Columbia's payload is filled with the Spacehab module and the Freestar cross-bay bridge. Photo: NASA-KSC

"We'll be doing a complicated set of breathing maneuvers," Clark said. "There are eight different experiments with dozens of investigators, primarily from Europe, and they're looking at the changes in the oxygen exchange in your lungs as the blood flow changes with different body positions.

"They're looking specifically at the changes in respiratory or lung function when patients have to be on their backs for extended periods of time. In fact, there's some good evidence that patients in intensive care units would be better off on their stomachs as opposed to their backs.

"This entails a huge amount of overhead to take care of them that way but certainly if there's much better oxygen exchange and lung function, then it's worth that overhead," Clark said. "They've been studying us in different positions, on our stomachs and on our backs, studying the air exchange."

For Brown, bone loss experiments could provide insights into problems affecting millions on Earth.

"That's something that's a problem for everybody when we get older, particularly women," he said. "It turns out astronauts, when we go to space and no longer have the stress of gravity on our skeletons, we lose calcium and so we're going to be studied for that.

"We're actually a very good model, a very accelerated model, for what happens to people over many, many, many years. So it's useful to study us to learn more about how to slow or prevent osteoporosis here on Earth. ... We also have quite a few locker experiments that have bone cells in them, again, to study the same metabolism and why bone cells either gain or lose calcium."

Chawla highlighted a zeolite crystal growth experiment that could help pave the way for efficient fuel cells.

"We carry precursor solutions in tubes that we mix on orbit," she said. "And once the solutions are mixed, we put these tubes in a furnace and let the crystals grow. Zeolites are materials that have lots of holes in them much like a sponge, but they attract materials of unique capacities towards them, unique characteristics.

"The applications are very wide ranging and very interesting," she said. "One of them is to come up with dyes that hold better to the paper. Another one is these days we are talking about coming up with alternate fuels like hydrogen as opposed to gasoline combustion. And it's hard to store hydrogen at room temperatures. You have to basically compress it and then it becomes a hazardous thing to deal with.

"One of the experiments that a (researcher) is doing on this flight is to come up with a material that can have hydrogen embedded in the zeolite material so you can store it at room temperatures."

Another suite of six experiments was provided by students in six countries as part of an education program managed by Space Media, a Spacehab subsidiary.

In one, students in Australia will study how weightlessness affects the webs of garden orb weaver spiders. A Chinese experiment study how the lack of gravity affects the development of silkworms and a Japanese project will do the same with Medaka fish. A school in Liechtenstein is studying the tunneling behavior of carpenter bees and students at a high school in New York will study how weightlessness affects a small colony of ants.

Three technology demonstration experiments are mounted on the roof of the RDM, exposed to the space environment. Another six experiment packages, known collectively by the acronym FREESTAR, are mounted on a truss just behind the RDM in Columbia's cargo bay.

One FREESTAR experiment is devoted to studying the behavior of xenon at low temperatures, another will characterize Earth's ozone layer and a third will measure the amount of solar radiation reaching Earth, part of an ongoing study to chart the value of the solar constant.

"One of the experiments I'm working on is called SOLSE, shuttle-ozone limb sounding experiment, and it's to evaluate a new algorithm to measure the ozone levels in an altitude-type profile instead of looking straight down," McCool said. "I think the world as a whole is interested in global warming and the preservation of our ozone layer and this will certainly help in understanding the ozone and its depletion."

The FREESTAR suite also includes a package of 10 student experiments in the Space Experiment Module; an experimental space radio; and the Mediterranean Israeli Dust Experiment, or MEIDEX, featuring a multi-spectral camera designed to measure the distribution and properties of desert dust suspended in the atmosphere over the Mediterranean basin.

MEIDEX also will be used to study strange "transient luminous events," or sprites, that shoot upward toward space from thunderstorm clouds.

Ramon, who will help operate the instrument, said the Israeli experiment marked "a door opening for scientists from both countries to have mutual research and collaboration."

"This is ongoing, actually. A few months ago, there was talk between scientists here in the United States and they were talking about a continuous Meidex experiment, a Meidex 2. The idea was to put a Meidex camera on the station."

A flood of data from the experiments aboard Columbia will be beamed back to Earth in realtime using the shuttle's Ku-band antenna, all but eliminating live television from the orbiter. Only a handful of media interviews, a crew news conference and occasional 10-minute crew-choice video downlinks are currently planned.

Assuming an on-time liftoff, Columbia will return to Earth around 8:49 a.m. on Feb. 1.

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