When orbiter Discovery streaked from the launch pad on November 8, 1984, it was embarking on the most daring shuttle mission yet. The crew, after launching two comsats into orbit, which was routine, would then attempt to capture two comsats already in orbit and return them to Earth for repair. Nothing like it had been attempted before. The two comsats in question, Palapa B2 and Westar VI, each worth about $75 million each, had been deployed in orbit on the STS-41B mission in February 1984. But when their PAM (payload assist module) rocket motors failed to ignite, they had become stranded in useless low orbits instead of being boosted into high geostationary orbits. Prior to the launch of Discovery, the two satellites had been manoeuvred into orbits about 340 km high to be accessible to the shuttle. There was no problem about rendezvousing with the satellites, that was routine. The problem was how to get hold of them. The Solar Max satellite successfully captured on an earlier mission (STS-41C) was fitted with a purpose-built grappling fixture, which the shuttle RMS (remote manipulator system) arm could grip. The two comsats, however, had no such fixtures. While thinking about this problem, Dale Gardner, one of the astronauts who would be involved in the capture, came up with an ingenious idea. He suggested using a purpose-built gadget that could be inserted into the booster motor of each satellite and then lock. The device would carry a grapple fixture which the RMS arm could hold. It came to be called an apogee kick motor device, immediately nicknamed the 'stinger'. On day five of the mission, November 12, Discovery chased and rendezvoused first with the Palapa. Joseph Allen and Gardner went EVA to attempt capture. While Gardner anchored himself in the payload bay, Allen flew over to the comsat in an MMU (manned manoeuvring unit). He locked the stinger in place and then fired the MMU's thruster jets to stop the spacecraft spinning before disengaging. RMS controller Anna Fisher gripped the grapple fixture on the stinger and repositioned the satellite over the payload bay. Gardner then removed the aerial on top of the satellite and tried to fix another grapple fixture frame over it. But it didn't fit, and so Fisher couldn't use the RMS arm to hold the satellite steady for the remainder of the operation. So it was left to Allen to hang onto Palapa by hand, while Gardner removed the stinger and prepared it for berthing in a cradle in the payload bay. Allen created a novel space record: holding onto a satellite for a complete orbit of the Earth! Afterwards both astronauts manhandled Palapa into its cradle and secured it. Next day the astronauts rested while Discovery chased Westar VI, which was in a similar orbit but 1100 km ahead. Then Allen and Gardner went out to recapture it, deciding to use exactly the same procedure as before. But this time Gardner flew the MMU and stinger over to the satellite. Allen repeated his gripping performance, after which Westar was securely berthed. Reported mission commander Frederick Hauck to Mission Control: "We've got two satellites locked in the bay." Lloyd's of London, the insurers of the satellites, were delighted. They rang the famous Lutine Bell, a tradition following a successful salvage, but usually of a ship at sea. They later awarded Discovery's crew the Lloyd's Silver Medal for their unique salvage operation. NASA too were jubilant at the expertise of their spacewalking astronauts and the versatility of their space shuttle.
