.

The Orbiter provided all the power

and active cooling for the laboratories.

A typical Spacelab was provided

approximately 6.3 kW (8.45 hp)

of power, with peak power as high

as 8.1 kW (10.86 hp). To cool the

laboratories’ electronics, the modules

were tied into the Orbiter’s cooling

system so thermal control of the

payload was the same as thermal

control for the Orbiter avionics.

In an effort to share this national

resource with industry and academia,

NASA developed the Get Away

Special Program, designed to provide

inexpensive access to space for both

novices and professionals to explore

new concepts at little risk. In total,

over 100 Get Away Special payloads

were flown aboard the shuttle, and

each payload often consisted of

several individual experiments.

The cylindrical payload canisters in

which these experiments were flown

measured 0.91 m (3 ft) in length with

a 0.46-m (1.5-ft) diameter. They were

integrated into the Orbiter cargo bay

on the sill/sidewall and required

minimal space and cargo integration

engineering. The experiments could

be confined inside a sealed canister, or

the canister could be configured with a

lid that could be opened for experiment

pointing or deployment.

The shuttle was also an extremely

accurate platform for precise pointing

of scientific payloads at the Earth and

celestial targets. These unpressurized

payloads were also integrated into

the cargo bay; however, unlike the

Spacelab and Spacehab science

modules, these payloads were not

accessible by the crew, but rather were

exposed to the space environment.

The crew activated and operated these

experiments from the pressurized

confines of the Orbiter flight deck.

The Shuttle Radar Topography Mission

was dedicated to mapping the Earth’s

topography between 60° North and

58° South, including the ocean floor.

The result of the mission was a threedimensional digital terrain map of

90% of the Earth’s surface. The Orbiter

provided about 10 kW (13.4 hp) of

power to the Shuttle Radar Topography

Mission payload during on-orbit

operations and all of the cooling for the

payloads’ electronics.

An Enduring Legacy

The shuttle was a remarkable, versatile,

complex piece of machinery that

demonstrated our ingenuity for human

exploration. It allowed the United

States and the world to perform

magnificent space missions for the

benefit of all. Its ability to deploy

satellites to explore the solar system,

carry space laboratories to perform

human/biological/material science, and

carry different components to assemble

the ISS were accomplishments that will

not be surpassed for years to come.

The Space Shuttle and Its Operations 73
When taking a road trip, it is important to plan ahead by making sure

your vehicle is prepared for the journey. A typical road trip on Earth can be

routine and simple. The roadways are already properly paved, service

stations are available if vehicle repairs are needed, and food, lodging, and

stores for other supplies can also be found. The same, however, could not be

said for a Space Shuttle trip into space. The difficulties associated with

space travel are complex compared with those we face when traveling here.

Food, lodging, supplies, and repair equipment must be provided for within

the space vehicle.

Vehicle preparation required a large amount of effort to restore the shuttle

to nearly new condition each time it flew. Since it was a reusable vehicle

with high technical performance requirements, processing involved a

tremendous amount of “hands-on” labor; no simple tune-up here. Not only

was the shuttle’s exterior checked and repaired for its next flight, all

components and systems within the vehicle were individually inspected and

verified to be functioning correctly. This much detail work was necessary

because a successful flight was dependent on proper vehicle assembly.

During a launch attempt, decisions were made within milliseconds by

equipment and systems that had to perform accurately the first time—there

was no room for hesitation or error. It has been said that a million things

have to go right for the launch, mission, and landing to be a success, but it

can take only one thing to go wrong for them to become a failure.

In addition to technical problems that could plague missions, weather

conditions also significantly affected launch or landing attempts. Unlike our

car, which can continue its road trip in cloudy, windy, rainy, or cold weather

conditions, shuttle launch and landing attempts were restricted to occur only

during optimal weather conditions. As a result, weather conditions often

caused launch delays or postponed landings.

Space Shuttle launches were a national effort. During the lengthy

processing procedures for each launch, a dedicated workforce of support

staff, technicians, inspectors, engineers, and managers from across

the nation at multiple government centers had to pull together to ensure

a safe flight. The whole NASA team performed in unison during shuttle

processing, with pride and dedication to its work, to make certain the

success of each mission.

74 The Space Shuttle and Its Operations

Processing

the Shuttle for

Flight

Steven Sullivan

Preparing the Shuttle for Flight

Ground Processing

Jennifer Hall

Peter Nickolenko

Jorge Rivera

Edith Stull

Steven Sullivan

Space Operations Weather

Francis Merceret

Robert Scully

Terri Herst

Steven Sullivan

Robert Youngquist
Preparing the

Shuttle for Flight

Ground Processing

Imagine embarking on a one-of-a-kind,

once-in-a-lifetime trip. Everything

must be exactly right. Every flight of

the Space Shuttle was just that way.

A successful mission hinged on ground

operations planning and execution.

Ground operations was the term used to

describe the work required to process

the shuttle for each flight. It included

landing-to-launch processing—called a

“flow”—of the Orbiter, payloads, Solid

Rocket Boosters (SRBs), and External

Tank (ET). It also involved many

important ground systems. Three

missions could be processed at one time,

all at various stages in the flow. Each

stage had to meet critical milestones or

throw the entire flow into a tailspin.

Each shuttle mission was unique.

The planning process involved creating

a detailed set of mission guidelines,

writing reference materials and manuals,

developing flight software, generating

a flight plan, managing configuration

control, and conducting simulation

and testing. Engineers became masters

at using existing technology, systems,

and equipment in unique ways to meet

the demands of the largest and most

complex reusable space vehicle.

The end of a mission set in motion

a 4- to 5-month process that included

more than 750,000 work hours and

literally millions of processing steps to

prepare the shuttle for the next flight.

Landing

During each mission, NASA

designated several landing sites—

three in the Continental United States,

three overseas contingency or

transatlanic abort landing sites, and

various emergency landing sites

located in the shuttle’s orbital flight

path. All of these sites had one thing in

common: the commander got one

chance to make the runway. The

Orbiter dropped like a rock and there

were no second chances. If the target

was missed, the result was disaster.

Kennedy Space Center (KSC) in Florida

and Dryden Flight Research Center

(DFRC)/Edwards Air Force Base in

California were the primary landing

sites for the entire Space Shuttle

Program. White Sands Space Harbor in

New Mexico was the primary shuttle

pilot training site and a tertiary landing

site in case of unacceptable weather

conditions at the other locations.

The initial six operational missions were

scheduled to land at DFRC/Edwards

Air Force Base because of the safety

margins available on the lakebed

runways. Wet lakebed conditions

diverted one of those landings—Space

Transportation System (STS)-3 (1982)—

to White Sands Space Harbor. STS-7

(1983) was the first mission scheduled to

land at KSC, but it was diverted to

Edwards Air Force Base runways due

to unfavorable Florida weather. The

10th shuttle flight—STS-41B (1984)—

was the first to land at KSC.

Landing Systems

Similar to a conventional airport, the

KSC shuttle landing facility used visual

and electronic landing aids both on

the ground and in the Orbiter to help

direct the landing. Unlike conventional

aircraft, the Orbiter had to land perfectly

the first time since it lacked propulsion

and landed in a high-speed glide at

343 to 364 km/hr (213 to 226 mph).

Following shuttle landing, a convoy

of some 25 specially designed vehicles

or units and a team of about 150 trained

personnel converged on the runway.

The team conducted safety checks for

explosive or toxic gases, assisted the

crew in leaving the Orbiter, and

prepared the Orbiter for towing to the

Orbiter Processing Facility.

The Space Shuttle and Its Operations 75

The landing-tolaunch ground

operations “flow” at

Kennedy Space

Center prepared each

shuttle for its next

flight. This 4- to

5-month process

required thousands of

work hours and

millions of individual

processing steps.

Space Shuttle Atlantis landing, STS-129 (2009).

After landing, the Orbiter is moved to the Orbiter

Processing Facility.

Landing Orbiter Processing Facility: 120-130 days