Countdown for Shuttle Launch Begins; Weather Seen Favorable

The countdown began Saturday for the launching of the space shuttle Discovery and the $1.5-billion Hubble Space Telescope, the observatory astronomers hope will solve some basic mysteries of space and time.

The countdown for Tuesday’s liftoff began on time, at 3 p.m., an hour after the five astronauts arrived from Houston’s Johnson Space Center.

Air Force spokesman Ken Warren said that forecasters expected a 90% chance of favorable weather for Tuesday, with a 10% chance of strong surface winds that could force a delay.

The astronauts are expected to deploy the telescope on the second day of the five-day mission. It is the most expensive unmanned spacecraft ever built by the National Aeronautics and Space Administration and has endured seven years of delay because of technical problems and the 1986 Challenger explosion.

The space agency finished charging the telescope’s nickel-hydrogen batteries Saturday afternoon. Technicians then began a final sweep of the shuttle’s payload bay, removing the battery chargers and any remaining protective coverings. The payload bay doors were to be closed early today.

Technicians also repaired a shuttle engine cable and replaced a damaged connector that was found late Friday.

NASA has up to six hours to launch Discovery starting from 5:47 a.m. PDT Tuesday.

ABC, CBS, NBC and the Cable News Network plan to air the launching live. The three broadcast networks will begin coverage during their morning news programs.

The telescope, once deployed, is to orbit 380 miles above Earth for 15 years. It will be capable of detecting objects 50 times fainter and with 10 times greater clarity than the best ground-based observatory.