Russia: It isn't just us – a bit of an old US rocket might get as close as 5.4km to the ISS Russian news agency TASS has reported that a chunk of a US Pegasus carrier rocket is due to whizz past the International Space Station (ISS) at a minimum distance of 5.4km this week. In a report that entirely failed to mention the debris cloud created by a Russian Anti-Satellite Test a few weeks ago, space agency Roscosmos was …
Skills in practice: "what about."
In this case, "what about" is a 56 year old booster launched before Kessler did his calculations, before we had a clue about space debris, before there was an ISS to intentionally involve in a orbital path of debris purposely created and long after we knew better.
Falcon upper stages left behind now mostly in service of the orbital kitty video delivery system? That's a legitimate problem, but not one the authors of "what about" worry over, based on their own seemingly pointless action. It's worth noting also that upper stages made by SpaceX passivate as part of their normal procedure, won't fragment unless struck. Unlike the Fregat still used by the "what about" authors which routinely fragments after use, and the continuing problem of SOZ ullage motors which continue to be deployed and continue to routinely fragment due to "we don't care."
Indeed, the puzzle answer for _why_ the Russians did this might lie in work also done decades ago, the exploration of geopolitical posturing with nuclear weapons by Herman Kahn and others. Sending a message to the effect of "we're crazy" can have a strategic purpose.
But the "what about" authors can depend on the reliability of ignorance. That fog can be penetrated in this case by visiting ARES' https://orbitaldebris.jsc.nasa.gov/quarterly-news/
[I think I've got my spacecraft mixed up here; the Pegasus stage in question is probably the later Northrop-Grumann variety. But: passivates, isn't intentionally fragrmented in a dangerous manner.]
Generally, we've been filling up low orbit and to some extent high orbit for decades without giving it much thought. It seems like it's only been in the last 10 years or so where we are having more and more launches every month. The sats that the Musky one is launching 50 or so at a time is also a problem... a big problem.
While it's true that what goes up will (for the most point) come back down but that's a function of us sitting back and waiting unless someone comes up with a cheap and reliable way to de-orbit all the junk and dead sats.
I suspect that in not too many years that space will be off-limits to us Earthlings since the risk of collision will be too high.
Tiny junk is a big problem both in terms of statistics and the impossibility of de-elevation.
https://en.wikipedia.org/wiki/Laser_broom
Technically it's probably doiable now. Politically is a whole different kettle of fish
Brooms CAN take down the even smaller stuff but it requires opportunistic shooting into the debris streams and hoping, rather than actaully targetting individual objects (shotgun vs rifle)
It has already reached the stage where launch windows need to be adjusted to factor in "known" space debris orbits to allow for probable safe passage. And even then a tiny fleck of space junk that is not currently being tracked (anything that is smaller than 5 centimetres or 2 inches in diameter) could easily be travelling ~29,000 kilometres per hour (~18,000 miles per hour), or over 5 times the maximum speed of the highest velocity rifle bullets on earth (~1500 meters, or ~5000 feet, per second), could do enough damage to destroy most launches.
I'll leave this here in case you have not seen it: http://stuffin.space/
The Starlink sats are designed to de-orbit at the end of their service lives, so they will not be left around as junk for any significant amount of time (though it's not "instantaneous", as that requires a lot of propellant). I know it's going the other way, but Scott Manley has a good video showing how they are moved into orbit - around about 7 minutes in, it mentions that if any aren't working correctly after initial deployment, they can simply be commanded to re-enter the atmosphere.
Similarly, the Falcon 9 second stages are intended to de-orbit once they have deployed. One or two have suffered failures that means this hasn't happened, but that's very rare.
"I suspect that in not too many years that space will be off-limits to us Earthlings since the risk of collision will be too high."
I would even postulate that Russia wants to prevent the USA commercialising and thereby monopolising space (and for both LEO and HEO).
So, a few thousand fragments of Russian debris orbiting at 22,000+ MPH might be enough to put some Musk/Bezos/Branson types off, from launching ever more bits of American made space hardware.
"So, a few thousand fragments of Russian debris orbiting at 22,000+ MPH might be enough to put some Musk/Bezos/Branson types off, from launching ever more bits of American made space hardware."
Unless, of course, that debris in in a similar orbit to one you want to use, in which case your sat is also orbiting at 22,000+ MPH so the closing speed for any potential collision is very small.
We are not in a good situation with regard to debris, but I do wish people would stop bandying about "Big Scary Numbers" for orbital velocities when in the majority of cases, the closing speed is massively lower.
There are clever people here who, more so than me, understand this stuff. We commentards are always taking the piss out of stories showing marketeers deliberately misrepresenting things by using best/worst case "Big Scary Numbers". We all know relative velocities of objects in space likely to come into contact with each other is more like the "up to" speeds of broadband. The max. is possible, but generally unlikely :-)
" when in the majority of cases, the closing speed is massively lower."
Sooner or later they're going to be facing head on or near-as-dammit thanks to orbital precession mechanics on uncontrolled objects and even a "glancing blow" is catastrophic at these speeds
We've already got documented cases of the kinds of damage that can be done from shuttle days (paint flecks hitting the glass) and there used to be some footage kicking around showing how a steel 3mm nut could excavate a hole the size of a grapefruit in an aluminium block
The significance of that being that the nut is too small to track even now (back when it was published the smallest trackable objects were about 20cm)
For biologicals it looks like whipple shields help and the inflatables such as Bigelowe modules are essentially supersized versions of this, but they can only do so much and they add a lot of mass on smaller craft
It's better to try and not leave shit up there in the first place and a coordinated international cleanup effort would go a long way - this isn't going to happen whilst the most active player insists on dickwaving and trying to shut everyone else out instead of accepting that they're not the only game in town and cooperation is better than conflict
I recall when, as a child, being told the oceans were an inexhaustible source of food. They are so big we can never affect them. Aye, right!!! We've run fish stocks down (and just calling them "fish stocks" assumes we own them by right), and the use of the oceans and feeder waterways as garbage disposal routes is now coming back to bite us. The HHGTTG said: "Space is big, very big..." - big enough that we could never use the puny resources of our planet to pollute it in any significant way, but the bit of space we actually occupy is quite limited and we're managing to do to that what we've done to the oceans (and our atmosphere).
"unless someone comes up with a cheap and reliable way to de-orbit all the junk and dead sats"
We already have a pretty good idea how to do that. Ground-based ablative lasers can do the job with pretty much off-the-shelf parts. You only need relatively low power to evaporate very small amounts of an object, which results in a change in velocity. It's effectively an ion engine, but the power is on the ground and the propellant is the body of the object instead of a separate fuel supply. Best of all, since you only need to target small objects for a fairly short time, you can even clean up all the mess of little bits that aren't currently tracked - the problem at the moment isn't that we can't see them at all, but rather that it's too difficult to track them in the long term.
The problem, as is so often the case, is entirely political. It's impossible to create a cheap and reliable way to deorbit junk that isn't also a cheap and reliable way to deorbit anything else. As we've seen recently, anti-satellite weapons cause all kinds of fuss because it's difficult to see them as anything other than a MAD situation. Sure, a lot of the news and discussions talk about them as an issue for creating debris, but the political concerns are very much of the military variety. Now think how foreign nations might react to the building of a weapon that can untraceably take out any orbital object at any time.
Like so many of the problems humanity causes itself, it's not that we don't know how or aren't capable of fixing it, it's simply that we're collectively not willing to do so.
"I suspect that in not too many years that space will be off-limits to us Earthlings since the risk of collision will be too high."
On the other hand, looking at other tech and it's advances over time, we seem to be at a tipping point in terms of much cheaper access to space. Whether humanity can deal with the problem before it becomes impossible is a function of how quickly we can get economically viable access for disposal missions.
I do wonder if any of the "IoT" sat link constellation are looking at using some of their money to help our or if that could only ever happen if they see a risk to their business model.
On page 20 of this big pdf I found that every Falcon 9 stage 2 launched to LEO since CRS-3 (2014-04-20) has been intentionally de-orbited. Starlink satellites are delivered to a parking orbit of 440km (ISS is at 420km). ISS astronauts on a spacewalk de-orbit small stuff by throwing it downwind so even a tiny amount of propellant is enough de-orbit a stage 2 that has deployed its payload.
While they will de-orbit a little earlier than the ISS would if it wasn't given a nudge upwards every so often I think the primary reason ISS astronauts throw stuff 'downwind' is because the relatively tiny difference in velocity* mean it will be a long time before ISS catches up with it and by then the likelihood of it being anywhere near the ISS flight path is very small.
* The ISS is moving at something over 28,000km/h I doubt a good throw while in a space suit could reduce that by more than 20km/h.
It is not humanly possible to de=orbit anything by throwing it backwards, I can't be bothered to find it but Scott Manley has debunked this in one of his videos.
Page 20 of that PDF contradicts your words where it says the first 9 Falcon 9 flights:
"• Left in LEO to decay == This has been the case for Falcon 1 Flights 4 & 5 which remain in a nearly equatorial LEO to this day, as well as the first 5 Falcon 9 flights - of which COTS1
performed an unannounced upper stage restart boosting it into a 290x10,700km orbit &
CASSIOPE, which attempted a "sideways" upper stage restart which failed, stranding it in a
900km polar orbit. "
BTW I think that PDF comes across very disjointed and poorly put together which is surprising considering the author of the PDF is a Journalist and was an aerospace engineer. Perhaps he is past his best.:-(
"Falcon upper stages left behind now mostly in service of the orbital kitty video delivery system"
Mostly don't happen. Watch the orbital track for these things, it's eliptical and dips into the upper atmosphere enough to come down very quickly
Ever since Kessler did his thing it's been a requirement to ensure that launch equipment comes out of orbit quickly (usually within 3 months), particularly bearing in mind that during the 1980s there was a spate of explosions of "derelict" 1960s upper launch stages which had been left in orbit (the immediate change was to require all tanks be vented before the vehicle was shut down and "safed". After Kessler, deorbit planning became mandatory)
The really irritating thing about space junk is that we mostly have the technology to being the problematic stuff down fairly quickly from the ground (laser brooms) but despite having the potential to clear the "sand" out of orbit the perception is that anyone deploying one would be able to bring down "unfriendly" satellites the same way and so they're treated as a space weapon.
Having a multinational task group operating something like this with all spacefaring nations having oversight (UN proposal?) and agreement on what's done would solve the issue, but.... politics (it's not a coincidence that these big missiles being waved around look like gonad extensions)
It really is the "sand" (anything under 5cm or so) which is problematic and causing most of the problems right now because it simply can't be tracked. Sooner or later a hypervelocity bolt or nut is going to make mincemeat ouf of something important (vs the paint fragments and other small shit that's already caused issues)
Note also that they said "more than" 5km ... I, personally, will be passing the ISS more than 5km away several times per day. Or, if you prefer, "a minimum distance of 5.4km" ... so about as close as Paddington is to The City[0][? Ohhh ... scary!
Propaganda. Or, in the words of the prophet, "smells like bullshit to me".
[0] As the crow flies, of course.
An estimate for Canadian Geese would not go amiss, thanks.
But then when I finished typing that last sentence, I can see my cat clawing at the window to a pigeon shitting all over the balcony. So I can do pigeons, anyway.
What's the old saying? Men plan, women and cats laugh... or something?
*sigh*
I withdraw my request.
One advantage of bigger debris is it's a lot easier to observe and thus predict (plus there tends to be a lot less of it). Given the laws of physics haven't changed lately, those estimates should be pretty good.
The one detail that might complicate estimates is that larger debris in LEO has more atmospheric drag and this means it's orbit will change (decay) a lot quicker than something smaller. I suspect that's probably only significant over a timescale of months rather than hours though.
An object that is, say, ten times larger than another will have a thousand times the mass and a hundred times the cross-sectional area. So the _force_ of drag will indeed be a hundred times larger for the larger object. The _acceleration_ (force divided by mass) will be ten times less. Sort of the way a snowflake experiences atmospheric drag and falls slowly in the way that a snowball doesn't.
In theory and practice, this does mean that the smaller stuff gets dragged down more quickly. Though in most cases, not quickly enough.
You're right on the observability issue, though. If I recall correctly, objects down to about ten cm are currently reported by CSpOC (US organization that collects radar data and provides orbital elements). The new "Space Fence" is supposed to raise that by a lot, so I assume it'll do so by tracking smaller objects (which certainly seems like an excellent idea in any case). But even a one-cm object hitting at several km/second will do serious damage.
Non-luminous object 3 and a third miles away?
Nope. Having ridden the slowly exploding bomb into LEO and having sat in a thin-walled tin can for x days awaiting the arrival of powdered Soviet satelite, the threat of something I won't see coming speeding past (well, not so much, orbital mechanics being what they are) a few miles away is not going to consume much nightmare time in the Steviehead.
Get a grip, man.
Can any Russian speakers translate the phrase "A Big Boy Did It And Ran Away" for me please?
This problem isn't going to go away though, we've got more and more traffic going in to space seeing as it has become the new billionaire's playground, and we've got more and more satellites being launched and more and more hitting EoL with no decomissioning plan beyond leave it to quite literally fall out of the sky.
The Register 
Biting the hand that feeds IT
Copyright. All rights reserved © 1998–2023
