Space Shuttles

Space shuttle Discovery returned home Friday after landing in California on Oct. 24. After 13 days in space, during which the crew worked on the international space station Alpha and made a record-breaking four spacewalks, Discovery was diverted to Edwards Air Force Base because of bad weather in Florida. High winds over Edwards in the Mojave Desert and a balky bolt on a cover protecting the shuttle's main engines delayed mounting Discovery on its 747 carrier aircraft.

NASA officials tried Monday to explain mysterious oxygen readings aboard the shuttle Discovery as the countdown clocks ticked toward the spaceship's blastoff on a mission to upgrade the Hubble Space Telescope. Officials said they were confident that higher-than-usual oxygen concentrations in Discovery's fuselage would not delay the planned 12:55 a.m. PST launch today.

A weakening electric generator on the space shuttle Columbia could force its astronauts to cut short their 16-day science mission and return to Earth as early as Monday. The generator, called a fuel cell, had been losing voltage since Friday's liftoff, maybe even before, NASA mission operations director Jeff Bantle said Saturday. If the loss continued at a rapid enough rate, the seven astronauts would have to turn off that fuel cell and land, he said.

NASA's countdown clocks started ticking toward a test-firing of the space shuttle Endeavour's three main engines, which will be fired for 22 seconds Monday. If all goes well, launch teams at the Kennedy Space Center in Florida will begin preparing the shuttle for a satellite rescue mission in early May. The engine test is required of all new shuttles.

The National Aeronautics and Space Administration counted down toward a fifth attempt to launch the space shuttle Atlantis early this morning, as clouds and high, gusting winds threatened to delay the launch a fifth time. "It will be nip and tuck," said Air Force Capt. Tom Strange, the shuttle weather officer. "We have to hope for a letup, but at this point we don't see it." As the planned launch time of 12:55 a.m. EST approached, launch director Bob Sieck called for an extended hold.

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.

Technicians on Friday sealed a leaky fuel line to a steering engine compartment of the space shuttle Discovery, taking another step toward launching in late September or early October, NASA officials said. Working in cramped quarters in the shuttle's up-ended cargo bay, engineers first bolted a clamshell-shaped device onto a line found to be leaking nitrogen tetroxide gas more than a month ago.

America's space program hasn't soared this high in nearly 30 years. With John Glenn circling the planet aboard the shuttle Discovery, public enthusiasm over the 77-year-old astronaut's historic flight has NASA officials nearly in orbit themselves. "Nobody expected the magnitude of the public interest and press coverage we got," Joe Rothenberg, chief of NASA's office of spaceflight, said of last week's launch.

What had been a flawless maiden voyage for space shuttle Endeavour ran into serious trouble Sunday as astronauts attempting to snag a stranded $150-million communications satellite sent it spinning out of control. "We've got to get away from this thing," Endeavour commander Daniel C. Brandenstein, 49, said after the first of four rescue attempts pushed the Intelsat 6 satellite into an uncontrollable, 52-degree wobble.