However, his efforts exhausted the Shuttle's fuel budget for the operation and Flight Director Bill Reeves called off the attempt at 10 pm, instructing Kregel to manoeuvre to a separation distance 64 km 'behind' Spartan; already, by this time, flight controllers had in the backs of their minds a plan to re-rendezvous with it on 24 November and send Scott and Doi out on a spacewalk to manually grab it. ''We feel very confident this is going to work [and] the crew is quite capable of doing this,'' senior flight director Bob Castle told journalists on the 22nd.
''The flying tasks of bringing the orbiter up close to the tumbling spacecraft I think are very doable.'' Although the Spartan rescue was only expected to require a couple of hours, the decision was taken to run the spacewalk to the planned six hours and have Scott and Doi complete most of the other tasks they had originally trained for. After checking out their equipment, the duo began donning their spacesuits, with Chawla's assistance, around 9 pm on 24 November, as Kregel and Lindsey continued a series of thruster firings to gradually close the gap between Columbia and Spartan.
The most critical manoeuvre, known as the 'Terminal Initiation' burn, came at 10:51 pm and placed the Shuttle on an intercepting path to arrive directly beneath the slowly rotating satellite. A couple of minutes past midnight, the duo became the first astronauts to vacate Columbia's airlock in space - prompting Doi to remark on a ''nice view over the Earth'' - and quickly moved to their positions at either end of the MPESS carrier as Spartan tumbled slowly 210 m away. When Kregel had positioned Columbia within reach, he radioed the two spacewalkers, giving them a 'go' to grab the satellite.
''Winston,'' he told Scott, ''I think if we're patient, it looks like the telescope is rotating, the top end of the longitudinal axis looks like it will come down to you and the bottom one right up to Takao. If we just wait, it'll come right to us.''
''Okay, copy that, Kevin,'' Scott replied. ''We'll just be patient and see what happens.'' A few minutes later, the elation was clear in his voice as the satellite tumbled closer. ''It's perfect: the telescope is right between us! It's maybe four feet above my head.'' According to Kregel, Spartan appeared to be relatively stable throughout the rendezvous, which suggested its backup attitude-control system had activated at some point after Columbia's departure on 21 November, damping out the two-degrees-per-second rotation to leave a much more tumbling motion.
Right on cue, at 2:09 am, as they flew over the southern Pacific Ocean, the two spacewalkers reached out and grabbed the satellite. ''Okay,'' said Scott, ''now that we've got it, Mr Doi, let's decide what we're going to do with it.'' They did have some difficulty in manually latching it back onto its MPESS carrier, but Chawla, operating the RMS from Columbia's aft flight deck, succeeded in driving it onto its
retention latches. "KC's got it!" radioed Kregel. "You guys can let go." The entire procedure was over by 3:23 am, with Spartan snared in the payload bay.
Winston Scott (left) and Takao Doi get themselves into position to grab Spartan-201 with their gloved hands.
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