
The death of a weather satellite as seen by SDR - guiambros
https://hackaday.com/2019/08/12/the-death-of-a-weather-satellite-as-seen-by-sdr/
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madaxe_again
An aside: I’m pretty sure I saw the death of a satellite in full visual glory,
three nights ago. Was watching for meteors, and a large bright blue streak
came in heading due south, looking slow and shallow, and left a smoke trail
visible through binoculars. Same plane as I see a lot of polar orbits on from
here. I’ve searched to see if I could find anything known that was deorbiting
then, but couldn’t. The fireball would have started somewhere over Spain (was
looking south from France), probably ended in South Atlantic. I thought I’d
mention it here, as if anybody has a clue, it’ll be you lot.

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beefok
Meteors can produce smoke trails and I have seen them create them!

[https://www.youtube.com/watch?v=tbpiOWs6zPU](https://www.youtube.com/watch?v=tbpiOWs6zPU)
(note: not my video, just one I googled)

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Thrymr
Three nights ago was near the peak of the Perseids meteor shower, too.

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ad404b8a372f2b9
Next one will be Meteor M2, it's experiencing malfunction after malfunction,
breaks my heart.

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FatalLogic
The problem is believed to be the spinning mirror which scans the image
sensor's viewpoint across the Earth. The motor driving the mirror has a
problem, so it doesn't spin consistently any more. It is supposed to spin at
360 RPM.

Could it be possible to spin the entire satellite and get intermittent
coverage and reception?

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msl
Satellites usually need to point their solar panels and high-gain antennas
properly in order to stay powered to be able to communicate with ground
stations, although this particular satellite seems to have been unable to use
its high-gain antenna anyway and relied on an omnidirectional one anyway.
Another issue would be thermal management as it is possible that not all parts
of the satellite were designed to deal with direct sunlight. I would be more
worried about all the sensors, though. The days of secondary electron
conduction tubes [1] might be long over, but many instruments still prefer not
to be pointed directly at the sun.

Speaking of those other sensors, spinning the satellite would mean pointing
all of them away from where they are supposed to be looking – not necessarily
a net win.

Finally, trying to spin the satellite at anything approaching 360 RPM might
end up _dramatically_ shortening the mission [2].

[1]
[https://en.wikipedia.org/wiki/Apollo_12#EVAs](https://en.wikipedia.org/wiki/Apollo_12#EVAs)

[2] [https://youtu.be/AqeJzItldSQ?t=90](https://youtu.be/AqeJzItldSQ?t=90)

EDIT: In case you do not feel like watching the video, [2] shows a Little Joe
II rocket
([https://en.wikipedia.org/wiki/Little_Joe_II](https://en.wikipedia.org/wiki/Little_Joe_II))
breaking up due to an excessive roll rate (around 56 RPM)
([https://en.wikipedia.org/wiki/A-003](https://en.wikipedia.org/wiki/A-003)).

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orbital-decay
_> trying to spin the satellite at anything approaching 360 RPM might end up
dramatically shortening the mission_

A recent, quite a spectacular example of that was the Hitomi X-Ray observatory
which went into uncontrolled spin due to a faulty inertial unit.

[https://en.wikipedia.org/wiki/Hitomi_(satellite)#Loss_of_spa...](https://en.wikipedia.org/wiki/Hitomi_\(satellite\)#Loss_of_spacecraft)

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fred_is_fred
Why boost-up to a graveyard orbit rather than "booting-down" to decay and
presumably burn up on re-entry?

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positr0n
As other commenters mentioned, it is just too far away to do that.

To give you a sense of scale, if you reduce Earth to the size of a basketball,
low earth orbit (space station, starlink, etc) would be less than a quarter
inch above the surface of the basketball. Geosynchronous orbit is a ring
around the equator 26 inches above the surface of the basketball.

This is also why Starlink is incomparable to existing satellite internet
solutions.

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Nition
There's a nice visualisation of the different orbits at
[http://stuffin.space](http://stuffin.space)

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cmroanirgo
Wow. Thanks for that, what a great visualisation, and updating too!

Edit: This is the satellite being talked about in the article
[http://stuffin.space/?intldes=1998-030A](http://stuffin.space/?intldes=1998-030A)

