Bad Weather Clouds Shuttle Liftoff Sunday

Bad weather, which scrambled Columbia’s launch schedule earlier this month, now is threatening to disrupt Challenger’s liftoff on Sunday with schoolteacher Christa McAuliffe in the crew, NASA said today.

Shuttle meteorologists said a weather front was expected to move into the area Sunday, breaking a string of clear days and bringing clouds and a 30% chance of rain.

Similar conditions caused two of Columbia’s record seven launch postponements and forced three landing wave offs here before that shuttle was detoured to land in California.

The National Aeronautics and Space Administration said it is hoping for a break in the weather during a three-hour launch period that begins at 6:36 a.m. PST.

Weather in the form of blowing sand at an emergency landing site in Dakar, Senegal, already has postponed the flight one day. The delay was necessary so that an alternate site, the international airport at Casablanca, Morocco, would be available in daylight in case a problem shortly after liftoff forced the shuttle to cross the Atlantic and land in North Africa.

The meteorologists said the outlook for Dakar on Sunday was poor, while Casablanca appears marginal.

During the flight McAuliffe will teach two lessons which students in hundreds of schools will watch on the Public Broadcasting Service. She also will make a demonstration film to be distributed to schools after the mission.