Altered priorities

The mission roster was hurriedly rejigged to work around the TDRS problems, and Challenger's STS-7 flight launched a pair of ^ | „y (

communications satellites in April. W *

It also released the German-built Shuttle Pallet Applications Satellite (SPAS), a temporary satellite designed to float free of the Shuttle. Recapturing the SPAS at the end of the mission provided experience that would be useful i when the shuttle needed to retrieve larger satellites from orbit for servicing (see p.201). The same problems were addressed on the next mission, STS-8, where alongside the Indian satellite lnsat-1B, Challenger carried a heavyweight dummy satellite to allow testing of the manipulator arm under stress.

While most of these flights carried small-scale experiments in the orbiter's mid-deck, the first full-scale science mission was Spacelab 1, carried aboard Columbia for the STS-9 launch in November 1983 (see p.198). A change in the numbering it'

system meant that the tenth Shuttle mission ^^ was Challenger's STS-41B. Two satellites were ^^ successfully deployed, only for their Jj^KS? Payload Assist Modules (smaller, lower-powered equivalents of the IUS) to malfunction. However, the W Manned Maneuvering Unit (MMU)

\ translationol hand was successfully tested, permitting controller propels the fjfSt untethered spaCewalk. ostronout through space

MANNED MANEUVERING UNIT

The MMU uses the controlled release of gaseous nitrogen propellont (GN2) to allow an astronaut to fly free in space. The pack contains two independent propulsion systems, each with its own GN2 tanks and set of four "triad" thrusters (each a set of three nozzles allowing the escaping gas to ) push the astronaut around three axes).

SATELLITE RELEASE

TORS-A sits atop a pivoting turntable in the Shuttle cargo bay just prior to its release into orbit on Challenger's STS-6 flight. The problematic IUS rocket stage is shrouded in gold foil beneath the satellite.

FLYING FREE

Bruce McCondless somersaults above Challenger's cargo bay during a test of the MMU. In his hands he carries the Trunnion Pin Attachment Device (TPAD), a piece of equipment that, when attached to a satellite, allowed it to be grasped by the Shuttle's robot arm.

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SALLY RIDE

Challenger's STS-7 mission finally put an American woman in space, more than two decades behind the Soviet Union. In 1978, Californian physicist Sally Ride (b.1951) joined NASA in the first astronaut class to accept women. She worked on the Shuttle's robot arm and as Capcom for early Shuttle missions before finally getting a chance to fly.

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TECHNOLOGY

AMERICA'S SPACEPLANE

vertical stabilizer crew A maximum of seven length 37.24m (122ft 2Viin)

height 17.27m (56ft 8in)

wingspan 23.79m (78ft ttin)

weight at launch 99,318kg (218,958lb)

engines (orbital) 2 X OMS main engines (hydrazine/N204) 44 X RCS thrusters (hydrazine/N204)

operating altitude 300-620km (185-385 miles)

Shuttle orbiter main contractor North American Rockwell hydrazine and nitrogen tetroxide tanks

Orbital Maneuvering System housing

Aft fuselage oft bulkheod

OMS engine aft Reaction Control System main engine body flap for pitch control in atmosphere elevon for manoeuvres in atmosphere main engine fuel supply system

TECHNOLOGY

AMERICA'S SPACEPLANE

vertical stabilizer crew A maximum of seven length 37.24m (122ft 2Viin)

height 17.27m (56ft 8in)

wingspan 23.79m (78ft ttin)

weight at launch 99,318kg (218,958lb)

engines (orbital) 2 X OMS main engines (hydrazine/N204) 44 X RCS thrusters (hydrazine/N204)

operating altitude 300-620km (185-385 miles)

Shuttle orbiter

SHUTTLE ENGINE TEST

The Space Shuttle Main Engines are extremely complex and are fuelled by high-speed turbopumps that draw propellants from the External Tank. Temperatures in the combustion chamber can reach 3,300°C (6,000°F).

main contractor North American Rockwell hydrazine and nitrogen tetroxide tanks

Orbital Maneuvering System housing

Aft fuselage oft bulkheod

LANDING PROCEDURE

The Shuttle begins its descent by turning backwards in its orbit and using the OMS engines as retro-rockets. It then turns again for re-entry, angling itself so that the heat-resistant ceramic tiles on the underside take the brunt of friction. Once it has slowed to merely supersonic speeds, it is effectively the world's heaviest glider, and gets only one chance at landing. Landing at high speed, it needs a very long runway for its parachute-assisted braking.

The size of a short-haul jet airliner, the Space Shuttle orbiter is by far the largest spacecraft ever launched into orbit. Although its main engines are used only during launch, a complex system of secondary thrusters and manoeuvring engines gives the orbiter mobility and versatility in orbit. The payload bay can carry up to two satellites or the Spacelab laboratory into orbit, while the Remote Manipulator System is used for satellite deployment or retrieval and for rudder/speed orbital construction tasks. brake

OMS engine aft Reaction Control System main engine

ORBITAL THRUSTERS

The two pods at the bock of the Shuttle carry its Orbital Maneuvering System (OMS) engines - a pair of engines derived from the Apollo Service Module engine that allow the Shuttle to moke orbital corrections and the retroburn for re-entry. They also contain thrusters for the Reaction Control System (RCS), which orients the Shuttle in space.

main engine fuel supply system body flap for pitch control in atmosphere elevon for manoeuvres in atmosphere

THE VIEW FROM ABOVE

The orbiter always opens its payload bay doors after reaching space - their interiors function as radiators that help regulate the spacecraft's temperature. In this photograph from August 2001, Discovery is approoching the International Space Station, carrying the Itolian-built Multi-Purpose Logistics Module - a cargo container for the ISS.

Mid-fuselage low-temperature thermal insulation payload boy doors nose landing gear high-temperature thermal insulation

Mid-fuselage low-temperature thermal insulation payload boy doors

SHUTTLE ORBITER WITH SPACELAB

This illustration of the Shuttle shows the ESA-built Spacelob module occupying much of the payload bay. Because the orbiter's underside is more effective at blocking radiation from space than the upper side, the Shuttle usually operates upside-down, with the cargo bay facing Earth.

nose landing gear high-temperature thermal insulation

SPACELAB INSTALLED

Spocelob and its access tunnel are fitted in Columbia's cargo bay during preparations for the STS-9 mission.

Shuttle outside of the Spacelab programme.

BIOGRAPHY

ULF MERBOLD

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