CAPE CANAVERAL — The shuttle Challenger leaves today on a $175 million science mission devoted entirely to West Germany, a landmark cooperative venture that may help NASA realize its dream of building an international space station.
A crew of eight, the largest ever to travel in space, was set for a noon launch. The remnants of Hurricane Juan may bring rain to Kennedy Space Center, but an Air Force forecaster predicted that liftoff would be possible during the three-hour launch window.
Tucked in Challenger's cargo bay is Spacelab, where most of the 76 experiments planned for the mission will be done. Crew members will work around the clock in zero gravity studying spacesickness, plant growth, fluid movement and crystal growth.
While Challenger orbits the Earth for a week, West Germans at a payload control center near Munich will oversee the scientific work. It is the first time another country has managed an entire shuttle payload.
The mission is called Spacelab D-1 -- the D stands for Deutschland. A second West German Spacelab mission is planned for 1988 or 1989.
''The steps from Spacelab with its individual missions to a permanent space station are quite logical,'' said Hans-Hilger Haunschild, deputy secretary of research and technology for West Germany's research ministry.
''By the mid-1990s, a permanently available space station will open up a greatly expanded range of chances for experimentation.''
The United States has asked countries worldwide to contribute to NASA's proposed $8 billion station.
In response, West Germany and other members of the European Space Agency are considering supplying a laboratory and a storage module that would be attached to the station, Haunschild said Tuesday.
Challenger and its payload were reported to be in good shape Tuesday as the countdown progressed. Some biological samples were to be loaded at the last minute Tuesday night.
The scientists who designed the experiments, mostly Europeans and a few Americans, are excited about the potential results of a mission that has been 10 years in the planning.
Most of the experiments involve materials processing. They include the growth of very pure crystals that could improve electronics, and studies that could help the development of lighter, stronger metals.
Other materials processing studies will examine the movements of liquids in weightlessness. The results could have many applications, including spacecraft fuel tank design and processing of semiconductors.
However, crew members will spend up to 70 percent of their time doing life sciences experiments in biology, botany and medicine.
The most elaborate involves a sled on a 12-foot track that runs down the middle of Spacelab. It will be used to test how the human balance system in the inner ear responds to weightlessness.
The inner ear, which needs gravity to function normally, is believed to play a role in spacesickness, a malady that makes about half the astronauts nauseous during their first few days in space.
Researching a solution may be more uncomfortable than the problem itself.
Crew members will be strapped to a chair in several positions.
The chair will move along the track at one-fifth the force of gravity.
In another test, astronauts will wear a helmet that flashes lights in their eyes. At other times their ear canals will be doused with warm or cold water to see how their balance systems are affected.
The responses will be carefully monitored and compared with similar studies aboard the first Spacelab mission in November 1983. The goal is to find a cure for spacesickness and help scientists predict who is prone to it.
Other life sciences experiments include the growth of garden cress plants, corn, and lentils in weightlessness to compare with the same plants grown simultaneously on Earth. This will help scientists learn more about the role gravity plays in plant growth.
In addition, lymphocyte cells, algae cells and other living materials will be grown in weightlessness and compared with those grown on earth for possible applications to space medicine and other biological research.
Challenger's crew is as international as its payload. The five Americans are Henry Hartsfield, commander; Steven Nagel, pilot; and mission specialists Bonnie Dunbar, Guion Bluford and James Buchli. The three European payload specialists are West Germans Ernst Messerschmid and Reinhard Furrer and Wubbo Ockels of the Netherlands.
The shuttle is set to land at Edwards Air Force Base in California Nov. 6 at 12:40 p.m. During the landing, Hartsfield will test a new method of nose- wheel steering that is supposed to lessen brake wear.
If the test works, shuttle landings will resume at Kennedy Space Center in December.