John Herrington prepares return to Mother Earth

The space shuttle Endeavour undocked from the International Space Station on Monday, ending a successful week of space station assembly tasks and crew exchange activities. John Herrington is on his way back to Earth, but it may take a couple of tries. Landing is planned for Wednesday, December 4th, at 3:48 p.m. EST at the Kennedy Space Center, but thunderstorms are forecast which would violate the weather rules.

When the shuttle fires its engines for de-orbit it must land about an hour later ? there's no waiting for the weather to improve. In an incredibly drastic case if there was a major disaster at the Kennedy Space Center's 15,000-foot long runway, like another plane crashing on the middle of the runway, the shuttle could be diverted to a nearby airport ? most likely Orlando International Airport.

The concept of a space shuttle returning from space landing at a commercial airport with terminal buildings filled with tourists coming to Florida to see Disneyworld is rather bizarre, but an actual part of NASA's contingency plans.

Because the de-orbit burn takes place half a world away the weather forecasters have to be fairly conservative in their predictions. An unexpected shower would make the landing more difficult for the pilots and could damage the shuttle's delicate thermal protection system which would result in costly repairs before the next shuttle flight.

Commander Jim Wetherbee will occupy Endeavour's left hand seat. He's the most experienced shuttle commander with five previous flights, four of them as the commander. He will become the only astronaut to land the shuttle five times. Pilot Paul Lockhart will occupy the right seat. He's on his second flight after serving as the pilot on Endeavour's previous mission, STS-111 in June.

John Herrington will occupy the center seat, sitting behind the two pilots. As the flight engineer he will monitor the shuttle's systems and keep the crew on the timeline.

The other seat on the flight deck will be empty. Instead of sitting upstairs with the shuttle crew, Mike Lopez-Alegria will sit downstairs with the returning Expedition 5 long duration crew, Valeri Korzun, Peggy Whitson, and Sergei Treschev. He's there to assist them after landing. Having Lopez-Alegria downstairs makes the job more difficult for the orbiter crew, especially Herrington.

Before the mission Herrington said: "On entry I have to do the role of two people, both Mike [Lopez-Alegria] and myself. And that can be a real challenge, with both of the pilot and commander working malfunctions I have to stay on the nominal timeline as well as make sure they complete their procedures. It takes a real good understanding of what they're working on, where they're at so I can back them up."

There is a bizarre ritual astronauts go through before returning from space. In weightlessness the blood in your body moves around and tends to concentrate in the torso. In an effort to push more fluids into the arms and legs astronauts are required to drink over a quart of salty liquid a couple of hours before landing. If there's a wave-off then they drink more liquid.

And yes, the body does have to get rid of the excess liquid. After one mission was waved off several times the flight surgeons "awarded" the crew the silver kidney award for all of the times they had to fluid load. In Herrington's case he's chosen lemon-orange drink with salt tablets.

Herrington's mission may set a new record for fluid loading. The weather forecast doesn't improve until Friday. Before the shuttle undocked from the space station mission control warned the shuttle not to give away all of their excess food to the space station crew since there was a strong possibility the mission would have to get extended due to bad weather in Florida.

If the weather remains bad in Florida for several days and the forecasts remain bad, shuttle entry flight director Wayne Hale would be forced to send Endeavour to the backup landing site at Edwards Air Force Base in California.

For Herrington, the biggest difference will be a delay until he gets to see his family. But for the shuttle program there's a minimum hit of a week to the schedule, and a cross-country trip on the back of NASA's specially modified 747 shuttle carrier aircraft.