Author Topic: Reaction Wheel Assembly Failures - Solved?  (Read 1186 times)

Offline HTAaron

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Reaction Wheel Assembly Failures - Solved?
« on: 06/20/2018 05:09 am »
RWA failures (Kepler, FUSE) discussed on an ancient (2013) thread that I couldn't reply to. Recently, cause traced to (correlated with) electrical discharge resulting from space weather (CME) ...

http://esmats.eu/esmatspapers/pastpapers/pdfs/2017/bialke.pdf
http://esmats.eu/amspapers/pastpapers/pdfs/2018/bialke.pdf

Ceramic bearings offer a possible fix. No info (that I've been able to find) on what the specific ceramic is, though.

Online ccdengr

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Re: Reaction Wheel Assembly Failures - Solved?
« Reply #1 on: 06/20/2018 05:15 am »
I wouldn't say this was solved, it's just another hypothesis. albeit interesting.  From the second paper:

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The scope of this paper is not to present scientifically proven models or conclusions, but only to open the
discussion of anomalous friction signatures to include the effects of electrical discharge...

Offline whitelancer64

Re: Reaction Wheel Assembly Failures - Solved?
« Reply #2 on: 01/08/2019 03:15 pm »
Per this Space News article: https://spacenews.com/scientists-pleased-with-tess-exoplanet-mission/

"The spacecraft’s reaction wheels — which caused problems for another exoplanet mission, Kepler — are based on designs with commercial satellite heritage that should last for decades"

Kepler's reaction wheels were made by Ball Aerospace.

TESS's reaction wheels were made by Honeywell.

Is the manufacturer the reason they are so confident? Or are they a different type of design?
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Offline jimvela

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Re: Reaction Wheel Assembly Failures - Solved?
« Reply #3 on: 01/08/2019 03:30 pm »
Kepler's reaction wheels were made by Ball Aerospace.

No, they were not.  Ball Aerospace was the Kepler Spacecraft prime contractor.
Kepler's reaction wheels were made by Ithaco Space Systems.

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Is the manufacturer the reason they are so confident? Or are they a different type of design?

Many stories could be told about various reaction wheel manufacturers and their products by those of us whom have flown them.

There are plenty of issues besides newly discovered failure modes like CME-induced discharges.

It is certainly promising that this may lead to better designs and protective measures for wheels.