Shuttle set for rare nighttime landing

The Atlantis crew held a news conference on orbit after undocking from Alpha

By Richard Stenger
CNN

(CNN) -- The space shuttle Atlantis crew is scheduled to land in the glare of runway floodlights early Tuesday, having installed a new front door on the international space station during a mission riddled with mishaps.

The $165 million air lock delivered by Atlantis astronauts will allow spacewalking astronauts to venture from space station Alpha without the assistance of visiting shuttles.

NASA said Monday it expects the shuttle will land at the Kennedy Space Center as planned shortly after midnight, despite weeks of drenching rain in nearby sections of Florida.

MORE STORIES Launch a trip to KSC     RESOURCES Message Board   Mission Guide

"The weather forecast looks good," shuttle flight director Wayne Hale told reporters. "The only thing of any note is the possibility the weatherman has of a chance of showers within 30 nautical miles."

The tentative landing time is set for 12:37 a.m. EDT. If rough weather prevents it, the shuttle could try touching down 90 minutes later on its next pass.

Atlantis has enough power and supplies, if necessary, to remain in orbit another three days, during which time the Florida weather is expected to become better.

Alpha's new air lock juts off the side of the space station

NASA hopes to avoid using a backup landing site at Edwards Air Force Base in California because the diversion would cost an estimated $1 million.

The five Atlantis astronauts worked eight days at the orbiting outpost, setting up a 6.5-ton air lock that will permit Alpha crews to venture from the station in U.S. or Russian spacesuits.

Previously, Alpha residents would have had to rely on Russian suits and a much more cramped portal into space.

The air lock construction job was the first in which Alpha's new robotic arm was used. Despite nagging problems during earlier testing, the $600 million crane performed well.

But a flurry of missteps onboard Atlantis and Alpha forced NASA to add another day to the scheduled 11-day mission. A computer crashed. Water spilled. Alarms went off. Air leaked from the air lock. Battery acid appeared to have oozed from a spare spacesuit.

The projected re-entry track for Atlantis

The shuttle visitors were the first to the space station in more than two months. But the Alpha residents should greet their next guests soon. In early August, the shuttle Discovery is expected to bring a fresh crew to the three-story complex and return with the old one.

The Atlantis mission marked a major milestone in space station construction. With the new air lock installed and the 58-foot (17-meter) robotic arm operational, Alpha crews can install station parts that arrive via unmanned cargo ships, without help from shuttle crews.

A project of the United States, Russia, Europe and Japan, the expanding international space station could eventually cost more than $60 billion.