Thursday, April 08, 2010

NASA expects one-day extension for Discovery mission

Discovery and its crew of seven are likely to stay docked on the International Space Station for an extra day because of its failed high-speed data transmission antenna.

Without it, it's safer for the shuttle crew to conduct a pre-landing heat shield inspection while still docked at the space station.

The mission was planned to last 13 days but like most missions had a an extra day available in case conditions warranted, called a plus-one day.

"The team is working on a plan that would include in all likelihood adding a day, the plus-one day, to the mission, to accommodate the ability to do that late inspection at the end of the docked mission," said LeRoy Cain, deputy shuttle program manager.

He said a final decision could come when the Mission Management Team meets Friday. With a one-day extension, Discovery would be expected to land April 19, the day before a United Launch Alliance Atlas V rocket is scheduled to blast off with an Air Force payload from Cape Canaveral.

That launch would likely slip one day to give the Eastern Range time to turn around from the shuttle landing to the rocket launch.

Discovery's Ku-band antenna problem has put managers about a half-day behind analyzing imagery from the first heat shield inspection, performed Tuesday on the mission's second day.

So far, Cain said it does not appear that a more detailed, or "focused," inspection will be necessary this week. However, some parts of Discovery's port wing remained to be analyzed.

In addition to the late inspection, Cain said managers as a precaution want to stow the Ku-band antenna while the orbiter is docked, to be sure there are no problems closing the payload bay doors on the flight home.

If for some reason it didn't stow properly -- a problem not expected to arise -- a spacewalk could be required to manually return it to a landing position.

Discovery's crew is sleeping until 8:51 p.m. Upon awaking for Flight Day 5, they'll begin preparations for the mission's first of three planned spacewalks by Rick Mastracchio and Clay Anderson.


Anonymous said...

If the Atlas is already a day after landing (now April 20), why would an added day to the mission push the launch to the 21?

James Dean said...

The Eastern Range needs more than a day to transition its assets from the shuttle landing to the Atlas launch. So ULA agreed to schedule its launch two days after the shuttle landing -- on the 20th based on the shuttle's original plan to land on the 18th. If a shuttle mission extension moves its landing to the 19th, the Atlas launch would move to the right a day, to the 21st.