"We're excited to be a part of the Everest Expedition," said Charlie Trimble, president of the company that bears his name. "The work being done on the mountain can help us understand more about the world around us, how it changes and how the body works. This information can be applied to everyday life. The science on the mountain above 29,000 feet will have value to those of use who live at sea level."

American Wally Berg, a mountain guide from Boulder, Colo., and Apa Sherpa reached the summit at 9 a.m. on May 20. Base camp reported that the weather was so clear that Berg spent two hours on Mt. Everest's summit at 29,028 feet-fulfilling the expedition's science mission of securing a GPS receiver on the summit of the world's tallest mountain. Now GPS data is being collected at four points along the mountain-Kala Pattar, Base Camp, the South Col and Summit-to precisely track the slow geological movements of the mountain over time.

The 1998 Everest Extreme Expedition, organized by geographer Brad Washburn of the Boston Museum of Science, consisted of an expert team of climbers, doctors, and scientists for the Massachusetts Institute of Technology (MIT) and Yale University. The scientific mission placed geological equipment and GPS surveying receivers on the mountain to measure the peak and to conduct experiments in physiology and tele-medicine to determine how the extreme altitudes affects the climbers bodies. The task -- measuring both man and mountain -- is as challenging as the mountain itself. The climbers endured climactic extremes that can torture the body and impair the mind.

Temperatures on Everest can drop as low as -45 degrees Celsius, so cold that plastics become brittle and batteries stop working. The altitude is more conducive to jetliners than mountain climbers. The thin air pressure causes laptop computers to crash. It can also kill a human with no acclimatization in a matter of hours. Mental capacity is also reduced.

In this hostile environment, both man and machine must perform to perfection. Unlike Sir Edmund Hillary's first ascent in 1953, today's climbers use complex space-age technology that must be both highly reliable yet easy-to-use. Among the tools: Trimble GPS receivers not only helped to survey the mountain, but also assisted scientists monitor the medical effects of the climbers as they ascend the mountain.

The four Americans climbing Everest were fitted with bio-paks recording how their bodies reaction to the environment. That information, coupled with positioning data from Trimble's Lassen GPS receivers, provided researchers at the base camp with the most detailed information ever compiled on the effects of altitude and climbing. From there, the information was either logged or transmitted by satellite phone to an earthstation in California and transmitted to MIT for further analysis. It is the ultimate in tele-medicine.

"We're trying to piece together new instrumentation to record a richer picture of the mountain and the people on it," said Michael Hawley of MIT, which is teaming with Yale University to compile research on the ascent. "The data should tell us a lot about the nature of the body in such an extreme environment. No one has looked at this before."

Despite Everest's notoriety, no one knows the mountain's precise height. The accepted elevation of 29,028 feet includes the icecap, but can vary by as much as 20 feet depending on the season. In addition, movement of the earth's crust -- a geologic bump and grind -- is raising the Nepal Himalayas up to a centimeter a year. But scientists also wonder whether erosion is negating an overall increase.

The climbers attached weather probes and Trimble 4800 receivers at various points along the summit, providing position and altitude information to within a fraction of an inch. Repeat observations of these stations in the future will allow scientists to determine the true, bedrock height of Everest and monitor the rate of movement.

Despite the climatic extremes, the Trimble equipment is strictly off-the-shelf, the same as the receivers typically used by surveyors and civil engineers in friendlier climates. It is simple and easy-to-use, important factors when altitude befuddles brains and when bodies are seemingly mummified in bulky protective clothing.

The severe climate and unexpected quirks leave little room for error. But the biological and geological data obtained from the climb is expected to benefit even those who never get closer to Everest than a newspaper photo.

"So far, medicine has focused on fixing you when something breaks," said MIT's Hawley. "This is about finding out how the body works all day. It will become as simple as strapping on a wristwatch and creating a day-to-day medical chart. That's where we are headed. By targeting Everest we have a great propellant for the technology and then over the next few years we will bring it home so Mother can use it."