NASA confirms command error temporarily felled TESS planet hunter
(2026/01/27)
- Reference: 1769511494
- News link: https://www.theregister.co.uk/2026/01/27/nasa_tess_error/
- Source link:
NASA has confirmed that its planet hunter, TESS (Transiting Exoplanet Survey Satellite), entered safe mode due to a command error that inadvertently left the spacecraft's solar arrays angled away from the Sun.
[1]TESS was recovered days after entering safe mode due to discharged batteries. This was caused by the vehicle's solar panels being pointed away from the Sun, which meant the batteries could not charge sufficiently. The incident was the result of a command transmitted from the ground.
The plan was to slew TESS to point at a target. When it entered safe mode, TESS was conducting a week-long observation of comet 3I/ATLAS.
[2]
A NASA spokesperson told The Register that there were no guardrails in place to prevent this scenario, although there were protections to prevent the spacecraft's batteries from draining completely. It is likely these kicked in and sent the spacecraft into safe mode, from which it could be recovered.
[3]
[4]
A spacecraft's safe mode shuts down all but the most essential systems, usually maintains attitude control, and awaits instructions from controllers. It is designed to protect the vehicle.
A spokesperson at the space agency added: "The mission is reviewing and updating procedures to prevent this command error from happening in the future."
[5]NASA planet hunter resumes operations after low power incident
[6]NASA's Artemis II Moon rocket arrives at the launch pad
[7]Congress throws NASA a lifeline, leaves Mars sample mission to die in the dust
[8]ISS stint ends early as NASA aborts Crew-11 over crew illness
In many ways, TESS was lucky. There are plenty of examples of spacecraft being left borked after a command from Earth had unintended consequences. The [9]Viking 1 Mars lander , for example, ended its mission in 1982 after a faulty command from Earth terminated communications, and attempts to regain contact proved unsuccessful.
There is also the Solar and Heliospheric Observatory (SOHO) probe, a joint NASA-ESA project. In 1998, a step was skipped in a routine calibration procedure, effectively disabling the spacecraft's normal safe mode and triggering a catastrophic series of events that left the spacecraft [10]tumbling in space . It was only through some impressive engineering teamwork and persistence that SOHO was located and eventually recovered.
[11]
Fortunately, TESS's safe mode worked as designed and kept the spacecraft in a state where engineers could restore it after realizing that something had not gone to plan.
However, it will be interesting to see how a command that resulted in a borked spacecraft was sent up in the first place, and how NASA's boffins plan to ensure this doesn't happen again. ®
Get our [12]Tech Resources
[1] https://www.theregister.com/2026/01/23/nasa_planet_hunter_resumes_operations/
[2] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2aXia1xDWmm5mFOdf0fzNCAAAA48&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[3] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aXia1xDWmm5mFOdf0fzNCAAAA48&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[4] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33aXia1xDWmm5mFOdf0fzNCAAAA48&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[5] https://www.theregister.com/2026/01/23/nasa_planet_hunter_resumes_operations/
[6] https://www.theregister.com/2026/01/19/nasa_artemis_ii/
[7] https://www.theregister.com/2026/01/16/nasa_science_budget/
[8] https://www.theregister.com/2026/01/12/iss_command_handover/
[9] https://science.nasa.gov/mission/viking-1/
[10] https://www.theregister.com/2020/07/29/esa_soho_space_extenders/
[11] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aXia1xDWmm5mFOdf0fzNCAAAA48&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[12] https://whitepapers.theregister.com/
[1]TESS was recovered days after entering safe mode due to discharged batteries. This was caused by the vehicle's solar panels being pointed away from the Sun, which meant the batteries could not charge sufficiently. The incident was the result of a command transmitted from the ground.
The plan was to slew TESS to point at a target. When it entered safe mode, TESS was conducting a week-long observation of comet 3I/ATLAS.
[2]
A NASA spokesperson told The Register that there were no guardrails in place to prevent this scenario, although there were protections to prevent the spacecraft's batteries from draining completely. It is likely these kicked in and sent the spacecraft into safe mode, from which it could be recovered.
[3]
[4]
A spacecraft's safe mode shuts down all but the most essential systems, usually maintains attitude control, and awaits instructions from controllers. It is designed to protect the vehicle.
A spokesperson at the space agency added: "The mission is reviewing and updating procedures to prevent this command error from happening in the future."
[5]NASA planet hunter resumes operations after low power incident
[6]NASA's Artemis II Moon rocket arrives at the launch pad
[7]Congress throws NASA a lifeline, leaves Mars sample mission to die in the dust
[8]ISS stint ends early as NASA aborts Crew-11 over crew illness
In many ways, TESS was lucky. There are plenty of examples of spacecraft being left borked after a command from Earth had unintended consequences. The [9]Viking 1 Mars lander , for example, ended its mission in 1982 after a faulty command from Earth terminated communications, and attempts to regain contact proved unsuccessful.
There is also the Solar and Heliospheric Observatory (SOHO) probe, a joint NASA-ESA project. In 1998, a step was skipped in a routine calibration procedure, effectively disabling the spacecraft's normal safe mode and triggering a catastrophic series of events that left the spacecraft [10]tumbling in space . It was only through some impressive engineering teamwork and persistence that SOHO was located and eventually recovered.
[11]
Fortunately, TESS's safe mode worked as designed and kept the spacecraft in a state where engineers could restore it after realizing that something had not gone to plan.
However, it will be interesting to see how a command that resulted in a borked spacecraft was sent up in the first place, and how NASA's boffins plan to ensure this doesn't happen again. ®
Get our [12]Tech Resources
[1] https://www.theregister.com/2026/01/23/nasa_planet_hunter_resumes_operations/
[2] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2aXia1xDWmm5mFOdf0fzNCAAAA48&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[3] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aXia1xDWmm5mFOdf0fzNCAAAA48&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[4] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33aXia1xDWmm5mFOdf0fzNCAAAA48&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[5] https://www.theregister.com/2026/01/23/nasa_planet_hunter_resumes_operations/
[6] https://www.theregister.com/2026/01/19/nasa_artemis_ii/
[7] https://www.theregister.com/2026/01/16/nasa_science_budget/
[8] https://www.theregister.com/2026/01/12/iss_command_handover/
[9] https://science.nasa.gov/mission/viking-1/
[10] https://www.theregister.com/2020/07/29/esa_soho_space_extenders/
[11] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aXia1xDWmm5mFOdf0fzNCAAAA48&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[12] https://whitepapers.theregister.com/