Discovery crew makes final check-up before pivotal spacewalk

May 29, 1999
Web posted at: 11:20 p.m. EDT (0320 GMT)

In this story: Dangerous mission Hitched to a robot arm Dozens of spacewalks ahead RELATED STORIES, SITES

HOUST0N (CNN) -- Two astronauts from the space shuttle Discovery made another historic leap late Saturday, when they stepped out into space to begin work on the International Space Station.

Astronaut Tamara Jernigan entered the vacuum of space roughly 240 miles above Earth shortly after 11 p.m. EDT, followed by Dan Barry, in a spacewalk expected to last six hours.

They will attach a crane and other equipment to the station, the first of two tons' worth of supplies that will be transferred during Discovery's mission.

Several months from now -- in March -- the first residents are expected to move into the new station.

Dangerous mission

Spacewalks generally are considered the most dangerous part of any mission after launch and landing. Among the procedures completed by Jernigan and Barry on Saturday were final checks of their emergency rescue equipment.

The spacewalk follows by a day Discovery's historic docking with the new station. Jernigan and Barry will hang out bags of tools for future spacewalkers, among other tasks.

The spacewalkers spent part of Saturday checking tools they will use and reviewing spacewalk procedures. They also rested up for the big space adventure.

Hitched to a robot arm

International Space Station

The two spacewalkers will work with Ellen Ochoa, who will be inside the shuttle operating Discovery's robot arm, and with Canada's Julie Payette, who will coordinate the effort from the aft flight deck.

"Tammy Jernigan will be fixed to a portable foot restraint at the end of the shuttle's robot arm, like a telephone repair worker on the end of a cherry picker," said NASA spokesman Rob Navias.

Jernigan and Barry will maneuver two cranes from the Discovery's payload bay to locations outside the space station. The cranes will be used in future space station construction.

Mission STS-96 is the first construction-related flight in six months.

Dozens of spacewalks ahead

NASA has another 42 spacewalks scheduled for the assembly phase of the $60 billion science outpost. Completion is targeted for 2005.

On space station missions there is the added danger of an astronaut becoming untethered from the shuttle and drifting away. With the shuttle docked to the space station, rescue would be difficult.

Orbital tests on the emergency propulsion units carried by spacewalking astronauts have yet to be completed.

"As a matter of fact, in training we started talking about that scenario," Mission Commander Kent Rominger said in a preflight interview.

"It's not a very pleasant one to talk about, but we do have a (robot) arm and maybe you can get to them with the arm."

The crew of five Americans, one Canadian and one Russian aboard Discovery docked with the space station in the early hours of Saturday and will pull away on June 3. The shuttle is scheduled to return to Earth on June 6.

Next March, the first crew to live aboard the space station is scheduled to arrive on a Russian Soyuz spacecraft.

Reuters contributed to this report.

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