Spacelab, the laboratory portion of the space shuttle, will be equipped with sophisticated scientific equipment. The scientists aboard will monitor experiments designed by 13 teams of scientists, including one designed by Prinz and Bartoe's team at the Naval Research Lab.

The experiments will investigate the sun and the earth's land and sea environments and storm systems. More than 200 teams applied for a place for their experiments aboard Spacelab 2.

"It's like flying a brick," said Prinz of the 75-ton shuttle, described as the workhorse of the next phase of the space age. "This thing can't come down in the ocean." The Enterprise, which will orbit the earth 150 miles above the earth's surface, will be launched like a rocket and will land like an airplane at Kennedy Space Center in Florida.

A joint venture between NASA and the European Space Agency, four shuttle vehicles are being built by the European Space Agency at a projected cost of at least $7 billion. Each vehicle is expected to be launched as many as 50 times.

Prinz and Bartoe will not wear space suits because the craft is pressurized. Suits will be on board in the event of an emergency.

Living quarters for the six crew members will be a cramped 12 by 15 feet. "There's going to be a traffic problem in there," said Bartoe, laughing. "I guess there'll also be heavy use of Right Guard."

In preparation for their mission Prinz and Bartoe will spend the next few years criss-crossing the country from Cambridge to Cal Tech, meeting with teams of scientists whose experiments they will carry out. They will also make frequent trips to Marshall Space Flight Center in Huntsville, Ala., and to Johnson Space Center in Houston for training.

The selection of Prinz and Bartoe was preceded by months of applications, interviews and preliminary physical exams. On March 10 scientists were flown to Houston for NASA's rigorous week-long physical exam. "They tested literally every joint in our bodies," Prinz recalled.

"All of us were apprehensive that they'd pick up something we didn't even know we had," recalled the 33-year-old Bartoe. During the treadmill test, when Bartoe's blood pressure broke 200, one of the team doctors who had been closely monitoring him turned to his colleagues and, with great satisfaction said, "Ah! He's totally exhausted."

Besides the psychiatric exam (eight of the 10 said they wantd to be reincarnated as some variety of bird), there was the personal rescue sphere test, designed to weed out claustrophobics and stimulate an emergency transfer from one craft to another.

"It's like being inside a basketball," Bartoe said. Candidates are zipped into a small plastic bag, which is then pressurized. "They told us we would be in there for an indeterminate amount of time, but it turned out to be only 15 minutes. One man called it the world's smallest smelly gymnasium."