The crew of the shuttle Endeavour strapped in today at pad 39A for a dress-rehearsal countdown that sets the stage for launch March 11 on a 16-day space station assembly mission featuring five spacewalks, installation of a Japanese logistics module and assembly of a complex hand-like attachment for the lab's robot arm.

Credit: NASA

Shuttle commander Dominic Gorie, pilot Gregory Johnson, flight engineer Michael Foreman, Richard Linnehan, Robert Behnken, Japanese astronaut Takao Doi and space station flight engineer Garrett Reisman boarded Endeavour early today and worked through the final hours of a terminal countdown demonstration test, or TCDT, that ended with the simulated ignition and shutdown of the ship's main engines.

The astronauts hope to strap in for real the night of March 10 for a launch at 2:28:10 a.m. on March 11. As it now stands, NASA will have two shots at getting Endeavour off the ground, on March 11 or 12, before standing down a few days to make way for the already planned launch of an unmanned Delta 2 rocket carrying an Air Force Global Positioning System satellite.

Endeavour's planned launching comes just three weeks after the shuttle Atlantis landed at the Florida spaceport to close out the first of six missions planned for 2008.

"We're really excited to be here during this dry count practice run for launch here in a couple of weeks," Gorie told reporters Sunday. "The Kennedy Space Center is running at a pretty fast pace as you can imagine with two launches like this back to back. They've got a great thing going, we're going to keep it going with Endeavour's launch here on March 11. Endeavour's in great shape and is ready for us to go."

Bill Gerstenmaier, head of space operations at NASA headquarters, will chair a two-day flight readiness review Thursday and Friday. Assuming no problems develop, NASA plans to start Endeavour's countdown at 3 a.m. EST on March 8 (note: the United States switches to daylight savings time (GMT-4 hours) at 2 a.m. on March 9).

As usual with space station missions, the shuttle can take off roughly five minutes to either side of the moment Earth's rotation carries the launch pad into the plane of the lab's orbit. NASA typically targets the middle of the window, known as the "in-plane" time, a strategy that improves performance but effectively reduces the launch window to just five minutes.

Here are the latest launch windows for the STS-123 mission (in EDT; dates refer to the "in-plane" launch times; launch day is flight day 1; flight day 4 dockings are possible on even dates through March 22):

DATE/GMT...WINDOW OPEN...IN-PLANE......WINDOW CLOSE..DOCKING

03/11/08...02:23:10 AM...02:28:10 AM...02:33:10 AM...Flight day 3

03/12/08...01:57:23 AM...02:02:23 AM...02:07:23 AM...FD-3

03/13/08...01:34:51 AM...01:39:51 AM...01:44:51 AM...FD-3

03/14/08...01:09:09 AM...01:14:09 AM...01:19:08 AM...FD-3

03/15/08...12:46:36 AM...12:51:36 AM...12:56:36 AM...FD-3

03/16/08...12:20:54 AM...12:25:54 AM...12:30:53 AM...FD-3

03/17/08...11:58:22 PM...12:03:22 AM...12:08:22 AM...FD-3

03/17/08...11:32:39 PM...11:37:39 PM...11:42:38 PM...FD-3

03/18/08...11:10:08 PM...11:15:08 PM...11:16:43 PM...FD-3

03/19/08...10:44:24 PM...10:49:24 PM...10:54:24 PM...FD-3

03/20/08...10:21:53 PM...10:21:53 PM...10:24:32 AM...FD-3

03/21/08...09:56:10 PM...10:01:10 PM...10:06:09 PM...FD-3

03/22/08...09:33:39 PM...09:38:39 PM...09:43:39 PM...FD-4

03/23/08...09:07:55 PM...09:12:55 PM...09:17:55 PM...FD-3

The primary goals of mission STS-123 are to deliver Japan's pressurized logistics module; to install a sophisticated Canadian robotic manipulator for the station's main robot arm; to test a new heat-shield repair technique; to ferry Reisman to the station to join the Expedition 16 crew; and to bring European Space Agency astronaut Leopold Eyharts back to Earth after six weeks in orbit.

The Japanese module will be temporarily attached to the upper port of the forward multi-hatch Harmony connecting module. During a shuttle flight in late May, the much larger Kibo laboratory module will be mounted on Harmony's left-side port and the logistics module carried aloft aboard Endeavour will be moved to an upper hatch on the far end of the new lab.

Assuming an on-time launch, Gorie will guide Endeavour to a docking with the space station around 11:27 p.m. on March 12. The Japanese logistics module will be installed the next day during the first of five planned spacewalks. Linnehan and Reisman will carry out the first excursion, Linnehan will be joined by Foreman for the second on March 15 and by Behnken for the third on March 17. All three EVAs will be devoted primarily to assembling the new Canadian special purpose dexterous manipulator, or DEXTRE, a mechanical hand of sorts that can be attached to the station's robot arm.

Benkhen and Foreman will carry out the final two spacewalks on March 20 and 22 to test a heat shield repair tool and to help mount the shuttle's heat shield inspection boom on the station. The 50-foot-long boom will be left behind when Endeavour departs because of interference issues when the large Kibo module is launched on the next assembly mission.

If all goes well, Endeavour will undock from the space station around 8 p.m. on March 24 and land back at the Kennedy Space Center around 8:35 p.m. on March 26.