In the early morning of February 3, 1984, the shuttle Challenger rumbled into space on what was expected to be a routine mission, carrying two satellites built by the Space and Communications Group of Hughes Aircraft Company.
The routine, however, was broken only hours later. After being ejected form the shuttle’s payload bay according to plan, Westar VI for Western Union automatically fired it perigee keep motor—which terminated prematurely.
The short burn left Westar VI in an elliptical transfer orbit with a high point far below the intended 22,300-mile zenith necessary for a geosynchronous operating orbit.
Three days later, the second satellite, Palapa B2 for Indonesia, was ejected flawlessly from the shuttle. Again, an onboard timer fired the perigee kick motor. Again, a short burn placed the satellite in an errant orbit similar to that of Westar VI.
Earlier shuttle flights had successfully placed SCG spacecraft into orbit, but the events of Mission 41-B left the two communications satellites circling Earth uselessly and set the stage for one of man’s most ambitious and dramatic space adventures.
Recovery planners at SCG were faced with a complex problem; how to rid the satellites of their onboard fuel, including powerful apogee kick motors, while placing the craft in orbits that could be modified for a rendezvous with the space shuttle in November, nine months distant.
An Orbital Operations and Analysis team headed by manager Jerry Salvatore developed a scheme. Westar VI was precisely oriented and on May 12 its apogee kick motor was fired. The firing not only expended the potentially dangerous solid fuel, but boosted the satellite into a near circular orbit some 700 miles above Earth.
Four days later, the procedure was tried on Palapa B-2, and the satellite settled into a slightly higher near-circular orbit.
By boosting Palapa B-2 about 50 miles higher than Westar VI, Salvatore and his team relied on Earth’s gravity to pull more strongly on Westar VI during the next 10 weeks and help bring the orbital planes of the satellites together.
The scheme worked, and the Operations and Analysis team used the satellites’ thrusters to nudge them into nearly the same 650-mile high orbit by early August.
What followed was “the most complex unmanned orbital acquisition ever attempted,” said Salvatore.
“Consider trying to point a pencil beam at an object that is streaking across the sky, locking on to it, transmitting commands, executing them, and verifying that we did what we set out to do—all in a matter of minutes. Then, try repeating that 600 times for four consecutive weeks on two different spacecraft.”
Starting on October 9, the Operations and Analysis team generated those commands and meticulously lowered the satellites to an orbit only 225 miles high. Two thimble-size thrusters on the back end of each satellite were fired 55 times to complete the orbital transfer maneuvers. The commands went from the Operations Control Center at Hughes Communications in El Segundo to a network of nine tracking stations around the world.
By the November 8 launch of shuttle Discovery on Mission 51-A, Westar VI and Palapa B2, their stabilizing spins reduced to 2 revolutions per minute, were ready to be brought home after spending nine months orbiting the Earth more than 3800 times.
After chasing Palapa B2 around the earth for 1.6 million miles, Discovery was in a position on November 12 to begin history’s first space salvage operation.
Mission Commander Frederick Hauck and Pilot David Walker steered Discovery to within 35 feet of Palapa B2 as the winged spaceship and the satellite flew in tandem at 17,500 miles per hour.
“There sure isn’t any problem seeing this baby,” said Hauck, as sunlight glistened off the Palapa B2 solar panels.
At 5:32 am Pacific Standard Time (PST), Astronaut Joseph Allen used his jet-powered backpack to glide over to the slowly rotating Palapa B2 as Baja California appeared 225 miles beneath him.
With a 5-foot long probe attached to the tummy of his manned maneuvering unit, Allen flew to the back end of the satellite. With little effort, he inserted the probe, nicknamed a stinger, into the exhaust nozzle of the satellite’s spent apogee motor. A pull of a lever released three flanges at the end of the stinger, much like an umbrella opening inside a chimney..
“Stop the clock, I’ve got it tied,” Allen said as he brought the satellite to a standstill.
Operating controls inside the cabin, Astronaut Anna Fisher eased the shuttle’s 50-foot long mechanical arm toward Allen and latched onto the stinger. She brought the satellite, with Allen attached, over to the cargo bay where Astronaut Dale Gardner. The mission’s other spacewalker, snipped off the Palapa B2 telemetry and command antenna with a pair of garden shears so the payload bay doors could be closed for the shuttle’s return to Earth.
Gardner was supposed to attach an A-frame device across the top of the satellite’s fragile main antenna to give the mechanical arm some pace to grab, but an unexpected protrusion kept the bracket from holding fast.
“it’s not a piece of structure I can remove. I’ve tried cutting it and twisting it, everything I can think of,” a distressed Gardner said. “Close doesn’t count.”
The astronauts abandoned the A-frame and went to a pre-rehearsed Plan B: they would wrestle the satellite into the cargo bay manually. After removing the stinger from the satellite, Allen climbed into a foot restraint on the side of the cargo bay, struggling to turn and steady the 9-foot long Palapa B2. For 90 minutes, Allen held the satellite over his head as Gardner first fitted a “shower cap” over the rocket nozzle to carbon particles from floating out, then attached a berthing adapter designed and built by an SCG recovery team led by Jack Juraco, hardware project manager.
Gardner had little trouble tightening the nine clamps on the adapter, a “most critical piece of equipment” that had no backup in the event of a failure, Juraco said.
“Joe Allen now qualifies as the first human in history to hold a 1200 pound communications satellite over his head for one trip around the world,” quipped a spokesman at NASA Mission Control as Allen, the smallest male astronaut at 5 feet, 6 inches, constantly fought the inertia of the satellite.
Finally, near six hours after the space walk began, Gardner called out: “All right! We got it!” as Palapa B2 and its berthing adapter were guided into three latching mechanisms on a platform built by Juraco’s team.
Dr. David Braverman, associate manager of SCG’s Commercial Systems Division, said a late adjustment to a component on Palapa B2 created a protrusion that prevented the attachment of the A-frame. The adjustment was not reflected in the drawings.
That problem aside, Braverman said he was “terribly excited” about the recovery. “That was one of the hardest things in terms of orbital maneuvering that has ever been done,” he stated.
With Palapa B2 safely onboard, Hauck and his crew went after Westar VI, which was more than 600 miles away.
The astronauts decided to forgo the A-frame antenna bridge of the Westar VI recovery, even though it was believed they would not encounter the dame problem. They would bring Westar VI in manually.
With surprising ease brought on by the sureness of experience, Allen and Gardner on November 14 recovered Westar VI so swiftly and smoothly that they ran an hour ahead of schedule.
The Westar VI salvage began at 4:22 am PST as Discovery passed over the Caribbean. This time, Gardner donned his maneuvering unit, replete with stinger, and jetted 35 feet to the satellite.
Easing the stinger into the satellite, Gardner locked on to Westar VI and brought it under control with the thrusters of his jet pack. “I got it,” Gardner called out. “Joe, it’s just like you said.”
While Gardner held on to the base of the satellite, Fisher extended the mechanical arm out from the shuttle to Westar VI. But instead of grabbing the stinger, this time she had Allen perched at the end of the arm.
Allen reached out and grabbed Westar VI by its telemetry antenna. Then Fisher, working by remote control in the cabin brought Allen, Gardner, and the satellite back to the cargo bay.
Standing on the arm allowed Allen to hold the satellite straight out instead of over his head as on Palapa B2. “It’s much easier with the arm,” he told Mission Control.
Working underneath the satellite, Gardner attached the berthing adapter and provided a bit of excitement to an otherwise smooth recovery operation. While tightening the adapter’s nine clamp shoes, he dropped his torque wrench, which flitted across the cargo by. He shot across to retrieve it, saying, “I just hate to lose my tools.”
Once the adapter was attached, the mechanical arm, with Allen on for the ride, lowered Westar VI snugly into its locking mechanisms. Then Allen used the shears to snip off the antenna he had been holding on to.
“We have two satellites locked in the bay,” Hauck told Mission Control. “Super job, guys,” Mission Control radioed back.
“Credit Mr. Salvatore at Hughes,” Gardner said. “The spacecraft was right where it was supposed to be and the spin rate was perfect.”
On the ground, Salvatore saw the months of work by the SCG teams pay off. “After nine months, I think I know what it’s like to deliver twins,” he said. “Dreams do come with a labor of love.”
Discovery landed at the Kennedy Space Center in Florida at 4 am PST on November 16. Ending a mission that Braverman said was a “sign of a beautiful and well-rehearsed effort.”
“The scores of people at Hughes who dedicated countless hours to the mission should be very proud of their contributions,” Juraco added. “It has been a great honor to have been part of such a tremendous triumph.”