ISS Discussion Thread

[FleshJeb]

4 hours ago, Beccab said:

At what size does trackable become untrackable generally? 1 centimeter? 1 millimeter?

Maybe 0.3 cm, per this (which also has other useful information):

 

[JoeSchmuckatelli]

@FleshJeb Cool graphic!  Thanks 

[FleshJeb]

17 minutes ago, JoeSchmuckatelli said:

@FleshJeb Cool graphic!  Thanks 

The alternative was to post something about Mark 48 ADCAPs and debris fields at the bottom of the Atlantic, but this is much more productive.

[StrandedonEarth]

Okay, I’ll bite: how much propellant would be needed to raise the relevant part of the  ISS’ orbit above the worst of the debris stream?

Smooth move, Russia. A way to weasel out of ISS participation ASAP?

[sh1pman]

22 minutes ago, StrandedonEarth said:

Okay, I’ll bite: how much propellant would be needed to raise the relevant part of the  ISS’ orbit above the worst of the debris stream?

One full Starship tanker.

23 minutes ago, StrandedonEarth said:

Smooth move, Russia. A way to weasel out of ISS participation ASAP?

Not ASAP, debris will still need several years to reach as low as ISS orbit.

[mikegarrison]

5 minutes ago, sh1pman said:

One full Starship tanker.

Not ASAP, debris will still need several years to reach as low as ISS orbit.

Not all debris will have the same velocity vector. Some bits may already have paths that cross the ISS altitudes.

[sh1pman]

5 minutes ago, mikegarrison said:

Not all debris will have the same velocity vector. Some bits may already have paths that cross the ISS altitudes.

Maybe, but no tracked pieces have such tracks yet, as far as I know. According to the press release by Russia MoD, the lowest-reaching debris are 40 km above ISS altitude. If this was intended as a way to weasel out of ISS, looks like they failed

[tater]

34 minutes ago, mikegarrison said:

Not all debris will have the same velocity vector. Some bits may already have paths that cross the ISS altitudes.

Yeah, this is very true, and skews towards smaller pieces... I want to say the radars get down to 2cm objects.

27 minutes ago, sh1pman said:

Maybe, but no tracked pieces have such tracks yet, as far as I know. According to the press release by Russia MoD, the lowest-reaching debris are 40 km above ISS altitude. If this was intended as a way to weasel out of ISS, looks like they failed

The large bits will get spotted first, and the smallest debris will never be detected unless it hits something. Conservation of momentum means that the smaller pieces can be given higher velocities—and if retrograde, their orbits end up lower. So we would expect the debris most likely to hit ISS earlier (even if a very probability) to be those smallest, likely never detected pieces. Of course not being detectable ISS cannot maneuver to avoid them. Chances of a catastrophic hit are then much smaller, but small damage, leaks, etc are entirely possible.

[sh1pman]

13 minutes ago, tater said:

The large bits will get spotted first, and the smallest debris will never be detected unless it hits something. Conservation of momentum means that the smaller pieces can be given higher velocities—and if retrograde, their orbits end up lower. So we would expect the debris most likely to hit ISS earlier (even if a very probability) to be those smallest, likely never detected pieces. Of course not being detectable ISS cannot maneuver to avoid them. Chances of a catastrophic hit are then much smaller, but small damage, leaks, etc are entirely possible.

Of course, but I was responding to the part about “weaselling out of ISS”. If the MoD says there’s no danger, Roscosmos can’t use the debris danger as an argument in favor of withdrawal from the program.

[tater]

13 minutes ago, sh1pman said:

Of course, but I was responding to the part about “weaselling out of ISS”. If the MoD says there’s no danger, Roscosmos can’t use the debris danger as an argument in favor of withdrawal from the program.

Yeah, I was just talking about risk to ISS in general. Obviously over time the large bits will start crossing ISS as well as they decay over months/years.

[mikegarrison]

3 hours ago, sh1pman said:

Of course, but I was responding to the part about “weaselling out of ISS”. If the MoD says there’s no danger, Roscosmos can’t use the debris danger as an argument in favor of withdrawal from the program.

"Weaseling out of the ISS" was a silly comment. If Russia wants out of the ISS, all they have to do is stop sending cosmonauts and resupply ships up there. It's not like anyone can force them to do it.

However, I have about 0.00% trust in the Russian MoD being able to say that there is no risk to the ISS from this debris cloud that they just created for no good reason at all.

Edited November 17, 2021 by mikegarrison

[tater]

20 minutes ago, mikegarrison said:

However, I have about 0.00% trust in the Russian MoD being able to say that there is no risk to the ISS from this debris cloud that they just created for no good reason at all.

Left hand no knowing what the right is doing? It's really, really senseless.

[swjr-swis]

14 hours ago, tater said:

Chances of a catastrophic hit are then much smaller, but small damage, leaks, etc are entirely possible.

Not to mention the increased risk to EVA astronauts, with an undetermined and non-trackable number of bullet-like objects flying by the station in the near future.

[sh1pman]

12 hours ago, tater said:

Left hand no knowing what the right is doing? It's really, really senseless.

Roscosmos most likely knew, but couldn’t do anything about it. They have no authority over MoD, and the launch was from the army base nearby to Plesetsk, not the cosmodrome itself.

[kerbiloid]

If the sat was in a co-planar orbit, the relative speed would be lower than when its debris are on a cross-orbit.

Does the ISS keep some permanent orientation, or its rotation is chaotical?

[cubinator]

44 minutes ago, kerbiloid said:

Does the ISS keep some permanent orientation, or its rotation is chaotical?

ISS keeps one side facing the Earth most of the time. Like this:

Spoiler

Imagine the station moving out of the page towards you.

Sometimes they change the orientation if they need to dock something weird or have some other extraneous thing to do, but mostly it stays like this.

 

As for the orbital plane, the inclination always stays the same and the longitude precesses slowly due to Earth's oblateness.

[kerbiloid]

7 minutes ago, cubinator said:

ISS keeps one side facing the Earth most of the time.

Yes, but does it keep its orientation along the orbit.

I.e. are there permanently "windward" and "downwind" sides, relative to the new LEO meteor stream (delta-Tselinides)?

https://space.skyrocket.de/doc_sdat/tselina-d.htm

So, are there modules more dangerous than others?

Edited November 17, 2021 by kerbiloid

[Beccab]

57 minutes ago, kerbiloid said:

If the sat was in a co-planar orbit, the relative speed would be lower than when its debris are on a cross-orbit.

Does the ISS keep some permanent orientation, or its rotation is chaotical?

It depends on whether Nauka is docking or not

[kerbiloid]

7 minutes ago, Beccab said:

It depends on whether Nauka is docking or not

It's docked and nailed.

***

So, if there is a dangerous side, permanently facing the incoming delta-Tselinides, isn't it wise to delivere a bullet-protective screen, to put the station in meteor shadow?

[tomf]

1 hour ago, kerbiloid said:

It's docked and nailed.

***

So, if there is a dangerous side, permanently facing the incoming delta-Tselinides, isn't it wise to delivere a bullet-protective screen, to put the station in meteor shadow?

Looks like it pretty much keeps the same orientation but with a 15 degree wobble in what they call the torque equilibrium attitude or TEA.

https://www.forbes.com/sites/quora/2017/04/26/how-does-the-international-space-station-keep-its-orientation/?sh=17f52e433a18

[SSTO Crasher]

As you have probably already heard, Russia has tested a weapon on one of their own satellites, putting the crew of the ISS in danger and polluting space with hundreds of new peaces of junk. As @Matt Lowne says, we need to protect the space dolphins and space polar bears, and of coarse the space humans

[JoeSchmuckatelli]

1 hour ago, SSTO Crasher said:

As you have probably already heard, Russia has tested a weapon on one of their own satellites, putting the crew of the ISS in danger and polluting space with hundreds of new peaces of junk. As @Matt Lowne says, we need to protect the space dolphins and space polar bears, and of coarse the space humans

Start reading here: 

Odd - that was to Tater's post on this - recalculating

\

 

 

 

Recalculating

 

 

Edited November 18, 2021 by JoeSchmuckatelli

[AHHans]

The following popped up in my youtube suggestions. It's the communication between Huston (and/or SpaceX) and the ISS during the recent event when the ISS crew had to shelter from the debris cloud:

 

[RCgothic]

On 11/16/2021 at 10:59 PM, sh1pman said:

Maybe, but no tracked pieces have such tracks yet, as far as I know. According to the press release by Russia MoD, the lowest-reaching debris are 40 km above ISS altitude. If this was intended as a way to weasel out of ISS, looks like they failed

The MoD release is incorrect. According to LEOLab's Gabbard chart, at least 11 items with perigees below the altitude of the ISS (~410km) have already been detected.

They estimate 5-10x more smaller objects than this, which because smaller objects can be imparted with more retrograde velocity, many of those will also have low perigees.

So there are already probably a hundred new debris items crossing the ISS's orbit.

Furthermore, orbital decay will eventually bring all of these ~1500-2500 objects down through the ISS's orbit.

Almost all of these will be untrackable, and because the target was in a polar orbit orbital precession will eventually shape the debris field into a complete sphere. So there will be no advance warning of hazards, no possibility of manoeuvring to avoid the debris field, and no specific times in the ISS's orbit where additional precautions can be taken.

It's just a risk the station (and any others soon to launch) just have to live with from now on.

A spectacularly reckless and ill-conceived test.

[tater]

 

 

9 hours ago, RCgothic said:

A spectacularly reckless and ill-conceived test.

Except breaking stuff was the point. Not reckless, I think malicious.