Fwd: Computer Glitch May Require Spacewalk Fix, Delay Cargo Ship Launch

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From: "Gary Johnson" <gjohnson144@comcast.net>
Date: April 13, 2014 6:29:29 PM CDT
To: "Gary Johnson" <gjohnson144@comcast.net>
Subject: FW: Computer Glitch May Require Spacewalk Fix, Delay Cargo Ship Launch

 

NASA press release

 

Back Up Computer Not Responding to Commands

April 11, 2014

 

The Mission Control team at NASA's Johnson Space Center in Houston confirmed Friday night that a backup computer on the exterior of the International Space Station (ISS) called a Multiplexer-Demultiplexer (MDM) is not responding to commands. The station's MDM computers control some systems associated with robotics aboard the space station. The primary MDM operating aboard the space station is functioning normally and there is no immediate impact to space station operations. The computer outage does not pose a risk to the six crew members aboard the space station. ISS teams are assessing next steps to attempt to bring the computer back online or replace it. Replacing the backup MDM, if needed, would require a spacewalk. The backup MDM would provide redundancy for robotic systems that will be needed to attach the SpaceX Dragon spacecraft currently scheduled to launch on Monday and rendezvous with the ISS on Wednesday. NASA is continuing to work toward a Monday launch of the SpaceX cargo resupply mission pending further evaluations by the ISS Program. The latest information will be available here at www.nasa.gov/station.

 

The six-member Expedition 39 crew was off-duty Friday in recognition of Cosmonautics Day. Russian President Vladimir Putin called the International Space Station to congratulate the crew the day before Cosmonautics Day, April 12, the anniversary of the historic first human spaceflight by Yuri Gagarin.

 

The station is set for an orbital reboost Saturday morning when the ISS Progress 53 resupply craft, docked to the Zvezda service module, will fire its thrusters for 13 minutes, 32 seconds. This will put the orbital lab at the correct altitude for a crew swap in May.

 

Expedition 38/39 crew members Mikhail Tyurin, Koichi Wakata and Rick Mastracchio will return to Earth May 14 inside the Soyuz TMA-11M spacecraft. They will be replaced May 29 when the Expedition 40/41 crew of Maxim Suraev, Reid Wiseman and Alexander Gerst arrive inside the Soyuz TMA-13M spacecraft.

 

Another cargo ship is set for a launch to the space station on Monday at 4:48 p.m. EDT. The Dragon commercial cargo craft will liftoff atop a Falcon 9 rocket on the SpaceX-3 mission from Cape Canaveral Air Force Station, Fla.

 

The third Dragon capsule to visit the station will deliver about 5,000 pounds of gear and return 3,500 pounds of cargo, including science results for analysis, to Earth. When Dragon is captured and berthed to the Harmony node, there will be five space vehicles parked to the international space laboratory.

 

 

                       

NASA mulls 'black box' failure aboard space station

 

NASA studies glitch with backup ISS robotics computer

04/11/2014 10:49 PM 

By WILLIAM HARWOOD

CBS News

 

A computer "black box" in the International Space Station's solar power truss that provides redundancy for robotic arm operations stopped responding to commands Friday, NASA said in a statement. If the component cannot be coaxed back to normal operation, the planned Monday launch of a SpaceX Dragon supply ship -- which must be captured by the station's robot arm -- could be delayed.

 

The avionics box, known as a multiplexer-demultiplexer, or MDM, is mounted in the central S0 section of the station's power truss. Spares are available, but a spacewalk would be required to install a replacement, assuming flight controllers at the Johnson Space Center in Houston are unable to resolve the problem remotely.

 

"The mission control team at NASA's Johnson Space Center in Houston confirmed Friday night that a backup computer on the exterior of the International Space Station called a multiplexer-demultiplexer is not responding to commands," NASA said in a brief statement.

 

"The station's MDM computers control some systems associated with robotics aboard the space station. The primary MDM operating aboard the space station is functioning normally and there is no immediate impact to space station operations. The computer outage does not pose a risk to the six crew members aboard the space station."

 

Flight controllers are studying what might be needed to restore the unit to normal operation or what might be required to replace it if recovery efforts are not successful.

 

"Replacing the backup MDM, if needed, would require a spacewalk," the NASA statement said.

 

The apparent failure occurred Friday afternoon, amid work at the Cape Canaveral Air Force Station to prepare a commercial SpaceX Dragon cargo ship for launch to the space station atop a Falcon 9 rocket. Liftoff is targeted for 4:58 p.m. Monday and if all goes well, the uncrewed supply ship will reach the lab complex around 7:11 a.m. Wednesday.

 

But unlike supply ships built by the Russians and the European Space Agency, the Dragon is not able to dock on its own. Instead, the station's robot arm, operated by astronauts inside the space station, is used to lock onto a grapple fixture so the capsule can be moved into position for berthing at the Earth-facing port of the forward Harmony module.

 

While the Canadian-built robot arm remains fully functional, the loss of redundancy due to the apparent MDM failure could prompt NASA mission managers to consider a launch delay for the SpaceX/Dragon mission if the MDM cannot be restored to normal operation. But pending additional troubleshooting, the SpaceX launch remains on track for Monday, with forecasters predicting a 70 percent chance of acceptable weather.

 

"The backup MDM would provide redundancy for robotic systems that will be needed to attach the SpaceX Dragon spacecraft currently scheduled to launch on Monday and rendezvous with the ISS on Wednesday," NASA said in its statement. "NASA is continuing to work toward a Monday launch of the SpaceX cargo resupply mission pending further evaluations by the ISS Program."

 

The SpaceX cargo craft is loaded with 4,600 pounds of equipment and supplies, including spacesuit components intended to prevent any recurrence of a potentially catastrophic helmet water leak that occurred during a spacewalk last year.

 

If a spacewalk is required to replace the suspect MDM, two station astronauts, presumably Rick Mastracchio and Koichi Wakata, would use spacesuits currently aboard the station, following safety procedures implemented for two excursions last December to replace a faulty cooling system component.

 

Those spacewalks were successful, and there was no recurrence of the leak that occurred during a July 2013 spacewalk by European Space Agency astronaut Luca Parmitano.

 

© 2011 William Harwood/CBS News Contact Me

 

 

Space Station Computer Glitch May Require Spacewalk Fix, Delay Cargo Ship Launch

By Tariq Malik, Managing Editor   |   April 12, 2014 07:11am ET

 

NASA is studying a glitch with a backup computer on the International Space Station, an issue that could potentially force astronauts to perform a spacewalk repair and delay the planned Monday launch of a SpaceX cargo ship.

 

Space station officials announced the glitch late Friday (April 11) after confirming that a backup computer on the space station's exterior was not responding to commands. The computer, known in NASA parlance as a Multiplexer-Demultiplexer, is a backup controller for some robotics systems on the space station.

 

"The computer outage does not pose a risk to the six crew members aboard the space station," NASA officials wrote in a statement. "ISS [International Space Station] teams are assessing next steps to attempt to bring the computer back online or replace it."

 

Any plan to replace the backup computer would require a spacewalk by astronauts, NASA officials added. Meanwhile, the primary computer in the affected system is working normally.

 

The glitch comes three days ahead of the planned launch of a Dragon cargo ship by the private spaceflight company SpaceX on Monday (April 14). The Dragon spacecraft is due to launch from Cape Canaveral Air Force Station in Florida atop a Falcon 9 rocket. It is packed with nearly 5,000 lbs. (2,268 kilograms) of supplies for the station's crew, but can only be captured by the space station's robotic arm.

 

"The backup [computer] would provide redundancy for robotic systems that will be needed to attach the SpaceX Dragon spacecraft currently scheduled to launch on Monday and rendezvous with the ISS on Wednesday," NASA officials wrote in a statement. "NASA is continuing to work toward a Monday launch.

 

SpaceX's Dragon launch has already been delayed nearly a month due to unrelated damage to a ground-based tracking radar system used by the Florida launch site that has since been repaired.

 

SpaceX has a $1.6 billion contract with NASA to provide 12 unmanned cargo delivery missions to the International Space Station using its Dragon spacecraft and Falcon 9 rockets. Monday's planned launch will be the SpaceX's third Dragon delivery mission for NASA since 2012.

 

Another company, the Dulles, Va.-based Orbital Sciences Corp., has a $1.9 billion contract with NASA for eight cargo missions using its own unmanned Antares rockets and Cygnus spacecraft. The first official Cygnus cargo mission launched in January, with the next one slated for June.

 

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