Antenna failure hampers astronauts’ survey of space shuttle Discovery, laser images delayed

Antenna failure hampers crew’s shuttle inspection

CAPE CANAVERAL, Fla. — Discovery’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.

Without the antenna, the seven astronauts have no way to send or receive big packages of information, like the images of the shuttle’s wings and nose that are usually sent immediately to Mission Control.

Instead, commander Alan Poindexter and his crew had to store the data on 40-minute tapes that were fed, in turn, into a computer for digital conversion. In all, six tapes were filled, containing 35 to 40 gigabytes of information. All that information will be relayed once the shuttle reached the International Space Station on Wednesday morning, 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 25 miles out. But it still was not working early Wednesday, and NASA gave up on it for the 215-mile-high docking.

Mission Control said the astronauts would rely on other navigation 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.

Flight director Richard Jones said the main effect is the one-day delay in getting the results from Tuesday’s survey, as well as data collected aboard Discovery during liftoff.

“The experts who look at that data and process that data and turn that data upside down, left and right … they’re very good at that,” Jones said. “I’m confident that once they get that data, it’s going to look and feel like a normal mission at that time.”

It will take about four hours to transmit all the survey data, using space station resources.

Despite the extra work, the astronauts took just 20 minutes longer than usual to complete the normally five-hour survey. Jones characterized the problem as an inconvenience. “Gosh, we’re successfully working around it,” he told reporters.

The astronauts noticed some discoloration on the right wing while scanning it with the 100-foot, laser-tipped inspection boom. But Jones said that was not 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.

In addition, a thermal tile appeared to break loose from the shuttle tail 42 seconds after liftoff. The loss occurred in an area that sees little heat during re-entry — the trailing edge of the speed brake panel — and therefore was expected to be a “non-issue,” said LeRoy Cain, chairman of the mission management team. Tiles are there essentially to protect against the heat of launch.

The laser images collected Tuesday — along with zoom-in shuttle pictures taken by the station crew just before Wednesday’s docking — 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 malfunction of a shuttle’s KU-band antenna, a 3-foot dish on a 7-foot-long assembly located in the payload bay. It happened in 2000 during a station construction mission. But this particular breakdown has engineers stumped. Discovery’s antenna can move, pointing toward NASA communication satellites, but is essentially nonfunctional in every other way.

The antenna likely will remain unusable for the rest of the 13-day flight. For the second night in a row Tuesday, Mission Control had to read aloud to the astronauts all the changes to their work schedule. More important, a second shuttle survey, normally carried out right after undocking, likely will take place while Discovery is still attached to the space station.

With no news packages being transmitted to Discovery because of the breakdown, Poindexter called Mission Control on Tuesday morning to ask about the NCAA championship game the night before. When informed Duke beat Butler 61-59 in the final seconds, the commander said: “Ah man, that sounds like a great game.”

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.

On the Net:

NASA: www.nasa.gov/mission_pages/shuttle/main/index.html