3 ms·

How are docking spacecraft handled, which likely have a different base charge?

ceejayoz 2y ago
Venting xenon plasma. (Also important for not frying astronauts on spacewalks.) https://en.wikipedia.org/wiki/Plasma_contactor https://en.wikipedia.org/wiki/Plasma_contactor
RandomThoughts3 2y ago
Protective actions are required by the docking standard so it’s taken care of at docking but I find it very hard to find detailed information about implementations. It’s either very niche or considered sensitive enough to not be published widely. I guess they use the same solution than during EVA which is running the Plasma Contactor Units to dissipate any buildup.
- schiffern 2y ago
  The docking spacecraft must follow a NASA standard[1] to avoid building up electrostatic charge. From the Commercial Crew requirements document[2]: 3.9.3.13 Integrated Space Vehicle Electrostatic Charge Control 3.9.3.13.1 LEO Charging Design Standard The spacecraft shall meet the intent of the requirements contained in NASA-STD-4005, Low Earth Orbit Spacecraft Charging Design Standard. [R.CTS.285] How the contractors achieve that might be proprietary. It looks like (at one time) SpaceX used electrically conductive paint[3] as part of their mitigations. [1] https://standards.nasa.gov/standard/NASA/NASA-STD-4005 https://standards.nasa.gov/standard/NASA/NASA-STD-4005 [2] https://ntrs.nasa.gov/api/citations/20150010757/downloads/20150010757.pdf https://ntrs.nasa.gov/api/citations/20150010757/downloads/20... [3] https://phys.org/news/2013-03-white-coating-spacex-dragon-trunk.html https://phys.org/news/2013-03-white-coating-spacex-dragon-tr...
  - RandomThoughts3 2y ago
    You missed this one: "International Docking System Standard (IDSS)" [0] which I actually read that before answering hence my "required by the docking standard". You will see that it says: "IDSS compliant mechanisms protect against electrostatic discharge through the soft capture system" which is to say not much. That’s still more than the previous standard for which the paragraph on ESD just says "RESERVED". [0] https://ntrs.nasa.gov/api/citations/20170001546/downloads/20170001546.pdf https://ntrs.nasa.gov/api/citations/20170001546/downloads/20...
deleted 2y ago
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Venting xenon plasma. (Also important for not frying astronauts on spacewalks.) https://en.wikipedia.org/wiki/Plasma_contactor https://en.wikipedia.org/wiki/Plasma_contactor

RandomThoughts3 2y ago

Protective actions are required by the docking standard so it’s taken care of at docking but I find it very hard to find detailed information about implementations. It’s either very niche or considered sensitive enough to not be published widely. I guess they use the same solution than during EVA which is running the Plasma Contactor Units to dissipate any buildup.

schiffern 2y ago
The docking spacecraft must follow a NASA standard[1] to avoid building up electrostatic charge. From the Commercial Crew requirements document[2]: 3.9.3.13 Integrated Space Vehicle Electrostatic Charge Control 3.9.3.13.1 LEO Charging Design Standard The spacecraft shall meet the intent of the requirements contained in NASA-STD-4005, Low Earth Orbit Spacecraft Charging Design Standard. [R.CTS.285] How the contractors achieve that might be proprietary. It looks like (at one time) SpaceX used electrically conductive paint[3] as part of their mitigations. [1] https://standards.nasa.gov/standard/NASA/NASA-STD-4005 https://standards.nasa.gov/standard/NASA/NASA-STD-4005 [2] https://ntrs.nasa.gov/api/citations/20150010757/downloads/20150010757.pdf https://ntrs.nasa.gov/api/citations/20150010757/downloads/20... [3] https://phys.org/news/2013-03-white-coating-spacex-dragon-trunk.html https://phys.org/news/2013-03-white-coating-spacex-dragon-tr...
- RandomThoughts3 2y ago
  You missed this one: "International Docking System Standard (IDSS)" [0] which I actually read that before answering hence my "required by the docking standard". You will see that it says: "IDSS compliant mechanisms protect against electrostatic discharge through the soft capture system" which is to say not much. That’s still more than the previous standard for which the paragraph on ESD just says "RESERVED". [0] https://ntrs.nasa.gov/api/citations/20170001546/downloads/20170001546.pdf https://ntrs.nasa.gov/api/citations/20170001546/downloads/20...

deleted 2y ago

[deleted]