Most experiments will take place in a pressurized laboratory in the payload bay.

Shuttles also served as hosts for more than a dozen physical and biological research missions using a large pressurized laboratory, built by the European Space Agency, which filled the cargo bay.

Two hours after the launching, astronauts activated Spacelab, a 21,840-pound pressurized laboratory carried in the Columbia's cargo bay in which many of the medical experiments will be carried out.

The Discovery is to be launched tomorrow with a crew of seven and a pressurized laboratory in its cargo bay.

Much of the work will be done with 7,500 pounds of research payloads housed in a large pressurized laboratory called the Research Double Module carried in Columbia's cargo bay.

Two teams of astronauts are to operate the pressurized, bus-sized laboratory in shifts around the clock to complete 33 major experiments.

The crew, which includes two medical doctors and a veterinarian, is to do most of its work in a 40-foot-long, European-built pressurized laboratory in the cargo bay.

The six-member crew, including Sergei K. Krikalev, 35, the first Russian astronaut to fly aboard an American shuttle, immediately got to work activating a pressurized laboratory in the cargo bay.

In the cargo bay, the pressurized laboratory, a private, commercial structure called Spacehab that NASA is leasing, contains 13 experiments that focus on developing new drugs and testing new agricultural technology.

Many of the more than 80 experiments aboard the Discovery are housed in a pressurized laboratory in the cargo bay that is connected to the shuttle's crew quarters by a tunnel.