STS-30

Flight Crew

WALKER, David Mathieson, 44, USN, commander, 2nd mission Previous mission: STS 51-A (1984)

GRABE, Ronald John, 43, USAF, pilot, 2nd mission Previous mission: STS 51-J (1985)

LEE, Mark Charles, 36, USAF, mission specialist 1

THAGARD, Norman Earl, 45, civilian, mission specialist 2, 3rd mission

Previous missions: STS-7 (1983); STS 51-B (1985)

CLEAVE, Mary Louise, 42, civilian, mission specialist 3, 2nd mission Previous mission: STS 61-B (1985)

Flight Log

The radar mapping satellite, Magellan, destined to explore the planet Venus, had been scheduled for a Shuttle launch on STS-72 on 6 April 1988, atop a Centaur-G Prime liquid-fuelled upper stage. The Challenger disaster intervened and not only delayed the mission but also meant that, for new safety reasons, the Centaur would not be carried on Shuttle. With a replacement upper stage, the less powerful IUS, Magellan was scheduled for launch between 28 April and 23 May, preferably as early as possible, but still would not reach Venus for over 16 months.

Assigned to STS-30 Atlantis, Magellan got to within 31 seconds of launching on the first launch day window, but a fault in one of the SSME fuel recirculation pumps stopped the count. Another problem was discovered later and a leaking fuel pump had to be replaced. A new launch date of 4 May was set, but Atlantis only got away with 5 minutes of the 64 minute window remaining, at 14:47hrs local time and following a hold at T — 5 minutes until the only cloud in the area – sitting over the KSC runway that would have been used for an RTLS abort – cleared and crosswinds died down.

The Shuttle performed the first ascent of its type, called an inertially targeted profile, to place Atlantis at exactly the right point for Magellan’s deployment. This did, however, result in an initial orbit of just 6.4 by 136 km (85 miles) before two OMS burns. The deployment occurred flawlessly at T + 6 hours 18 minutes, only after much in-orbit checking. Magellan’s solar panels deployed and the IUS stages fired, placing it en route. STS-30, in 28.85° orbit with a maximum altitude of 283 km (176 miles), got down to a routine job of experiments, tests and rest. But the routine was broken when the third general purpose computer on board failed and had to be replaced by

the crew – a first for the Shuttle. Once Magellan had been deployed, the crew occupied themselves with a range of mid-deck experiments.

Atlantis was aiming to make a crosswinds landing at Edwards Air Force Base at the end of its mission and such were the conditions there that it was only when the orbiter was at Mach 15 that the final choice of runway, the hard No.22, was made. Mission time was T + 4 days 0 hours 57 minutes 9 seconds.

For Magellan, the interplanetary cruise lasted from 4 May 1989 to 10 August 1990, when it entered orbit around the shrouded planet. The first mapping cycle was completed between 15 September 1990 and 15 September 1991. In an orbit with a period of 3.25 hours and an inclination of 86°, the radar mapped the surface for 37.2 minutes per orbit. In total 98 per cent of the surface of Venus was radar-mapped by Magellan, and 95 per cent of the gravity data from the planet recorded. Magellan’s extended mission lasted between 15 September and 11 October 1994. Split into cycles, the extended mission focused on: (Cycle 2) Imaging the south pole region and gaps from cycle 1; (Cycle 3) filling remaining gaps and collecting stereo imagery; (Cycle 4) measuring Venus’ gravitational field; (Cycle 5) aerobraking to circularise the orbit and global gravity measurements; (Cycle 6) collecting high-resolution gravity data, con­ducting radio science experiments and a windmill experiment to observe the behaviour of molecules in the upper atmosphere. Experiment data collection was completed on 11 October 1995. Magellan was programmed to complete a destructive entry into the Venusian atmosphere on 12 October 1994, ending a highly successful mission and closing the flight operations chapter on STS-30, over five years after the launch from Kennedy Space Center.

Milestones

125th manned space flight 59th US manned space flight

1st deployment of planetary spacecraft on manned space flight 29th Shuttle flight 4th flight of Atlantis

1st Shuttle planetary deployment mission