Space station computer outage may force unscheduled spacewalk

This May 23, 2011 photo released by NASA shows the International Space Station at an altitude of approximately 220 miles above the Earth, taken by Expedition 27 crew member Paolo Nespoli from the Soyuz TMA-20 following its undocking. 

A computer outage at the International Space Station may require an EVA (spacewalk) by astronauts and threatens to delay next week's launch of a commercial supply ship for NASA. 

NASA said Friday night April 11, 2014 that a backup computer on the outside of the orbiting lab is not responding to commands. 

Credit: AP Photo /NASA, Paolo Nespoli

A computer outage at the International Space Station may require a spacewalk by astronauts and threatens to delay next week's launch of a commercial supply ship for NASA.

NASA said Friday night that a backup computer on the outside of the orbiting lab is not responding to commands.

The main computer, called an MDM or multiplexer-demultiplexer, is working fine, and the six-man crew is in no danger, officials said.

But these computers control some robotic functions that would be needed for the upcoming supply run by SpaceX, one of two U.S. companies contracted by NASA to keep the space station well stocked. A backup computer would need to be operating for redundancy of those robotic systems.

SpaceX is supposed to launch the unmanned Dragon capsule on Monday from Cape Canaveral.

It contains nearly 5,000 pounds (2267.99 kilograms)of supplies and science experiments.

The mission is already a month late because of extra prep time needed by the California company and unrelated damage to an Air Force radar-tracking device needed for rocket launches.

ESA Astronaut Paolo Nespoli, Expedition 27 flight engineer, works with the Light Microscopy Module (LMM) in the Destiny laboratory of the International Space Station.

Late Friday, Mission Control was trying to determine whether the computer can be repaired or must be replaced.

A replacement would have to be accomplished by spacewalking astronauts.

NASA is still aiming for a Monday launch by SpaceX. But that could change, depending on the status of the bad computer.

Astronauts use the space station's big robot arm to grab onto the Dragon capsule and attach it to the outpost.

The space station is currently home to two Americans, one Japanese and three Russians.

NASA is paying Space Exploration Technologies Corp. (SpaceX) and the Virginia-based Orbital Sciences Corp. to make space station deliveries.

Russia Progress spacecraft, Japan (JAXA) HTV spacecraft, and in Europe ESA's ATV cargo spacecraft also conduct regular supply runs.

Orbital Science Corporation Antares rocket raised into position

This NASA handout photo shows the Orbital Science Corporation Antares rocket seen as it is raised into position at launch Pad-0A, on December 16, 2013, at NASA's Wallops Flight Facility, Wallops Island, Virginia

With the space station cooling system hobbled and a commercial cargo launch waiting in the wings, NASA Tuesday prepared all options but said no decision had yet been made on whether spacewalk repairs would be needed.

Instead, Orbital Sciences rolled its Antares rocket out to the launch pad at Wallops Island, Virginia in preparation for a Thursday launch of its Cygnus supply ship at 9:19 pm (0219 GMT).

Meanwhile, NASA television showed images of astronauts preparing their white spacesuits in case they are called upon to step outside the space station and repair the broken equipment cooling system.

A US space agency spokesman told reporters a final decision could come later Tuesday or early Wednesday.

On Wednesday of last week, NASA learned that a broken valve had interfered with the cooling loops that regulate the equipment temperature aboard the space station.

The six-man crew was never in danger due to the problem, NASA said.

If the agency decides the manuevers it has made from the ground to orchestrate a temporary fix—by manipulating valves and shutting down some equipment—are stable, the Orbital launch could go ahead.

Orbital Sciences' privately owned cargo ship would then start its journey on its first regular commercial mission to supply the orbiting outpost Thursday, berthing at the space station on Sunday at 4:52 am (0952 GMT).

The company did a demonstration launch and berthing at the ISS in September, showing it was capable of the mission and paving the way for more supply trips.

When NASA lost its capacity to reach space with the retirement of the 30-year shuttle program in 2011, Orbital and SpaceX stepped in to fill the void with their privately made, unmanned supply spacecraft.

Both companies have lucrative contracts with the US space agency to ferry supplies to the ISS.