Astronauts took a fifth and final spacewalk Monday night to fix the Hubble Space Telescope’s torn insulating cover with bits of foil, wire, clips, plastic twists and parachute cord.
Mission Control added the spacewalk to shuttle Discovery’s flight so Mark Lee and Steven Smith could hang quilt-like patches over splits in Hubble’s thin, reflective insulation, apparently damaged by sun exposure during seven years in orbit.
The crew discovered the damage last week while installing state-of-the-art scientific gear that will allow the telescope to look deeper into the universe.
With the sort of ingenuity used on Apollo 13, the crew cobbled together the patches early Monday as Gregory Harbaugh and Joe Tanner installed the last of Hubble’s replacement parts, and did a little mending too.
Working 375 miles above Earth, Harbaugh and Tanner covered two gaping holes near the top of the 43-foot telescope with pieces of Teflon-coated material 3 feet long and 1 foot wide. They attached the blankets, brought along to repair possible pinholes, to knobs and rails with wire and string.
The task of hanging the homemade patches over the lower electronic compartments was considered more difficult and more critical. The astronauts salvaged the material, meant for just such a problem, from the cargo bay.
NASA managers were relieved at how well the first repairs went. “It was a good feeling,” said Mike Weiss, a Hubble service manager.
The repairs were nowhere near as crucial as those performed during Apollo 13’s aborted moon mission in 1970. The three astronauts saved their lives by using tape and the cardboard covers torn from their flight manuals to restore the spacecraft’s system for cleansing the air of carbon dioxide.
Hubble, in fact, probably could have made it to the next service call in late 1999 without the insulation repairs, NASA payload manager Kenneth Ledbetter said. The concern was that the deteriorating cover might cause sensitive electronics in the $2-billion telescope to overheat and fail.
“It was something we felt was prudent to do--not absolutely necessary, but prudent to do, and we did it,” Ledbetter said.
Harbaugh and Tanner were proud of their handiwork. They spent 1 1/2 hours attaching two blankets and adjusting them just so.
“What do you think?” Harbaugh asked, backing away.
“Like it. Looks good from here,” Tanner replied.
Mission Control put it this way: “A masterpiece.”
NASA plans a more permanent fix during the next service call in three years. The astronauts snipped off a piece of the damaged insulation to bring back home for analysis.
The astronauts are scheduled to release the Hubble on Wednesday from the shuttle’s cargo bay, where it has been anchored since last week.
Discovery is scheduled to return to Florida on Friday.