Endeavour Countdown Under Way

The countdown to Endeavour's Friday evening launch officially began at 10 p.m. today.

The first shift of NASA and contractor representatives has manned stations in Firing Room 4 of Kennedy Space Center's Launch Control Center to monitor shuttle systems and launch preparations over the next several days.

NASA has scheduled a pre-launch news conference on Wednesday no earlier than 11 a.m., featuring LeRoy Cain, Mission Management Team chair, Mike Leinbach, shuttle launch director and Kathy Winters, shuttle weather officer.

You can watch the news conference live here at The Flame Trench. Just click the NASA TV image above or at the right side of the page to launch a NASA TV viewer.

With the countdown in progress, NASA officials said crews would begin checkout and configuration of avionics systems that would continue into Wednesday morning.

Also Wednesday, NASA said workers will prepare on-board cryo-reactant tanks used to produce electrical power on orbit, complete preparations to load power reactant storage and distribution system, activate and test navigational systems and complete flight deck preliminary inspections.

A built-in countdown hold is scheduled at 2 p.m., lasting four hours. All but essential personnel will be cleared from launch pad 39A for tests of the shuttle's pyrotechnic initiator controllers.

In a briefing Tuesday morning, NASA Test Director Jeff Spaulding declared shuttle systems to be in "great shape" and said no technical issues were being worked.

Wednesday's news conference should update a Tuesday weather forecast showing a 40 percent chance that clouds and rain showers could delay Friday's launch.

After arriving at Kennedy Space Center just before 4 p.m. Tuesday, Endeavour Commander Chris Ferguson and Pilot Eric Boe practiced landings on the spaceport landing strip in a modified Gulfstream jet.

The seven-person crew later dined with spouses, then settled into their quarters in the Operations and Checkout Building. The astronauts are scheduled to head to the launch pad around 4 p.m. Friday for a 7:55 p.m. liftoff.

IMAGE NOTE: Above, the image at left shows a view of launch pad 39A at Kennedy Space Center, next to live NASA TV footage. Below, in Firing Room 4 of the Launch Control Center, then-Kennedy Space Center Director Jim Kennedy watches one of the computer screens as the countdown heads for launch of Space Shuttle Discovery on mission STS-121. Photo credit: NASA/Kim Shiflett