Guest Blog Post by Tom Jones | Saving Intelsat VI: Creative Problem-Solving on Endeavour, STS-49
On May 7, 1992, the STS-49 crew of seven launched on the first flight of space shuttle Endeavour, the craft built to replace the lost orbiter Challenger. The mission: rendezvous with the stranded Intelsat VI communications satellite, attach a new rocket motor, and re-launch the comsat into its useful orbit.
The mission was doubly ambitious. First, fly an untried orbiter on a critical rendezvous and rescue mission. Second, conduct a series of spacewalks to grapple the spinning satellite from orbit, lock it into a work platform, and re-equip Intelsat with its new motor.
Everything went as planned—until it didn’t. Spacewalker Pierre Thuot mounted his foot platform at the end of Endeavour’s robot arm, while Bruce Melnick maneuvered him within inches of the slowly spinning satellite. So far, so good. But as Pierre reached in to Intelsat’s base to attach a capture bar, its spring-loaded clamps failed to latch on; the attempt nudged the satellite away from Pierre in a slow wobble. Two separate EVA capture attempts were fruitless; instead of grappling the 4.8-ton satellite, the bar was shoving Intelsat away from Thuot before its clamps could find purchase. Twice, Intelsat spun away from Endeavour, leaving Pierre empty-handed and the rescue mission near failure.
Pilot Kevin Chilton told me, “We had to come up with a better plan.” He gazed out the back windows on the flight deck, and “As God as my witness, an Air Force class called ‘Problem Solving’ came into my mind. I couldn’t remember all the steps, but I remembered Step 1: Define the Problem.”
The crew talked over what they’d seen. They figured that as Pierre pushed the bar against Intelsat’s base, the satellite moved ever so slightly away, far enough to prevent the bar’s claws from grabbing the circular rim. Step 1 of Problem Solving.
To solve that problem, we had to keep the satellite from moving away while Pierre applied the capture bar. On to Step 2: Inventory Your Assets. Said Kevin, “We looked outside and asked ourselves, ‘What do we have in the cargo bay that don’t ordinarily have on the shuttle?’ We asked the same question about the inside…We had extra spacesuits. We went through all the different things we had at hand, including a tool inventory. It reminded me of the scene in the movie, Apollo 13, where they come in with a box of stuff and dump it on the table and [flight director] Gene Kranz says, ‘I suggest you gentlemen invent a way to put a square peg in a round hole. Rapidly.’”
Chilton and his crewmates moved on to the next step in problem solving: Brainstorm. Bruce, the arm operator, said, “Why don’t we put three people out?” “What an out-of-the-box thought!” Kevin told me. “The team dynamic was really magical.”
The crew stayed up all night and worked out a detailed plan, trying to imagine all the objections the ground might raise to quash it. Commander Dan Brandenstein let his crew’s creativity flow, letting the best ideas float to the center of the discussion. Next morning, they called Houston with the three-astronaut-EVA proposal—a spacewalk that had never been attempted. The space and ground teams agreed that a manual hand-capture of Intelsat would give them their best shot at success.
Emerging the next day from the cramped airlock designed for only two spacewalkers, Tom Akers joined teammates Rick Hieb and Pierre outside. The trio positioned Thuot on the robot arm, with Hieb and Akers on two work platforms at the center of the payload bay. With only enough fuel for one final rendezvous attempt, Brandenstein and Chilton brought Endeavour up below Intelsat, stabilizing within feet of the slowly spinning, wobbling comsat. Although the shuttle and satellite were both orbiting at 17,500 mph, Intelsat appeared to hover over the spacewalkers as Brandenstein brought the satellite within arm’s length.
“Three, two, one, capture!” Six hands grasped Intelsat’s slowly rotating base, stopping its spin. [I witnessed the grab from Mission Control in Houston.] Hieb and Akers held on while Thuot finally got the capture bar in place, enabling the crew to maneuver the satellite onto its waiting booster. Within hours, the crew’s outside-the-box thinking resulted in a successful redeployment of the satellite, which soon arrived in its geosynchronous working orbit.
Chilton observed, “All the things that went wrong, the team overcame. The various problems that had to be solved by both the crew on orbit and on the ground—I don’t think there’s been another mission that ended successfully that compares.” STS-49’s improbable success is testament to the power of improvisation, free thinking, and leadership willing to let the team’s best ideas gel into a practical, executable plan.
Adapted from Space Shuttle Stories, to be released on Oct. 31, 2023 by Smithsonian Books.