International Space Station Friday the 13th Power Cut: Fixable in 2016

Summary: An International Space Station Friday the 13th power cut in a solar array wing is fixable in 2016, NASA's Daniel Huot announced Nov. 16.

Friday, Nov. 13, 2015, power cut is in a solar array wing; Earth's horizon and International Space Station (ISS) solar array panels photo by ISS Expedition 17 (April 8, 2008–Oct. 24, 2008) crewmember, Monday, Aug. 4, 2008; NASA ID ISS017-E-012652: Public Domain, via Wikimedia Commons

Friday, Nov. 13, 2015, brought a little bad luck to the International Space Station when a short in the 1B power channel led to a partial loss of power in one of the station’s eight solar array wings at around 18:00 Universal Coordinated Time (UTC).

On Monday, Nov. 16, Daniel Huot, NASA public affairs officer, informed the press that essential devices and systems run by the channel now are redistributed and that Expedition 45’s six-member crew are not in danger. Any on-site repairs by Commander Scott Kelly and his team of five flight engineers will have to wait until 2016 for delivery of electrical equipment via a resupply rocket.

The cargo module of an upcoming shipment by Orbital ATK, scheduled to launch from Cape Canaveral, Florida, on Dec. 3, is already packed for flight. NASA expects to include the repair parts in the cargo slated for delivery early in 2016 by SpaceX, NASA’s other Commercial Orbital Transportation Services (COTS) provider.

As the intended systemic response to an upstream short circuit, the trip in Direct Current Switching Unit 1B serves to protect downstream equipment from damage. Mission Control’s protocol includes cutting the power in the affected channel to prevent power feeds into shorted systems. The station’s overall fault-tolerant design allows redundant systems, such as several Audio Terminal Units and certain command and control computer systems, to power off without impacting essential systems.

Mission Control aims to identify the short’s source by studying the Electrical Power System’s telemetry data, such as individual power circuit currents and thermal signatures. Telemetry data reveals indicators of failures requiring spacewalks for on-site repairs rather than remote recovery by ground commanding by Mission Control. A previous power cut from a short at the station on Friday, April 11, 2014, could not be recovered remotely and necessitated a spacewalk to repair an external Multiplexer/Demultiplexer (MDM), an electronics unit of multiply streamed data.

After regulation at an established setpoint of 160 volts by a Sequential Shunt Unit, the Solar Array Wing’s solar power is directed to the Direct Current Switching Unit for distribution to downstream users. The Direct Current Switching Unit’s six high-powered switches, which trip in overcurrent situations, may be controlled remotely by ground commands from Mission Control.

If the International Space Station Friday the 13th power cut requires a spacewalk, the team, under the command of NASA’s Scott Kelly, will be making repairs as the space station’s 46th expedition, scheduled to run from Dec. 11, 2015, to March 2, 2016.

photo by NASA/ESA: ISS Updates @ISS101, via Twitter Nov. 13, 2015

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Friday, Nov. 13, 2015, power cut is in a solar array wing; Earth's horizon and International Space Station (ISS) solar array panels photo by ISS Expedition 17 (April 8, 2008–Oct. 24, 2008) crewmember, Monday, Aug. 4, 2008; NASA ID ISS017-E-012652: Public Domain, via Wikimedia Commons @ https://commons.wikimedia.orgwiki/File:Earth_horizon_and_International_Space_Station_solar_panel_array_(Expedition_17_crew,_August_2008).jpg

photo by NASA/ESA: ISS Updates @ISS101 via Twitter Nov. 13, 2015, @ https://twitter.com/ISS101/status/665256320556277760

For further information:

Hays, Brooks. "Space station power short circuits, system repairs needed." United Press International > Science News. Nov. 16, 2015.
Available @ http://www.upi.com/Science_News/2015/11/16/Space-station-power-short-circuits-system-repairs-needed/8071447704205/

ISS Updates @ISS101. "Space Station suffers partial Loss of Power, Mission Control evaluates Recovery Options." Twitter. Nov. 13, 2015.
Available @ https://twitter.com/ISS101/status/665256320556277760

NASA Kennedy / KSC @NASAKennedy. ".@OrbitalATK #Cygnus spacecraft is being prepared for the Dec. 3 launch to @Space_Station." Twitter. Nov. 13, 2015.
Available @ https://twitter.com/NASAKennedy/status/665247448684699648

"Space Station suffers partial Loss of Power, Mission Control evaluates Recovery Options." Spaceflight101 > ISS > Expedition 45. Nov. 13, 2015.
Available @ http://spaceflight101.com/iss-expedition-45/space-station-suffers-partial-loss-of-power-mission-control-evaluates-recovery-options/