Shuttle Computer OK; Atlantis Cleared for Liftoff

KENNEDY SPACE CENTER, Fla. —  A spare engine computer checked out Saturday and NASA cleared the space shuttle Atlantis for a Tuesday launch with the Jupiter-bound Galileo probe.

Officials said the countdown, interrupted after a previous computer developed a problem, would resume at 9:01 p.m. PDT today, aiming for liftoff during a 26-minute period starting at 9:57 a.m. Tuesday.

The faulty computer, which forced postponement of a planned Thursday launch, was removed and a spare was installed Friday. Testing of the new unit was completed Saturday and workers began closing up the engine compartment, removing work platforms and reinstalling heat shields.

The 230-pound, $6-million computer controls all functions of one of Atlantis’ three main engines during launch. Its failure could lead to an engine shutdown and an emergency landing.

The five astronauts who will fly the mission returned here from their training base in Houston. They had gone back there after the Thursday launch date was scrubbed.

The crew members are commander Donald Williams, pilot Mike McCulley and mission specialists Ellen Baker, Franklin Chang-Diaz and Shannon Lucid.

During the five-day mission, the astronauts are to release the nuclear-powered Galileo spacecraft on the start of a six-year journey to Jupiter. The craft is to shoot a probe into the Jovian atmosphere and orbit the planet, examining it for 22 months.

A federal judge on Tuesday rejected a request by three environmental groups to halt the flight for fear that the Galileo could scatter plutonium, its nuclear fuel, over Florida if the shuttle exploded. The groups have appealed.

A long-range weather forecast said conditions on Tuesday will be 70% favorable. Weather officials said there was a 20% probability of showers or thunderstorms and a 10% chance of winds from the southeast exceeding the launch limit of 23 m.p.h.