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SpaceX Refused to Move Satellite at Risk of Collision with a European Satellite

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Re: SpaceX Refused to Move Satellite at Risk of Collision with a European Satellite

#191
post #164

Earlier quoted context omitted.

SpaceX playing chicken with cheap disposable Starlinks against multibillion euro public satellites does make space dangerous.

Nobody is playing chicken here. The SpaceX satellite is for all intents and purposes inert, since it is incapable of significantly adjusting its orbit. You know the old joke about the US Navy warship giving way to the second class seaman, right?

>The SpaceX satellite is for all intents and purposes inert, since it is incapable of significantly adjusting its orbit.

If SpaceX is actively deorbiting the satellite, it's not inert.

Re: SpaceX Refused to Move Satellite at Risk of Collision with a European Satellite

#192

Being a lover of Space and SpaceX, this incident highlights why a goldilocks paradigm for regulation needs to exist for space. Not too much that it stifles innovation. Not too little that someone ends up Kesslerizing Near-Earth space. Current regulations are largely successful at promoting commercial space flight, but there is a big transparency gap between civilian space flight agencies and private entities. Transpa…

I'm not entirely convinced this is the argument. From what I've read so far, it seems that ESA was uncomfortable with the possibility of a collision to a degree that SpaceX could possibly be quite comfortable with - ESA wants > 1km distance, whereas SpaceX might be comfortable with much closer - they are quite different constellations. Who has the right to dictate who has priority / which criteria is the right one? I…

I think you have this right, not so much about appetite for risk but maybe telemetry on SpaceX's satellite (or a number of satellites in the swarm) gave them sufficient confidence that there was no issue?

Given SpaceX routinely send resupply missions to the ISS I would assume they have a fair amount of confidence when it comes to knowing the position of their vehicles.

Re: SpaceX Refused to Move Satellite at Risk of Collision with a European Satellite

#193
post #79

Earlier quoted context omitted.

Starlink satellites are only approximately 350 miles up, which means any debris gets brought down by atmospheric drag very quickly. A million satellites in that orbit could not cause kessler syndrome.

That's not quite accurate. Firstly,the debris will destroy everything in LEO, maybe including ISS, then debit in a few months. Secondly, some of the debris will probably end up in higher orbit and stay there for a long time, just like was the case with India and China ASAT tests. Then they can pose a risk for centuries

> Secondly, some of the debris will probably end up in higher orbit and stay there for a long time

The average height of the orbit may go up, but depending on the direction of the collision the perigee will decrease by some amount, so there will still be a considerable amount of atmospheric drag. The Chinese ASAT test was in a much higher orbit, which is why so much of the debris is still troublesome. Most of the debris from the Indian ASAT test is gone, and the rest will probably be gone in a year or two.

Re: SpaceX Refused to Move Satellite at Risk of Collision with a European Satellite

#194

Earlier quoted context omitted.

Ok, so by which physical method do they have better telemetry?

Definitely GPS, probably star trackers too. Not a good idea to have a single point of failure on position knowledge when your whole scheme depends on putting small beams in the right places.

How do you pull a TLE (or any sort of ephemeris other than rotation/attitude) out of star tracker data?

Re: SpaceX Refused to Move Satellite at Risk of Collision with a European Satellite

#195
post #161

Earlier quoted context omitted.

> Not acting because you don’t have choice doesn’t count as refusing. It does beg the question whether you should be there at all.

Every deorbiting satellite passes through lower orbits. Many of them passively.

They are are where they are by choice. It's a de-orbiting exercise. If they can't maneuver where they are now because of their propulsion design, they have the same problem in a normal orbit. So I wonder whether this design enables them to be a good and safe neighbor.

Re: SpaceX Refused to Move Satellite at Risk of Collision with a European Satellite

#196

Being a lover of Space and SpaceX, this incident highlights why a goldilocks paradigm for regulation needs to exist for space. Not too much that it stifles innovation. Not too little that someone ends up Kesslerizing Near-Earth space. Current regulations are largely successful at promoting commercial space flight, but there is a big transparency gap between civilian space flight agencies and private entities. Transpa…

It just comes across as them being arseholes since no reason was given.

Typical 'better to ask permission than forgiveness' fuckery that companies featured on this site are famous for.

Re: SpaceX Refused to Move Satellite at Risk of Collision with a European Satellite

#197

Being a lover of Space and SpaceX, this incident highlights why a goldilocks paradigm for regulation needs to exist for space. Not too much that it stifles innovation. Not too little that someone ends up Kesslerizing Near-Earth space. Current regulations are largely successful at promoting commercial space flight, but there is a big transparency gap between civilian space flight agencies and private entities. Transpa…

I'm not entirely convinced this is the argument. From what I've read so far, it seems that ESA was uncomfortable with the possibility of a collision to a degree that SpaceX could possibly be quite comfortable with - ESA wants > 1km distance, whereas SpaceX might be comfortable with much closer - they are quite different constellations. Who has the right to dictate who has priority / which criteria is the right one? I…

Or just that Space doesn't care about losing 1 Satelite.

Re: SpaceX Refused to Move Satellite at Risk of Collision with a European Satellite

#198

Earlier quoted context omitted.

Perhaps not a bad plan if you want to destroy everyone elses but USA’s sats

A collision would result in 1000s of pieces of debris that would affect everyone’s satellites. Repeated collision would make these orbits unusable until gravity and atmospheric drag naturally deorbit the fragments.

afaik thats not really long time

Re: SpaceX Refused to Move Satellite at Risk of Collision with a European Satellite

#199

Earlier quoted context omitted.

A collision would result in 1000s of pieces of debris that would affect everyone’s satellites. Repeated collision would make these orbits unusable until gravity and atmospheric drag naturally deorbit the fragments.

afaik thats not really long time

"Not a very long time" is pretty vague.

Also, even if the impact is limited in term of long lasting debris, losing several satellites, and as a consequence losing the services they provide plus having to replace them is definitely a large impact which will last years.

Re: SpaceX Refused to Move Satellite at Risk of Collision with a European Satellite

#200

Earlier quoted context omitted.

In addition: > the satellites, each weighing 227 kilograms, are “capable of tracking on-orbit debris and autonomously avoiding collision.” But for this incident, this system does not seem to have been used for some reason "does not seem to have been used" - if SpaceX made no statement we can't really tell? Maybe they were confident that their collision avoidance would simply work.

They were testing their "deorbiting maneuvers". Probably got annoyed that they'd have to restart testing. > Maybe they were confident that their collision avoidance would simply work. Just like Tesla's? If your satellite is worth $100K and the other one is worth $2.3B, perhaps you have a little less to lose.

I’m pretty sure they’d have a lot more to lose by intentionally causing a crash, right before launching a whole constellation of the same satellite.
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