Tuesday, April 06, 2010

Discovery inspection complete, but results will be delayed

Seven Discovery astronauts have wrapped up the main event of their first full day in orbit, an inspection of the orbiter heat shields for damage from Monday's launch.

Normally, video from the orbiter's specially equipped boom extension is beamed down to the ground in real time, with the help of a dish-shaped antenna called the Ku-band antenna.

But the antenna hasn't been acting right since being deployed after the crew reached orbit, stymieing Discovery's ability to downlink video or receive e-mail and other data commands from Mission Control.

All should be resolved once Discovery docks with the International Space Station early Wednesday to begin a nine-day stay. Video files can sent down using the station's Ku-band antenna.

But that means it will be at least another day before analysts in Houston can study the images.

The late start doesn't necessarily impact the mission, since a follow up inspection, if deemed necessary, wasn't planned until Flight Day 6, which begins Friday evening.

A "late" inspection typically done after undocking could be done before Discovery leaves. It wasn't immediately clear if that would require additional time for the planned 13-day mission.

Richard Jones, the mission's lead shuttle flight director, said the crew had not reported seeing any serious problems, only a couple of instances of "discoloration" on tiles that Jones said was common.

The next hurdle is docking itself, which could be more challenging than usual because of the same antenna failure. Radar normally used to help track the shuttle's distance and approach speed probably won't be available.

As a result, Discovery will rely more heavily on two star tracking devices in the orbiter's nose.

Jones and the mission controllers and the flight crew were well practiced in backup systems and procedures.

"We plan and train for it," Jones said of the radar failure. "When we were talking to the crew today, they seemed really familiar with it. So both the ground and the crew, we are comfortable where we're at."

NASA has cited several missions that experienced Ku-band antenna glitches, but only one of those was believed to be a problem with the antenna's radar mode -- STS-126 in November 2008, according to a spokesman at Johnson Space Center.

Discovery's crew, led by mission commander Alan Poindexter, is scheduled to go to sleep at 12:21 p.m. and awake at 8:21 p.m. EDT.

The Mission Management Team meets at 2 p.m. and a news briefing will follow at 5 p.m. You can watch it live here by clicking on the NASA TV box at right.

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