
New video of Intelsat 29e satellite reveals dramatic “anomaly” - based2
https://arstechnica.com/science/2019/04/new-video-of-intelsat-29e-satellite-reveals-dramatic-anomaly/
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cameldrv
I’ll just leave this here: [https://spacenews.com/russian-satellite-maneuvers-
silence-wo...](https://spacenews.com/russian-satellite-maneuvers-silence-
worry-intelsat/)

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Gravityloss
Extremely fascinating, thank you.

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CamperBob2
Very cool video, never seen anything like it. What sort of telescope is used
to capture imagery like that?

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pram
I'm impressed as well. Are there companies that constantly take video footage
of satellites for monitoring?

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sizzzzlerz
FTFA:

"However, new data from ExoAnalytic Solutions, which has a network of 300
telescopes around the planet to track satellite movements in geostationary
space, shows the situation has gotten markedly worse."

Apparently, there are.

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joeyspn
Orbital debris from India's anti-satellite test?

[https://www.theguardian.com/science/2019/apr/02/a-terrible-t...](https://www.theguardian.com/science/2019/apr/02/a-terrible-
thing-nasa-condemns-indias-destruction-of-satellite-and-resulting-space-junk)

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sreevisakh
Intelsat 29e was in the geostationary orbit at an altitude of 36000 km. The
Indian ASAT test was at an altitude of 300km. For any debris to reach that
altitude, the explosion has to boost its velocity by 2 to 3 km/s. This is
highly unlikely.

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baybal2
For a debris the mass of a screw, it's not that far fetched. Moreover, orbital
collision can launch it with an enough velocity to reach GEO orbit retrograde.
You need "just" 10 to 15 kJ of kinetic energy. A retrograde collision will
then be able to liberate few times more energy.

[https://instacalc.com/42836](https://instacalc.com/42836)

If that happened anywhere close to the apogee of the Indian ASAT test debris,
and in same ecliptic, it's very likely it

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sreevisakh
That figure of 10 to 15 kJ can be very misleading about what it takes to
propel something to such speeds. Put into 'TNT equivalent', it would take the
entire energy of 50g of TNT to boost a 100g bolt by just 2 km/s. It's
difficult to concentrate that much energy per mass in an explosion (which is
leaky). To add further, most ASATs (including the Indian test) doesn't use
explosives, but make a direct hit (hit to kill) from a suborbital trajectory
(one that has much less energy than an orbital interceptor). The boosting
comes mostly from fragmentation mechanics.

The satellite will still fragment with some fragments getting boosted up to a
higher velocity. In addition, the propellants on the satellite and the kill
vehicle might add velocity to the fragments too - though arguably less energy
than if it was TNT. So, previous studies on US and Chinese ASAT debris cloud
can be considered for a fair assessment. The Chinese test was at a higher
altitude of 865km and US test was at a similar altitude. 'Gabbard plot' of
these debris show the maximum altitude to be only around 3900 km for both
tests. There could be untracked particles at higher orbits, but remember that
the velocities of the debris is a random distribution (not sure which one)
that tapers at extreme values. Odds of any debris crossing geostationary orbit
is very low.

There is one additional significant point to consider. Boosted orbits mostly
retain the altitude at interception (it's the diametrically opposite part of
the orbit that gets affected). This is evident from the Gabbard diagram, where
apogee and perigee plots intersect in cross shape with a horizontal line at
the altitude corresponding to intercept altitude. This means that most debris
come down to atleast 300km. Since the drag at this point is significant, the
apogee (maximum altitude) of the debris would decay rapidly - thus mitigating
risk to higher satellites. With that odds, a debris crossing geostationary
orbit could more likely be from some previous in-orbit explosions than from
any ASAT test.

Ref: [https://sattrackcam.blogspot.com/2019/03/debris-from-
indias-...](https://sattrackcam.blogspot.com/2019/03/debris-from-indias-asat-
test-how-long.html) [https://sattrackcam.blogspot.com/2019/04/why-even-low-
altitu...](https://sattrackcam.blogspot.com/2019/04/why-even-low-altitude-
asat-intercepts.html)
[https://celestrak.com/publications/AMOS/2007/AMOS-2007.pdf](https://celestrak.com/publications/AMOS/2007/AMOS-2007.pdf)

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baybal2
That's a proper argument. I did not think that far

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KineticLensman
TL;DR: The anomaly includes propellent out-gassing events from the spacecraft,
creating a dissipating halo and several pieces of debris. The satellite is now
drifting at 1 degree a day. Cause as yet unknown although an external impact
(debris or micro-meteorite) is hypothesised.

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topspin
Now it's a geostationary comet.

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ilaksh
I have heard about a lot of debris in space. How much is there in general and
how much is at that height?

I wonder if there are simulators that can predict the likelihood of
collisions.

Also how common are meteorites and things coming from space? And what are the
chances of being hit by those?

I am guessing a large object like the space station has a bigger chance of
being hit by something.

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akimball
My great concern is that satellite fission may cascade, enveloping the Earth
in a debris cloud and taking away access to space.

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orbital-decay
Kessler syndrome is not a big concern for GEO, which is quite a "lazy", well
organized and sparsely populated orbit where high relative velocities are
rare, compared to highly crowded synchronous polar orbits, especially the
lower ones.

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akimball
Good point. I infer that any cascade impact from i29e will be felt in lower
orbits.

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avs733
That video is just rough to watch for me as an engineer. Poor little
satelite..

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emilfihlman
I think it's funny how "not possible" or "not even remotely likely" answers
are just dismissing the possibility of this being debris from low earth orbit.

Sure, it's unlikely. But unlikely bugs do happen in computation, too. We
_cant_ know.

