On March 14, 1990, a Titan rocket lifted off the launch pad at Cape Canaveral carrying an Intelsat VI comsat. The satellite was destined for geostationary orbit 35,900 km above the Equator. But a malfunction in the launch vehicle left the second stage attached to the satellite and its solid rocket booster that should have been fired to raise it to high orbit. Ground controllers were later able to jettison the second stage and booster and raise the satellite into a 550-km orbit. But there it was useless. Within two days of the failed launch, Intelsat officials began to discuss with NASA the possibility of using the shuttle to rescue the satellite. And in June 1990 contracts were signed with NASA and with the satellite's manufacturers Hughes for a new booster, or kick motor, and other necessary hardware. The maiden flight of the new orbiter Endeavour was selected as the Intelsat rescue mission. The mission, STS-49, began on May 7, 1992.
It was planned to capture the satellite, attach the new booster, and relaunch it in one spacewalk.
Two further spacewalks on the mission were to be devoted to practising assembly techniques for space station Freedom. However, things didn't go according to plan. On May 10, Pierre Thuot and Rick Hieb emerged from Endeavour's airlock, as the orbiter was manoeuvred into a 'control box', a region of space where rendezvous with the Intelsat would take place. Meanwhile Intelsat controllers had been manoeuvring their satellite into the same region. This was the first time two spacecraft had been manoeuvred towards a rendezvous point in space. Slowly, Endeavour approached the Intelsat. By now Thuot was riding on the RMS (remote manipulator system) arm. The arm moved him gently in towards the gently spinning Intelsat VI, and he attempted to attach a capture bar to its underside. The idea was for him to latch on the bar and then stop the satellite's rotation by means of a kind of steering wheel mounted on the bar.
Then the RMS arm would grab the grapple fixture on the bar and lower the satellite onto the new kick motor sitting in Endeavour's payload bay.
Thuot and fellow spacewalker Rick Hieb would then secure the satellite to the kick motor, make the necessary electrical connections and activate the springs that would eject satellite and motor from the payload bay. But tampering with a spinning 5.3-metre high, 3.6-metre diameter, 4-tonne satellite a few metres away from a fragile spacecraft was never going to be easy, and so it proved. Thuot made several vain attempts to latch on the capture bar, but only succeeded in setting the satellite tumbling. He made another attempt next day, by which time Intelsat controllers had succeeded in stabilizing the satellite. Again he failed.
By this time the attempts to capture Intelsat and the spectacular pictures of the spacewalk were attracting an ever-increasing TV audience nationwide, many watching the cable channel NASA Select, which now provides continuous coverage of shuttle missions.
Clearly, a different approach was going to be needed to give any hope of capturing the satellite. And on May 12 flight controllers and crew decided that a 'hands-on' approach would be best. Three astronauts would stand in the payload bay and try to catch the satellite with their hands. Three astronauts had never been spacewalking together before on the shuttle or anywhere else. Indeed, no one knew if three people could even fit into the shuttle's airlock! Fortunately, they could. And on May 13 Pierre Thuot, Rick Hieb and Tom Akers emerged to attempt what was turning into 'mission impossible'. While they took up their positions in the payload bay, spaced out at 120 degree intervals, commander Dan Brandenstein and pilot Kevin Chilton painstakingly manoeuvred Endeavour into position less than three metres from the Intelsat. When it came within range, the three astronauts reached up and grabbed the base of the satellite with their gloved hands.
Reported Brandenstein to Mission Control: "I think we got a satellite!" After the capture bar was fixed in place, the satellite was grabbed and lowered onto the kick motor. The astronauts secured the two with clamps, connected the electrical umbilicals, and activated four springs for ejecting the satellite. They then switched on two timers for the kick motor and returned to the airlock, while the Intelsat was sprung out of the payload bay. The three-man spacewalk lasted a fraction less than 81 hours. On May 14 Intelsat controllers commanded the kick motor to fire, which it did. Soon Intelsat VI was tens of thousands of kilometres out in space and firing its on-board thrusters, which eventually manoeuvred it into its circular 35,900-km orbit. After tests, it would begin its workaday tasks of handling up to 30,000 telephone conversations and several TV channels.
