The STS-107 crew patch. Photo: NASA

"We do have a lot of experiments on this flight ... and we're really covering all the major scientific disciplines," said payload commander Anderson. "And each experiment really does have a good application back here on Earth."

But it is a mission that's had a harder time than most getting off the ground.

The flight first showed up on the NASA manifest in September 1999 when launch was scheduled for Nov. 30, 2000. But the mission was delayed six times before a crew could even be named because of shuttle refurbishment and payload changes, including the addition - and subsequent deletion - of former Vice President Al Gore's Triana Earth-watching satellite.

Chawla, Anderson, Brown, Clark and Ramon were named to the flight in September 2000. At that point, launch was targeted for June 2001. By the time Husband and McCool were added to the crew in December 2000, launch had slipped to August 2001. It eventually slipped another year, to July 19, 2002, primarily because of technical problems with the orbiter and delays in space station missions.

Then, a month and a half before launch last summer, the shuttle fleet was grounded because of small but potentially dangerous cracks in fuel line baffles. When all was said and done, Columbia's flight slipped to this month, behind two higher-priority space station missions, STS-112 and STS-113.

"We've made very good use of our time," Husband said of the most recent delay. "Whenever we have these types of launch delays, I would say probably initially there might be a bit of letdown or disappointment, but then we realized we've been given a gift of more time to prepare.

"So we've made really good use of our time. We were able to take some time off, so that was good for us and our families morale-wise, and we were also able to keep our level of proficiency with our training up. So we're doing great now and really looking forward to going to launch. We feel like we're as well trained as we can possibly be."

Columbia's flight is a throwback to pre-station science missions using NASA's now-retired European-built Spacelab modules.

But in this modern incarnation, the bulk of the crew's research will be carried out in a commercially built Spacehab research double module made up of two smaller modules bolted together to make a single two-room laboratory connected to the shuttle's crew cabin by a long tunnel.

Mounted just behind the Spacehab module is a pallet of six more multi-investigation experiment packages that do not require hands-on operation. Still more experiments are mounted on top of the Spacehab module and in the shuttle's crew cabin.

"This mission is fairly unique compared to the shuttle flights we've flown recently in that it is a dedicated science mission," Beck said. "It will span multiple disciplines, such as the life sciences, physical sciences, Earth and space sciences as well as the educational arena. This flight involves multiple NASA centers, the international community and universities and schools throughout the world.

"In the areas of biology and physiology, we'll be conducting several studies to study the effects of weightlessness on crystal growth, plant growth and also the cardiovascular and musculo-skeletal systems. The information we gain from these studies will help develop better drugs, with particular interest in the areas of cancer and osteoporosis research.

"We also have studies of weightless on the human body, which will lead a better understanding of the effects of spaceflight and help us develop better techniques to combat those effects and increase our durations in space," Beck said. "There are studies of combustion and fire suppression processes that will help us potentially lead to cleaner burning techniques here on the ground as well as improved fire suppresion and prevention techniques.

"We have experiments investigating compression of wet sand, which could lead to improved construction techniques, we also will be studying dust storms to gain a better understanding of those effects on weather patterns and to improve our forecasting capabilities.

"We also have experiments to refine the solar constant and the study the Earth's ozone layer. We also have several experiments to demonstrate new technologies, such as water recycling, thermal control, communications and navigation. So that just kind of gives you a flavor of the wide variety of things we'll be doing on this mission."

The research double module, or RDM, is 20 feet long, 14 feet wide and 11 feet high, provides 2,200 cubic feet of pressurized volume and is capable of accommodating up to 9,000 pounds of cargo and experiment hardware. For Columbia's flight, the module is loaded with about 7,500 pounds of experiment gear and supplies. Another 800 pounds of research equipment and samples are mounted in the shuttle middeck area.

Spacehab Inc. builds and outfits such modules for NASA on a commercial basis, primarily for use ferrying hardware and supplies to and from the international space station.

The company's modules have been used for research in the past, but the Spacehab double research module aboard Columbia is the first to be equipped with the support systems needed for space station-class science. Eighteen percent of the research space aboard the RDM aboard Columbia was sold by Spacehab to commercial users around the world while NASA booked the remaining 82 percent.

The NASA experiments require up to 60 percent or more of the mass available in the Spacehab module, 58 percent of the volume and 71 percent of the crew time "largely because of the medical experiments we're undertaking," Charles said.

The module is loaded with nine commercial payloads supporting 21 investigations into bone loss, protein crystal growth, the effects of weightlessness on human physiology and technology demonstrations in space navigation, satellite communications and thermal control systems.

Another four payloads provided by the European Space Agency will support 14 other investigations. And NASA is responsible for a space station risk mitigation experiment, along with 18 payloads sponsored by the office of Biological and Physical Research for 23 investigations.

"I'm really excited," said Clark. "We're doing a huge number of different science experiments in different disciplines. I'm especially excited about the wide range of medical experiments we're doing that will benefit people I know and patients here on Earth."

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