Certainly the first crewed spacecraft had some incandescent light bulbs for indicators, though for cabin illumination the higher efficiency of fluorescent lights was often exploited. The question First use of an incandescent light in an un-crewed spacecraft? covers spacecraft not intended for crew, and touches on the question of non-human occupants.

But here I'd like to simply ask:

Question: When was the last time that an incandescent light bulb was launched into space? Crewed or uncrewed, when was a hot filament launched that was intended to be used to produce light that was used to illuminate something for the purposes of someone or something seeing or imaging it?

This excludes filaments used to warm things by thermal radiation or for thermionic emission of electrons or surface ionization to produce ions, so excludes heaters, electron tubes, mass spectrometers, infrared absorption spectrometers, etc.

The implicit assumption behind there being a "last time" is that it no longer makes sense to use an incandescent light bulb when there are so many more efficient and/or sustainable ways to make solid-state broad-band illuminators for imaging and/or seeing using LEDs and broadband phosphors (i.e. "white light" LEDs).

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    $\begingroup$ Did Starman's Tesla include any form of incandescent lights? $\endgroup$
    – supercat
    Apr 3, 2021 at 18:02
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    $\begingroup$ It's a 2008 Model S. The S's rear license plate was lit by incandescents until 2016, reportedly. Also, its headlights may have been halogens. But I don't think those were ever turned on; neither were cameras aimed at what they'd've lit up. Any other lights in there? $\endgroup$ Apr 3, 2021 at 23:06
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    $\begingroup$ "No one in their right mind" arguments do not stand up to "this part is flight/space qualified, this one is not" arguments :) $\endgroup$ Apr 3, 2021 at 23:52
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    $\begingroup$ @rackandboneman yep, I called attention to the implicit assumption intentionally since I felt it needed to be examined and perhaps counterexamples would be found. $\endgroup$
    – uhoh
    Apr 4, 2021 at 1:49
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    $\begingroup$ @CamilleGoudeseune Starman launched with a Tesla Roadster, not a Model S. The Roadster's final year was 2012 $\endgroup$
    – Adam
    Apr 4, 2021 at 2:02

2 Answers 2


December 2011. At that time, Soyuz TMA-03M flew to ISS. On its successor, TMA-04M, its

SMI-4 light was replaced with a LED headlight.

https://en.wikipedia.org/wiki/Soyuz_MS phrases it:

the old halogen headlights, SMI-4 (СМИ-4), have been replaced with the LED powered headlight SFOK (СФОК).

  • $\begingroup$ fyi I simply haven't been able to get back to this yet but have asked this and it seems I need to start reading. Next challenge is figuring out where to start... And totally unrelated, but you may find interesting this. $\endgroup$
    – uhoh
    Apr 4, 2021 at 21:52

In April 2002, STS-110 delivered some halogen bulbs to ISS.

Ross and Morin ... installed two 40-watt halogen lights on the exterior of Unity and Destiny.

Pages 59-60, "The International Space Station: Building for the Future," John E. Catchpole.

But I wouldn't be surprised if the Soyuz is still using them. Terrestrial aircraft still do!


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