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(Decom)mission: Possible!

April 14, 2023
Image of the earth with a satellite over it and vintage tape recorder in the background

“This tape will self-destruct in five seconds.”

In the long-running TV show, Mission: Impossible, this familiar refrain ran at the end of every mission message to the agent operatives. The tapes would then automatically self-destruct in a cloud of smoke, ensuring that they would not compromise the missions and cause trouble.

NOAA’s three Polar Operational Environmental Satellites (POES)--NOAA-15, NOAA-18, and NOAA-19–now also have a way to keep themselves out of trouble in space should things go awry. These satellites can decommission themselves if life-ending conditions arise. This feature is called autonomous decommissioning control (ADC), and it was recently added to the POES satellite fleet.

But unlike the dramatic, smoke-filled self-destruction of the Mission: Impossible tapes, the satellites’ decommissioning happens quietly and efficiently within the satellite’s systems and will place the satellite in a safe state to reduce the possibility of breakup of the spacecraft. 

How does it do this? If the ADC software finds a serious issue that will jeopardize the function or control of the satellite and its systems, and total failure of the satellite is imminent, ADC will execute a series of commands to safely decommission the satellite. 

Some of those commands would be to disconnect all battery charge paths, disable all transmitters, deplete nitrogen gas, and place the flight computers into an infinite loop. This would minimize any future potential breakup (or other catastrophic failure) that could add debris to the satellite’s orbit plane, which could compromise the operation of other crucial satellites. 

Normally, a ground-based, human operator would execute decommissioning actions for a satellite. However, the POES operators are able to communicate with each satellite only while it is visible over a ground site–a mere 10 to 15 minutes during the satellite’s full, 101-minute orbit of the Earth. This short window of time might not be sufficient for operators to execute end-of-life commands. Therefore, ADC runs continuously to monitor and execute final decommissioning at any time should fatal conditions arise.

Why was ADC technology developed? In June 2014, the NOAA-16 satellite experienced a severe overvoltage, and its self-correcting backup system failed. Over several months, these events led to harmful unregulated voltage in the satellite’s systems. Unfortunately, the NOAA-16 satellite broke apart 18 months after the initial overvoltage, which created a debris field of over 200 objects. After that event, NOAA and its team of partners uploaded autonomous decommissioning control to the three remaining POES satellites in a flight software patch to reduce the chances that these spacecraft would suffer a similar fate.

Adding ADC functionality to the POES satellites will ensure that they decommission themselves as soon as possible if the systems ever detect a fatal condition. This proactive stewardship ensures that continuing the remote sensing capabilities of older satellites while responsibly safeguarding the space environment is Mission: Possible for NOAA and its partners.