The Shuttle system

liquid oxygen vent valve and fairing external tank liquid oxygen tank

The final version of the Space Transportation System (STS) was a compromise born of necessity. The US military's need for a sizeable orbiter to launch its largest payloads made it impossible to design a fully reusable system, but the Shuttle is at least largely reusable. In addition to the Shuttle orbiter itself (see pp.196-97), there are three other elements - a large External Tank (ET) and two side-mounted Solid Rocket Boosters (SRBs). Each of these plays an important role in getting the Shuttle orbiter into space.

drogue parachute

3 Shuttle rolls to inverted position slosh baffles main parachute pack nose cap

2 X SRBs, 3 X SSMEs total thrust at lift-off 3.55 million kgf (7.8 million Ibf)

SRB: Thiokol; ET: Lockheed Martin; SSME: Rocketdyne main contractors

Solid Rocket Booster liquid hydrogen tank

SHUTTLE LAUNCH SYSTEM

During launch, the Space Shuttle Main Engines (SSMEs) draw propellants from the External Tank, and two Solid Rocket Boosters help to get the Shuttle moving. The boosters fall away first, then as the Shuttle nears orbit, it also discords the External Tank.

systems tunnel aft attach ring

STACKING THE SHUTTLE

The Shuttle system is put together at Kennedy Space Center's Vehicle Assembly Building. The boosters and External Tank are mounted on top of the Mobile Launch Platform (see opposite). The orbiter arrives from its separate processing facility and is hoisted high into the air and lowered into place.

Space Shuttle main engine (SSME)

solid rocket motor solid rocket motor nozzle extension

8 main engines continue to fire, fuelled by ET attached to orbiter

9 ET separates, orbiter may roll upright

5 SRB drogue chutes deploy

9 ET separates, orbiter may roll upright

6 SRB main chutes deploy, drogue shoots jettison

7 SRB and parachutes splash down for retrieval at sea

6 SRB main chutes deploy, drogue shoots jettison

10 orbiter operates in low-Eorth orbit for up to 30 days

11 orbiter prepores to turn for re-entry

11 orbiter prepores to turn for re-entry

SHUTTLE MISSION PROFILE

The Shuttle launches from Kennedy Space Center in Florida, typically into an inclined low Earth orbit. As it climbs it discards the Solid Rocket Boosters, which descend on parachutes and are recovered from the Atlantic Ocean. The External Tank is discarded far higher in the atmosphere and burns up as it falls. Depending on weather conditions at KSC, the Shuttle may return to a wide range of different landing sites, but the costs of transportation back to Florida are very high.

15 orbiter touches down like an aircraft

12 orbiter turns backwards, and retrorockets fire to reduce speed

12 orbiter turns backwards, and retrorockets fire to reduce speed

13 orbiter turns again as it enters Earth's atmosphere

14 orbiter glides to landing site

14 orbiter glides to landing site

ATLANTIS STACK ROLL-OUT

A spectacular view from the roof of the Vehicle Assembly Building shows the fully assembled Space Shuttle Atlantis on top of its Mobile Launch Platform and ready to move to the launch pad.

CRAWLER TRANSPORTER

The Shuttle is assembled on top of a Mobile Launch Platform (MLP), which is then picked up by a powerful mobile tractor unit for transport to the pad. The entire assembly weighs 8,170 tonnes (18 million lb) and moves at a top speed of 1.6kph (Imph).

FIERY LAUNCH

The pillar of flame on which the whole Shuttle assembly rises into the sky comes largely from the two Solid Rocket Boosters - the exhaust from the Space Shuttle Main Engines is much hotter, blue, and almost transparent.

1 Shuttle assembled in l/AB and rolled out on MLP

16 orbiter uses drogue chute and brakes as it touches down

7 SRB and parachutes splash down for retrieval at sea

1 Shuttle assembled in l/AB and rolled out on MLP

16 orbiter uses drogue chute and brakes as it touches down

BIOGRAPHY

JOHN YOUNG

BIOGRAPHY

JOHN YOUNG

LIFT-OFF!

With its three SSMEs and two SRBs firing simultaneously, Columbia blasts free of Pad A at Launch Complex 39 on its maiden mission. The dote, 12 April 1981, marked the 20th anniversary of Yuri Gagarin's first manned spaceflight.

12 April 1981

Columbia launches from Cape Canaveral on its maiden flight.

14 April 1981

Columbio returns to Edwards Air Force Base, landing on a dry lake bed.

Wings into orbit

Developing a spacecraft as complex as the Space Shuttle inevitably took longer than planned, but after a variety of tests, the Shuttle was finally ready for its maiden launch in 1981.

MAIDEN FLIGHT

Columbia arrives for duty at the Kennedy Space Center, Cape Canaveral, piggybacked on a converted 747 carrier aircraft. The aerodynamic tailcone over the Shuttle's main engines reduces turbulence.

28 April 1981

The Shuttle orbiter returns to Cape Canaveral for processing and repairs.

12 November 1981

Columbia is launched on its second test flight.

14 November 1981

Columbia returns to Earth early, landing again on the lake bed at Edwards.

22 March 1982

Columbia is launched on its third test flight.

Although NASA was given the go-ahead to build the Space Shuttle in the early 1970s, a host of issues needed to be solved before construction work could even begin, and optimistic hopes of a first flight in 1977 were soon being revised.

One significant cause of delay was the question of military use. In order to provide the predicted savings in launch costs, the Shuttle would have to fly regularly, with perhaps one mission every two weeks. The demand for such frequent flights would only be there if the US totally abandoned unmanned launches, including those for military payloads. For this reason, the Air Force agreed to contribute to development costs - but it extracted a heavy price in return. The entire spacecraft would have to be larger to carry military payloads. It would have to be capable of operating from the USAF's launch site at Vandenberg Air Force Base. And the USAF would be guaranteed a number of launch slots every year.

With all these issues taken into account, work on the prototype Shuttle orbiter, originally to be known as Constitution, got under way in June 1974.

0 0

Post a comment