Antenna Failure Hampers Shuttle Inspection
April 6, 2010 - 5:00 AMDiscovery's astronauts surveyed their ship Tuesday for signs of launch damage, but the job was complicated by the failure of the space shuttle's big dish antenna.
The antenna failed to operate after Discovery blasted into orbit Monday on a space station supply run. That leaves the seven astronauts with no way to send or receive big packages of information, like the images of the shuttle's wings and nose that were collected early Tuesday morning.
Normally, these pictures are sent immediately to Mission Control in Houston so experts can begin scouring them as soon as possible.
Because of the antenna malfunction, commander Alan Poindexter and his crew had to store the data on 40-minute tapes that were fed, in turn, into a computer. The information will be relayed once the shuttle reaches the International Space Station on Wednesday, delaying analysis.
The rendezvous was expected to be trickier than usual, given the antenna trouble. The antenna is supposed to provide radar tracking as the shuttle approaches the station, from 28 miles out. Engineers had little confidence the system would be working by then.
Mission Control said the astronauts could rely on other tools, and stressed the linkup would not be any more dangerous.
"We're planning on getting there on time," Poindexter assured flight controllers. He said he trained for just such an event, two weeks ago back in Houston.
As the shuttle inspection got under way, the astronauts reported that the on-board images had gone dark, as they adjusted the position of the 100-foot, laser-tipped inspection boom.
"Is there any chance that we're just staring out into black space right now?" Mission Control asked.
"Yep. You nailed it," replied pilot James Dutton Jr.
Poindexter wanted to make sure that "the sheer volume of data" being collected could fit in the computer's hard-drive. Mission Control assured him it would.
The crew kept a sharp eye on the thermal shielding during the survey, so they could make a quick report of anything unusual.
This routine inspection of the wings and nose -- the most vulnerable parts of a shuttle during re-entry -- was put in place following the 2003 Columbia disaster. Columbia was destroyed by a hole in a wing, the result of shedding fuel-tank foam.
An estimated three small pieces of foam came off during Discovery's liftoff, but too late to be of any concern, officials said. The laser images -- along with zoom-in shuttle pictures taken by the station crew Wednesday -- will ascertain whether Discovery was struck by foam or any other launch debris.
At the same time, engineers are poring over launch pictures in search of more lost foam or possible impacts.
This isn't the first time a shuttle's KU-band antenna -- a 3-foot dish on a 7-foot-long assembly -- has malfunctioned. But this particular breakdown has engineers stumped.
It's quite possible that the antenna will remain unusable throughout the 13-day flight. If that's the case, Mission Control will have to read aloud to the astronauts all of the changes to their work schedule, getting each day off to a slow start. That's what happened Monday night.
The first of three spacewalks planned for this graveyard-shift mission -- to replace an old ammonia tank at the space station -- remains set for Friday.
The space station is nearly complete. Only three shuttle flights remain after this one.
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