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Aviation History
1988
1988 - 2868.PDF
back in space Nasa describes the September 29 Discovery launch as "textbook" Shuttle by Julian Moxon at Kennedy Space Centre Space Shuttle Discovery returned Americans to space in copybook fashion last week, cheered on by a quarter of a million onlookers at the Kennedy Space Centre. Tension gave way to relief as Discovery flew through the point where, almost exactly 32 months before, the Challenger mission ended in a ball of flame. Moments later, the two solid rocket boosters fell away, the Shuttle and its five astronauts powering on to a 160-mile-high orbit. Given the stringent new constraints governing launch criteria, many were surprised that Discovery took off within two hours of the advertised time. Right up to the last 90 seconds it seemed inevitable that a delay would push the launch beyond the 1.30 p.m. window for September 29. The final threat—a hold at T minus 31 sec because of cabin atmos phere concerns—did not mate rialise, however, and Discovery went off at 11.37 p.m., just one minute before Challenger took off on its doomed flight in January 1986. Earlier in the day, the launch had been threatened by slacker- than-expected high-altitude winds, for which the Discovery's swivelling main engines had not been programmed. Con cerned about possible over- stressing of the airframe as the engines compensated, Nasa engineers worked up to the last minute recalculating the aero dynamic forces, finding the Orbiter still to be just within safety margins. In the event, the wind strengthened slightly immediately before launch. The only other last-minute problem of note occurred when one of the fans used to cool the astronauts' spacesuits ceased functioning. The culprit, a blown fuse, was replaced, and a supply of spares placed aboard. Six hours and 13 minutes into the flight, astronauts Frederick Hauck, Richard Covey, John Lounge, David Hilmers, and George Nelson accomplished the principle scientific objective of the mission, the release of the track ing and data relay satellite (TDRS), writes Tim Furniss. Mission specialist Mike Lounge flicked the switch that deployed the TRW-built TDRS-C and its Boeing IUS upper stage from the payload bay. The first stage of the solid- propellant IUS ignited at T+0714hr, placing TDRS into a geostationary transfer orbit, and. again at T+1225hr, completing the flight to geo stationary orbit. TDRS separa tion came at T+1306hr. Nasa engineers will be making a close study of video coverage of the Shuttle's launch, which showed an anomalous area of reddish flame appearing between the aft of the Orbiter and the external tank at about T+90sec and continuing for ten seconds. Although, at first sight, the flame appeared to emanate from the aft segment of an SRB, and was perhaps related to reduced pressure in the booster as it approached burnout at T+124sec, it is likely to have been the combustion of stag nating gases which escaped from the Space Shuttle main engines and accumulated in the area. Similar phenomena have been noticed on previous launches. Once Discovery was in orbit, the formation of ice in a flash evaporation system resulted in cabin temperatures of 32 °C. In an effort to dislodge the ice, the temperature inside the Orbiter was raised deliberately. The five-man crew was ordered to drink plenty of fluids. The flash evaporation system, operable during launch and ascent, is part of the Shuttle's active ther mal control system that circu lates cabin air. This system collects excess heat from the crew and flight- deck electronics and transfers this to space through water and Freon circulation systems, radiators, ammonia boilers, and the flash evaporators. By day two the problem appeared to have been solved, as cabin temperatures had reduced to a tolerable 21 °C. The flight continued with the operation of 11 mid-deck experiments, including a Nasa protein crystal growth experi ment which was used to grow protein crystals of a size and quality to determine the molec ular structure, which is essential for understanding protein func tions and synthesis and for drug design. The experiment included an enzyme provided by the Wellcome Foundation and the University of Oxford, which could lead to a better treatment for Aids. STS 26, the 25th spaceflight by a US Shuttle, was due to touch down on runway 22 at Edwards Air Force Base, Cali fornia, on October 3, four days after launch. Nasa's next hurdle will be to roll out Atlantis to Pad 39A for the launch of Department of Defence mission STS 27 on November 17. This will prob ably deploy an electronic- intelligence-gathering satellite codenamed Magnum, an advanced version of TRWs Rhyolite, but weighing eight times as much. A similar satellite was launched on STS 51C in January 1985. Another hurdle will be the processing of Discovery in time for the launch of STS 29 on February 18 next year to deploy TDRS D. Six further missions are planned for 1989, including two with tight planetary launch windows, for Magellan to Venus in April and Galileo to Jupiter in October. 0 The Cosmos 1900 scare is over. As promised by the Soviet Union, a radiation safety system on board the nuclear-powered satellite operated at 0008hr Moscow time on October 1, firing the power unit into a 720km-high orbit, while the instrument section, which posed no radiation danger, re entered the atmosphere on October 2 and was destroyed. 2 FLIGHT INTERNATIONAL, 8 October 1988
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