The question How many of these six military "orbital threat" techniques have been demonstrated in a (more or less) publicly recognized way? begins:

If you are having a good day then under no circumstances should you read the US Defense Intelligence Agency's Challenges to Security in Space1 (Information cutoff date, January 2019) linked in Axios' The rise of military space powers

and one of the six is "Chemical Sprayers".

Question: I'm just curious, has a spacecraft ever actually sprayed a chemical (or anything) on to another spacecraft intentionally for any reason at all? If so, what was sprayed, and why?

From page 10:

Orbital Threats

Orbital Threats: Orbital or space-based systems are satellites that can deliver temporary or permanent effects against other spacecraft. These systems could include payloads such as kinetic kill vehicles, radiofrequency jammers, lasers, chemical sprayers, high-power microwaves, and robotic mechanisms. Some of these systems, such as robotic technology for satellite servicing and repair and debris removal, have peaceful uses but can also be used for military purposes.

1and also don't read Space Threat Assessment 2020

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    $\begingroup$ Innocent-me only can imagine nitrogen (or air) being sprayed onto an astronomical device to clean a mirror from dust. $\endgroup$
    – B--rian
    May 25, 2021 at 7:38
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    $\begingroup$ @B--rian I'm going to start a company and launch a fleet of ion-propelled cubesats that go around spraying and cleaning lenses and windows of spacecraft cameras and optical sensors. I'm going to be rich! I'm going to become a billionaire and start a space tourism company and wear a blue jumpsuit and make my own astronaut wings and everything! $\endgroup$
    – uhoh
    Aug 7, 2021 at 9:15
  • $\begingroup$ @blobbymcblobby it looks like you are quoting a source which is (presumably, hopefully) not secret. Consider posting as an answer unless it's a secret! $\endgroup$
    – uhoh
    Jan 16, 2022 at 3:11
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    $\begingroup$ ah, no demonstrable information to say it happened or was tested, especially given the age. Given I've noticed NASA and other such papers on Chinese websites I rather think that they've looked at these too.. $\endgroup$ Jan 16, 2022 at 3:21

1 Answer 1


Clickbait header:

The Russians sprayed chemicals from Mir onto the Space Shuttle!!

However, it was all coordinated up front.

Jet exhaust from the Mir space station thrusters were deliberately impinged on a plate mounted on the shuttle's robot arm.

DTO 829 - Plume Impingement and Contamination

The primary objective of this was to record data on a plate mounted on the RMS during the firing of the Mir 13-kg thrusters. Additional data were collected during primary RCS thruster firings after a cold-soak to aid in expanding the data base. These data have been given to the sponsor and an evaluation of the data will be reported in separate documentation.

enter image description here

Data gained from this experiment was critical in the development of the bipropellant plume contamination model for the Russian 130 N engine, which is used extensively on the Russian segment of the ISS, as well as all the Progress and Soyuz vehicles.



  • DTO - Developmental Test Objective
  • RCS - Reaction Control System
  • RMS - Remote Manipulator System (robot arm)

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