Live at NASA: Crew Aims For Calif. Return

The Endeavour astronauts are preparing for a late-afternoon atmospheric reentry and landing at Edwards Air Force Base in California, and the weather looks as if it will be near-perfect for a scheduled 4:25 p.m. EST touchdown.

Veteran astronaut Pam Melroy is piloting a Gulfstream II aircraft in clear, crystal blue skies over the Mojave Desert military base, flying weather reconnaissance in advance of a go/no-go decision that will come about 20 minutes ahead of a planned 3:19 p.m. deorbit burn.

Endeavour mission commander Chris Ferguson and pilot Eric Boe are preparing to climb into their partial-pressure launch-and-entry garments, and the rest of the crew then will then follow suit.

Also on board are mission specialists Heidemarie Stefanyshyn-Piper, Stephen Bowen, Don Pettit, Shane Kimbrough. NASA astronaut Gregory Chamitoff, who will be returning to Earth after six months in space, is lying on a recumbent seat on the shuttle's mid-deck -- a precaution meant to help ease his reintroduction to gravity.

The astronauts are preparing to start "fluid-loading." Each will be drinking about eight ounces of saline-laced water to counteract the drop of body fluids they'll experience when the reenter a normal gravity field.

Body fluids pool in the head and upper torso in the weightless space environment. But once the shuttle plunges below about 400,000 feet, the astronauts will feel the first tugs of normal gravity in more than two weeks. Body fluids then will be pulled down into the lower torso, circumstances that could cause lightheadedness.

Melroy, meanwhile, is flying through a cloudless sky and light winds -- near-perfect conditions for landing.

Her Shuttle Training Aircraft is a Gulfstream II that has been modified to mimic the shuttle's brick-like dive toward the runway -- one which is seven times steeper than that of a commercial airliner.

Endeavour is scheduled to land on Runway 04, which at 12,000 feet in length is about 3,000 feet shorter than the landing strip at Kennedy Space Center or recently refurbished Runway 22 at Edwards. At 200 feet in width, it is 100 feet narrower than the KSC strip or Runway 22.

NASA has yet to move landing aides and other equipment back to Runway 22, so the plan is to land on the asphalt-concrete Runway 04. NASA is holding open the option of switching to Runway 22 if weather conditions change significantly in the hours leading up to landing.

You can check out this cool interactive graphic of a shuttle landing here: Shuttle Landing

And here's another showing how the shuttle will be brought back to KSC from California: Shuttle Piggyback.

Both are by Florida Today graphic artist Dennis Lowe.