Could a leaky capacitor be at fault on ESA's Sentinel-1B?
- Reference: 1650907805
- News link: https://www.theregister.co.uk/2022/04/25/sentinel_1b_update/
- Source link:
The satellite, launched in 2016 aboard a Russian Soyuz rocket from the Arianespace facility at Kourou in French Guiana, remains under control. However, [2]power problems have rendered its C-band Synthetic Aperture Radar (C-SAR) instrument pretty much useless, thus defeating the point of the spacecraft.
Sister spacecraft, Sentinel-1A, has continued to collect data despite recently having to [3]dodge some debris .
[4]
While a leaky capacitor is all too familiar to engineers repairing faulty electronics on the ground, dealing with one in orbit is altogether trickier. This particular capacitor is part of the main and redundant regulators of the 28V bus that supplies power to the SAR electronics. Earthbound boffins reckon the failure mode is possible, but remain open to other possible causes for the anomaly.
[5]
[6]
The good news is that there have been signs of life during the repeated attempts to switch it back on. On one attempt to fire up the prime regulator, engineers noted that it remained on for 4.4 seconds before being autonomously switched off.
This was the first time this had happened since recovery attempts began at the start of the year – and has given engineers hope that perhaps the issue is one of degradation rather than a permanent fault.
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The next step is going to be turning the heaters of the power supply on and off in order to vary the temperature. "This could influence the behavior of the regulators," said a hopeful ESA before parroting the line that it was still too early to write off the hardware as permanently failed.
[8]Auctioneer puts Space Shuttle CPUs under the hammer
[9]ESA: Fly me to the Moon, just not on a Russian rocket
[10]First rocket launch from UK soil now has... a logo
[11]The Register gets up close and personal with ESA's JUICE spacecraft
Spacecraft steerer Thomas Ormston [12]said "we've got a busy few days heating things up and cooling them down" as engineers continued the recovery effort.
A [13]comparison was also drawn to ESA's Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) spacecraft, which suffered a failure in 2010 when data stopped being downlinked. Science resumed when the temperature of the floor hosting the computers was raised by 7°C.
While the Sentinel-1B issue is quite different, Ormston remarked: "There is a bit of deja vu going on..." as engineers got busy with the heaters.
The conclusions of the anomaly review board are expected in May. A third satellite in the Sentinel-1 series, Sentinel-1C, is set to launch next April... [14]onboard a Vega-C this time, rather than a Soyuz. ®
Get our [15]Tech Resources
[1] https://scihub.copernicus.eu/news/News01026
[2] https://www.theregister.com/2022/01/19/esa_sentinel_1b/
[3] https://www.theregister.com/2022/04/04/sentinel_1a/
[4] 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=2YmcaB6WqlYCoCutunR-Y7QAAARI&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[5] 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=44YmcaB6WqlYCoCutunR-Y7QAAARI&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
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[7] 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=44YmcaB6WqlYCoCutunR-Y7QAAARI&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[8] https://www.theregister.com/2022/04/14/space_shuttle_computer_auction/
[9] https://www.theregister.com/2022/04/14/esa_council/
[10] https://www.theregister.com/2022/04/12/rocket_result/
[11] https://www.theregister.com/2022/04/11/esa_juice_visit/
[12] https://twitter.com/ThomasOrmston/status/1517819396000997379
[13] https://twitter.com/eelcodoornbos/status/1517825103563833345
[14] https://www.arianespace.com/press-release/arianespace-wins-new-contract-to-launch-sentinel-1c-observation-satellite-on-board-vega-c/
[15] https://whitepapers.theregister.com/
Re: This particular capacitor is part of the main and redundant regulators
Maybe they mean redundancy but it still does not make sense.
It can be in one of the other but not both. If it is in both then there is no redundancy!
Could be they have a broken capacitor but they do not know which one and there is a number of them being used. Some are used in the by the main regulators and some other ones are used in the backup regulators so the system has some redundancy.
Re: This particular capacitor is part of the main and redundant regulators
Now why did I think "offcom"?
squirty can
A can of squirty freezer spray and a soldering iron tip in close proximity will quickly locate the failed part. Oh hang on, that might not be so easy.
Re: squirty can
It should already be pretty cold up there. Just take your helmet off and breathe on it and see which part doesn't get frosty - errm perhaps not.....
Leaky ceramic?
Ceramic capacitors have nothing to leak since they're metal and ceramic. Maybe they mean shorted? Hopefully there's more than one cap on the power supply. If they can get the shorted cap hot quickly it might pop itself off the board.
I'd bet it's a damaged switching transistor. The symptoms are similar but with no chance of fixing it. Hopefully there's another power supply too.
Re: Leaky ceramic?
Leaky in this context means it has parallel internal resistance so there is a DC current flow.
This is common in ceramic and tantalum capacitors.
Nothing to do with your perception of an electrolyte leak in an electrolytic capacitor.
(Speaking as a former capacitor design engineer).
Re: Leaky ceramic?
'Leaky in this context means it has parallel internal resistance so there is a DC current flow.'
Exactly this!
Strange
If you think of all of the electronic devices you have the only went through a cursory functionality test at the factory using parts from a huge bin. Now look at the process to build a satellite where every component is hand selected and systems tested multiple ways to verify operation and they still get a higher percentage of failures than in the consumer world (quantities of satellites being rather tiny). These parts are also the highest spec from a quality vendor, not sourced on price alone or at all in most cases. I have to wonder if the process is flawed. Space is a difficult environment to design for, but it's not that hard.
I'll admit that MLCC caps can be a PIA.
Re: Strange
"higher percentage of failures than in the consumer world"
All hardware eventually fails so in both cases it's 100%. The difference is when it's some expensive satellite then you read about it.
"quantities of satellites being rather tiny"
You are measuring it wrong. A satellite has millions of parts compared to a consumer piece of kit having thousands. And still the mean time to failure for a satellite is in decades (granted some is DOA) versus for the consumer kit in years (granted some lasts decades).
Re: Strange
Don't they still make them on pairs?
One to test, one to send ip.
check the supply chain...
see if the dodgy components came from the same source, factory, lot #......
This particular capacitor is part of the main and redundant regulators
“You keep using that word. I do not think it means what you think it means.”