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Eventful 15-Day Mission for Shuttle Discovery Ends
CAPE CANAVERAL, Fla., Nov. 7 — The shuttle Discovery glided to a safe landing here Wednesday, bringing to a close an eventful mission that combined challenging space station construction and emergency repairs.
The shuttle flew over North America from the northwest to the southeast and touched down on the 15,000-foot landing strip at the Kennedy Space Center shortly after 1 p.m. It could be seen passing high above the landing site as a speedy white dot, its distinctive double sonic ba-BOOM sounding moments after it passed overhead, having traveled more than 6.2 million miles since it roared off the launching pad on Oct. 23.
The mission started out as a pivotal moment in construction of the International Space Station, tightly packed with goals that included delivering a new room — the Harmony module — and relocating an enormous solar array and truss from its temporary position atop the station to its permanent location on the left side.
Moving the 35,000-pound array required two spacewalks and a nimble handoff between the robotic arms of the shuttle and the station. Along with those spacewalks and one to prepare the Harmony’s external fittings, the mission also called for a fourth spacewalk in which astronauts would test repair techniques for the shuttle’s delicate thermal tiles, and a fifth to begin preparing the station for the December visit of the shuttle Atlantis.
The first three spacewalks went smoothly, and the truss was moved successfully. But two problems caused mission managers to change their plans for the remainder of the mission.
The first was a problem with a rotary joint that keeps the right-side arrays facing the sun. Engineers had noticed that the joint was vibrating oddly and using too much power; during the second spacewalk, on Oct. 28, Daniel M. Tani removed a cover from the joint and found that it was fouled with metal shavings, suggesting that some part of the joint was grinding itself down. The joint will be repaired next year.
Then on Oct. 30, as astronauts inside the station opened the newly relocated solar array, a guide wire snagged on one of the folding panels’ hinges and tore two holes in a 110-foot-long “wing” of the array. Plans for the remaining spacewalks were shelved to take on a high-stakes, high-risk effort to repair the torn array.
On Saturday, Scott E. Parazynski rode the station robotic arm, extended with a sensor boom from the shuttle, to reach the array, snip the errant wires and apply five “cufflinks” that took the strain off of the material around the tears and allowed the damaged array to be fully extended.
The shuttle’s seven astronauts were Pamela A. Melroy, the commander, who is a retired colonel in the Air Force; the pilot, Col. George D. Zamka of the Marine Corps; Dr. Parazynski; Stephanie D. Wilson; Col. Douglas H. Wheelock of the Army; Paolo A. Nespoli, an Italian representing the European Space Agency; and Mr. Tani, who flew up with the crew and remained aboard the station. The shuttle brought Clayton C. Anderson back to Earth on his 15th wedding anniversary; he had lived and worked aboard the station since June.
In interviews from space on Tuesday, Mr. Anderson said he expected that readjustment to gravity might be a little rough.
In an evening news conference, Ms. Melroy said the mission felt like hitting “a triple home run” with its dual construction tasks and the round-the-clock effort to come up with a fix for the solar array. “What you saw is who we are at NASA,” she said.
The end of this mission sets off a scramble aboard the space station to prepare for the next shuttle visit, with three spacewalks planned by the three-member station crew so that the orbiting outpost would be ready for a new laboratory module, known as Columbus, that will be brought up by the Atlantis on a mission that may begin as early as Dec. 6.
In a news conference after the landing, NASA’s administrator, Michael Griffin, said it was hard for most people to appreciate the difficulty and the accomplishments of the work going on in orbit far above their heads.
“I think — and I don’t say this lightly — I think that building the space station is far more difficult and certainly far more complex than was executing Apollo,” Mr. Griffin said. “What’s happening here is extraordinary. And it’s way beyond anything that has ever been done by human beings before, anywhere.”
Difficulties like the solar array problem are to be expected, he said, but can’t be predicted.
“I can’t change the brake pads on my car without encountering any problems,” Mr. Griffin said. “Part of learning how to live and work in space is learning how to identify and deal with those problems when they do occur.”
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