ISS Computer Malfunction Will Require Spacewalk To Fix, Could Delay SpaceX Launch

redOrbit Staff & Wire Reports – Your Universe Online

NASA has announced that a backup computer system onboard the International Space Station will need to be replaced during a spacewalk, and the ongoing problems with the robotic systems could force a previously scheduled SpaceX cargo mission to be postponed, various media outlets reported Saturday.

According to the Associated Press (AP), the US space agency has not yet set a date for the extra-vehicular activity (EVA) required to fix the technical issues impacting some of the space station’s robotic systems. They confirmed that the primary computer is fine and the crew is not in any danger, but noted that Monday’s resupply mission could be delayed.

“Mission managers agreed on Saturday that a spacewalk was needed to replace the bad computer. But officials want one more day before deciding whether the situation is safe enough in orbit to proceed with Monday’s SpaceX launch as planned,” the AP said. “NASA said it would decide on Sunday whether to delay the delivery mission.”

Officials at the US space agency said that preparations for the launch of the SpaceX Dragon cargo craft, currently scheduled for 4:58pm EDT on Monday, would continue – in spite of the Friday failure of the backup computer component affecting the Mobile Transporter rail car on the station’s truss.

In order to discuss the situation, NASA has rescheduled a Sunday morning prelaunch briefing. That briefing will now take place noon EDT at the Kennedy Space Center in Florida.

The SpaceX cargo ship contains about 4,600 pounds of supplies and equipment, including the legs for Robonaut 2 and various scientific experiments, according to Alan Boyle of NBC News.

The component at the heart of the current problem is known as a multiplexer demultiplexer (MDM), and according to NASA, it is one of over a dozen located on the station’s truss which routes computer commands to several different systems on the ISS. The failure Friday was due to a box called EXT-2, which is a backup unit to a prime component on the S0 truss. It occurred during a routine check to make sure that the device was in good condition.

“A reboost of the station using the ISS Progress 53 thrusters was conducted Saturday as planned and placed the laboratory at the correct altitude for Soyuz crew landing and launch operations in May,” the space agency said in a statement. “Station program officials, flight controllers and teams of engineers are working to determine whether there is any risk to launching the SpaceX cargo craft Monday.”

If the launch is allowed to proceed, the Dragon capsule would arrive at the orbital laboratory on Wednesday, where it would be grappled and berthed to the Earth-facing port of the Harmony module. The Canadarm2 robotic arm, which would be used to capture and secure the vehicle, has not been impacted by the failure of the backup MDM.

“While a final decision on the SpaceX launch is being reviewed, another team of engineers is laying out a timeline for a contingency spacewalk that is required to replace the failed spare MDM,” NASA said. “No date for the spacewalk has been scheduled. Such a spacewalk is one of the so-called ‘Big 12’ spacewalks that station crews train to execute for the loss of a critical component on the complex.”