Based on what I saw, there are 2 base stations that are near enough to
serve most (but not all) locations in Ukraine (Poland and Turkey IIRC).

Elon Musk tweeted that someone was jamming then over Ukraine and that a software patch would fix it.

If someone is jamming the frequencies allocated to SpaceX with loud
elevator music, how can a software fix pass though the jamming? Or is
that more a question of filtering out the jamming singnal and only
keeping the frequency modulation used for the satellites?

If the modulation had to be changed (I guess similat to the Enterprise
changing shield modulation), wouldn't that affect worldwide service with everyone's terminals needing an update to change modulation?

Just curious how much of Elon's tweet is just PR vs actual science.


Secondly, and I ask this theoretically.

Most of the satelites are ~350km altitude. Branson and Bezos's joy
rides go to 100km. Say Russia had a joy ride that could reach 350km and
then fall back down. (0 orbital speed, only vertical speed).

Knowing the TLEs of the satellites, would it be feasable to launch
something straight up such that it get to satellite's position and
altitude just as the satellite passes there, causing satellite going
orbital speed to hit an object going at 0kmh ?

Just curious if this is a
-no brainer
-difficult but doable
-would require years to develop
-not even close to getting accuracy required for this


From orbital debris point of view, if a satellite at 25,000kmh hits a
static mass, would any portion of satellite end up with higher orbit, or
would all pieces of debris end up with less orbital energy (but perhaps
in elliptical orbit wth apogee higher than before, but burn up at perigee) ?


or does the collision itself generate an explosion at atomic level and
that explsion adds energy to both masses so the debris could go
anywhere, even at higher orbit?

--- SoupGate-Win32 v1.05
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JF Mezei submitted this gripping article, maybe on Monday:

Most of the satelites are ~350km altitude. Branson and Bezos's joy
rides go to 100km. Say Russia had a joy ride that could reach 350km and
then fall back down. (0 orbital speed, only vertical speed).

Oh, come on. You already know Russia has ASATs.

/dps

--
The presence of this syntax results from the fact that SQLite is really
a Tcl extension that has escaped into the wild. <http://www.sqlite.org/lang_expr.html>

--- SoupGate-Win32 v1.05
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On 08-Mar-22 10:20 am, Snidely wrote:

JF Mezei submitted this gripping article, maybe on Monday:

Most of the satelites are ~350km altitude.  Branson and Bezos's joy
rides go to 100km.  Say Russia had a joy ride that could reach 350km and
then fall back down. (0 orbital speed, only vertical speed).

Oh, come on.  You already know Russia has ASATs.

/dps

Though not thousands of them.

Also, would Putin really want to cause a massive space-debris problem
for foreseeable future?

Actually, on second thoughts, forget I asked that.

Sylvia.

--- SoupGate-Win32 v1.05
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On 2022-03-07 18:20, Snidely wrote:

Oh, come on. You already know Russia has ASATs.

Do these just pop up and down, or are those "orbital" missiles that get
to orbital speed and then smash against a satellite?


I was under the impression that so far, the "collisions" with satellites
have been done with the missile going to a similar orbit and then
purposefuly colliding with it. And if the orbit is similar enough, you
then have plenty of time to adjust trajectory to ensure you hit the
satellite.


If they launched in a retrograde orbit, can a missile's guidance really
be precice and quick enough to hit the satellite head on?

And my question still stands, whether you just launch a "blob" that ends
up with 0 speed in the path of satellite, does this result in parts of
the satellite gaining additional orbital energy?

In you use a retrograde missile that collides (with satelling going
north east at 25,000km and missile going south west at 25,000kmh, would
parts of satellite end up with higher orbital energy?

(not talking about any explosivles here, just mass hitting mass).

--- SoupGate-Win32 v1.05
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JF Mezei <[email protected]> wrote:

Based on what I saw, there are 2 base stations that are near enough to
serve most (but not all) locations in Ukraine (Poland and Turkey IIRC).

starlink.sx says there's also a Lithuanian base station. And all three
are NATO countries so he can't do anything about either.

Some playing around with starlink.sx suggests that all of Ukraine is
coverable by Starlink using those three base stations, even the areas
that has been under Russian puppet control for years which are much
further east than most of Ukraine which should be the hardest spot to
cover based on where the current base stations are.

They could in theory run out of "beam spots" which wouldn't show up on starlink.sx but that should be a prioritization question and Musk
likely has to prioritize Ukraine so it seems unlikely to be an issue.

Elon Musk tweeted that someone was jamming then over Ukraine and that a >software patch would fix it.

If someone is jamming the frequencies allocated to SpaceX with loud
elevator music, how can a software fix pass though the jamming? Or is
that more a question of filtering out the jamming singnal and only
keeping the frequency modulation used for the satellites?

There's many things that they could do that could help, it's
impossible to know what they're doing. But the jamming would need to
be pointed fairly precisely at the satellite which gives some hints of
a few of the things that might be possible.

Try to improve signal processing to reduce the impact is an obvious
counter move that I would be shocked if they wasn't working on this -
and this is enough to warrant what Musk said so far (no, he didn't
promise to "fix" it).

AFAIK the satellite antennas are also active?, in which case they
might be able to use that to localize where the jamming comes from and
then also use that to reduce sensitivity from the general area. Not
magic and not sure how MUCH they can beamshape things but any dB of
attenuation helps.

Also, in most cases there would a number of possible satellites that
SpaceX could have choosen to cover an area but likely only one or a
few would be used. So... what if they decided to swap around which one
are used in realtime, as long as the ground station knows the pattern
you've just made jamming significantly harder, especially if you can
also reduce jamming sensitivity using one of the methods above.

And that's just the ones obvious to someone without specialized
knowledge.

If SpaceX had a few more shells of satellites up this would get a lot
more complicated to jam too, but that takes time.

And as someone mentioned, the US military certainly wouldn't say no to
a more hardened Starlink so it has long-term benefits for Musk.
Basically they're getting field testing for free :-) And PR.

Secondly, and I ask this theoretically.

Most of the satelites are ~350km altitude. Branson and Bezos's joy
rides go to 100km. Say Russia had a joy ride that could reach 350km and
then fall back down. (0 orbital speed, only vertical speed).

Knowing the TLEs of the satellites, would it be feasable to launch
something straight up such that it get to satellite's position and
altitude just as the satellite passes there, causing satellite going
orbital speed to hit an object going at 0kmh ?

Russia do have real "direct ascent" ASATs with actual sane flight
profiles , their last intercept test was in November 2021 and created
a debris field both above and below that satellites orbit of 500km. It
was discussed a lot in the news given that some of this debris was in
orbits that could intersect with the ISS at 408 km.

However, it's very unlikely that Russia have (or can build in
reasonable time) anywhere near the numbers necessary to degrade
Starlink.

And.. There's no way they could hide what they did and deliberately
hitting an US satellite, even a civilian one like Starlink, would
effectively be an act of war against the US.

Congratulation, you may have found a (completely unrealistic) way to
make *China* decide that Putin has to go away, which would be very bad
for Putin given it's pretty much his last bastion of support.

OTOH there's also no way Putin wouldn't know the likely consequences
too.

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On 2022-03-08 11:59, Torbjorn Lindgren wrote:

starlink.sx says there's also a Lithuanian base station. And all three
are NATO countries so he can't do anything about either.

https://satellitemap.space doesn't show one in lituania. This is a nice addition to erve parts of finland and sweden that can still "see" the satellites that only go up to 55°. (but once polar orbit constellation
is fully deployed, I expect to start seeing more base stations. Note
that scandinavia is well connected to Internet by wireline so less of a
need for satellite.

Some playing around with starlink.sx suggests that all of Ukraine is coverable by Starlink

Yeah. I had a problem with my logic, I was looking at the service area
around a base station (about 1200km in ideal conditins), but a satellite
at 1199km from base station will itself have visibility on a circle of
1200km radius which means 2400 diametre (with base station at one end of
circle and customer st other end.

They could in theory run out of "beam spots"

are there beamspots, or does the satellite listen and broadcast in a
full 1200km radius ? Or is there 1 "wide channel" that listens on the
full footprint and then assigns individual beams to individual customers
and is able to track it all?

There's many things that they could do that could help, it's
impossible to know what they're doing. But the jamming would need to
be pointed fairly precisely at the satellite which gives some hints of
a few of the things that might be possible.

I hadn't considered the directionality of signals on the residentiual
antennas. Would Russian then need directional "elevator music"
broadcast that tracks satellite movements over Ukraine so the elevator
music can be targetted at every satellite while it is over Ukraine? If
so, could it be as simplke as changing satellite orbits and propagating
new TLEs to receivers but not to thge public TLE databases so Russia
wouldn't have up to date TLEs to target satellite with elevator music?

Or can something be done in an omnidirectional way to jam any/all
satellite dishes in an area?

Russia do have real "direct ascent" ASATs with actual sane flight
profiles , their last intercept test was in November 2021

Thanks. wasn't aware that these direct hits were just up and down
missiles. Does a 25.000kmh satellite hitting a 0kmh mass cause an
explosion due merely to the collision of matter? I assume those
missiles have explosives in them, but customer if it was just a box
filled with led weighting the same as the satellte. Newton would say
the result of the collision would be the box accelerated to 12,500kmh
and satellite decelerated to 12'500 (so both would drop out of orbit).
So curious on th mechanisms involved that accelerate portions of
satellite to a higher orbit.

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Addendum:

Reuters reports Viasat was also hacked.

https://www.reuters.com/world/europe/exclusive-us-spy-agency-probes-sabotage-satellite-internet-during-russian-2022-03-11/

--- SoupGate-Win32 v1.05
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