Tuesday, April 06, 2010

Discovery inspects heat shield, preps for Wednesday approach to ISS

Discovery is mid-way through this morning's heat shield inspection, with no obvious signs so far of worrisome damage incurred during Monday morning's launch from Kennedy Space Center.

Shuttle commander Alan Poindexter reported two "very small areas of interest" on the starboard wing's leading edge. "I don't think they're a big deal, but a little discoloration," he radioed to Mission Control.

The areas were marked on tapes that the Discovery crew downloaded to computer hard drives, data that will be transferred to station computers for routing to analysts on the ground after Discovery arrives early Wednesday.

That time consuming procedure is necessary because the orbiter antenna used to downlink video isn't working.

Still, the crew remains roughly on schedule to complete the survey of heat-shielding tiles and reinforced carbon-carbon surfaces around 6 a.m., nearly 24 hours after launch.

Also at 6 a.m. EDT, NASA will host a mission status briefing that you can watch live here -- click on the NASA TV box at right to launch a video player.

The balky Ku-band antenna also has a radar system that is typically used during the shuttle's approach to the station to help gauge it distance and the rate at which the shuttle is closing in. Engineers aren't certain it won't work, but aren't counting on it.

"Even if it's not, Discovery should still be able to dock without a problem," a NASA TV commentator said. "Between the other backup systems that exist to give the range and range rate information, Discovery should be covered even if the Ku-band antenna doesn't work in that mode."

Rick "C.J." Sturckow, an astronaut communicating with the crew from Houston, ran through a series of rendezvous procedures with commander Alan Poindexter that Poindexter and pilot Jim Dutton will follow in the event the radar capability is unavailable.

"We're not going to chase the radar all day," Sturckow said. "If it's just not working out, then we'll give up on radar early."

He referred to backup procedures "that you've already practiced many times."

"Just a few weeks ago, C.J.," Poindexter responded. "Mash and I will talk about this in detail in the morning and be ready to go with the radar fail procedure if required."

The heat shield inspection using the shuttle's robotic arm and a 50-foot boom extension began around 1 a.m. with a scan of the starboard wing. It moved on to the nose cap around 3:40 a.m., and the port wing is still to come.

It will likely be late in the week before mission managers give the Thermal Protection System preliminary clearance or determine that any areas need a closer look, known as a "focused inspection."

IMAGES: Above, a shot of tiles on Discovery's starboard wing. Credit: NASA TV. Below, Discovery's launch was brilliant as it lifted off launch pad 39A at Kennedy Space Center at 6:21 a.m. EDT April 5. Photo credit: NASA/Ben Cooper


Conor said...

This seems to mean that they won't be able to send the pictures from the heat shield inspection after leaving the ISS back to Earth.
I suppose the station could take a second set of photos after Discovery departs.

James Dean said...

Conor: you're righ. They're considering doing the late inspection before undocking.