The Ground- page 2 | Space | Air & Space Magazine
Tough under pressure: Space station flight director Mark Ferring at his console during last year's STS-114 mission. (NASA)

The Ground

Astronauts get the glory, but flight directors run the show.

Air & Space Magazine | Subscribe

(Continued from page 1)

Shuttle simulations might last three or four days, and to get certified to work an actual launch and landing, a flight director may have completed hundreds of simulations before doing it for real. “They give you all these failures—to the point where it is almost unrealistic—to see how we’ll react,” says Ridings.

Still, even after hundreds of hours of practicing far-fetched disaster scenarios, real missions occasionally serve up surprises. One frequently cited by flight directors is the March 1992 STS-49 mission to rescue an Intelsat communications satellite stranded in an unusable orbit. The shuttle crew’s task was to attach a new rocket motor to the satellite that would boost it to the proper altitude. The original plan had been for a spacewalking astronaut at the end of the shuttle’s robot arm to snare the satellite with a special capture bar and bring it into the shuttle cargo bay. When that failed several times, the astronauts themselves proposed a workaround: Send out three spacewalkers, which had never been tried before, to grab the two-ton beast by hand and coax it into the bay.

It worked. But after the astronauts attached a booster rocket to the satellite and reentered the shuttle, another glitch occurred. When the crew flipped a pair of switches to activate a spring that would eject the satellite from the shuttle, nothing happened. “Now we’re sitting there with a satellite in our payload bay, with a rocket motor that might be getting ready to fire off,” recalls Phil Engelauf, who was a flight director for the mission.

Stumped by a potentially dangerous situation they’d never trained for, the ground controllers set to work. Engelauf remembers Jeff Hanley, then a mission control payload officer responsible for the vehicle’s cargo, poring over the shuttle’s wiring diagrams. “He was sitting in front of me with these long, fold-out drawings tracing through the entire system,” says Engelauf. Hanley had a hunch: The arming and firing circuits could have been wired backward. “Instead of arming the A circuit and firing the B circuit, Hanley wanted to arm the B circuit and fire the A circuit. So we read the instructions up to the crew and I remember you could cut the tension and suspense with a knife as we counted down…three…two…one…fire…

and sure enough, the satellite left the payload bay.”

Intuition like Hanley’s amounts to a sixth sense, says Gene Kranz, the legendary NASA flight director who handled mission control’s most famous “save” after an oxygen tank on the Apollo 13 spacecraft exploded on the way to the moon in 1970. “There’s a gut feeling, an almost intuitive response to things that are happening around you,” he says. “It’s like chess,” says former astronaut and NASA head of spaceflight Bill Readdy. “You have to always think several moves ahead.”

So it was with an emergency on the space station on Super Bowl Sunday, February 3, 2002. When a software glitch took down the station’s Russian-run computers shortly before midnight, there wasn’t much Bryan Lunney, the flight director on duty, could do but watch and wait. The Russian computers fed data to the station’s gyroscopes, which were essential for holding the station’s position stable. Two hours after the first computer failed, the backup system also crashed. “We’d seen similar things in the past,” says Lunney, whose father was the Apollo-era flight director Glynn Lunney. “It’s normally no big deal. But when the second computer failed, we started thinking about what to do if the third one failed too.”

Sure enough, the third computer also shut down. With data no longer being supplied by its gyroscopes, the ISS began a very slow tumble. Consequently, the huge solar arrays were no longer pointing at the sun. And without a steady supply of solar-derived electricity, the controllers knew things would get dark and cold pretty fast. “If the station runs out of power, that’s bad,” says Lunney. “There is no good way to jumpstart it.”

Not sure how long the computers would be down, and never having trained for a triple-computer failure, Lunney turned for help to his PHALCON (power generation, storage, and power distribution) flight controller, who offered a simple, almost primitive solution: Have the crew look out the window, find the sun, then manually rotate the arrays toward the light. “He came up with this procedure on the fly,” says Lunney. “It had never been done before.”

The PHALCON controller devised a crude table that divided the station into four viewing areas—deck, forward, overhead, and aft—with corresponding angles for each section. For example, if the sun was visible through the aft portal, the crew should tilt one solar array to 90 degrees and the other to 270. Because radio communications on the drifting station were also intermittent, mission control would have less than five minutes to read the instructions up to the astronauts. “We practiced reading it aloud a couple of times to see how long it took,” remembers Lunney. “I was nervous and the adrenalin was certainly flowing.” But the solar arrays eked out enough juice to keep the station powered up until the Russians finally got their computers back online. Visible relief swept through mission control. Says Lunney, “I felt like a fireman who’d walked out of a burning house having just rescued the kids from the bedroom.”

Comment on this Story

comments powered by Disqus