Spacewalks are the trickiest part of the mission. Other recent failures
Somewhere over the Gulf of Mexico on Tuesday evening, NASA carried out a flawless extraterrestrial tango as the shuttle Discovery danced closer and closer to its ungainly partner, the broken Hubble Space Telescope, 370 miles above Earth.
Seconds ahead of schedule, mission specialist Jean-Franois Clervoy artfully snagged the Hubble with Discovery's 50-foot robot arm and stowed the $3 billion telescope snugly in the shuttle's cargo bay.
The rendezvous was but the first step in a mission critical not only for NASA's public image, but also for space science - some scientists hail the Hubble as the most productive scientific instrument to date.
For NASA, the mission is as close as it gets to a sure thing - the Hubble was designed for occasional cosmic tune-ups. But with the world paying close attention after two recent failed missions to Mars and nine delays on this shuttle voyage, NASA needs the spacewalks to fix the Hubble to go flawlessly. And in the vacuum of space, just tightening a bolt can become a task of intestinal fortitude.
"All [spacewalks] are very complicated. It is a little bit like doing brain surgery while you are hanging upside down and feeling nauseous," says Bruce Margon, a University of Washington astronomer who helped design Hubble components. "With Hubble, it's even worse because it is an extraordinarily large and intricate machine."
During three long spacewalks scheduled for yesterday, today, and tomorrow, the astronauts will replace faulty gyroscopes, a broken radio transmitter, and a misguided guidance system. They will also hang stainless-steel panels over cracking insulation blankets, put in a new battery-temperature-regulation system, and give Hubble a zippier computer and hard drive.
Spacewalks, not cakewalks
While much of the replacement work will involve loosening and tightening standard Earth-issue nuts and bolts or screwing things into grooved sockets, these spacewalks will not be cakewalks.