You know...
We can send 'em Elon... That'll set them back a bit.
Might be against the Geneva Convention though!
Chinese defence boffins have suggested aggressive countermeasures against SpaceX's Starlink satellite internet service. A paper in the February edition of Chinese journal Command and Control Simulation, titled "The impact of the 'Starlink' constellation on space situational awareness and countermeasures", was penned by …
Mention Elon or any other recent idiots like Putin, Hitler, Boris, Trump, Xi Jinping etc etc and you'll see down votes, a down vote is just a readers instant "comment", not necessarily a bad thing at all. Look on the bright side - down votes at least indicate that readers have seen your comment - they didn't just ignore us both (that's a potential prediction LOL).
@Version 1.0
I agree with your sentiment in general (have a vote), but you lumped too many people into the same category. I suspect that is where your downvotes came from. Some of those people wouldn't make lampshades out of human flesh. Some people are also just sick of seeing evidence of Godwin's law.
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NASA has been studying that problem since the 1960's - its referred to as the Kessler Syndrome and was used as the basis of the film Gravity. I don't think they have identified a critical number of satellites beyond which the problem will definitely occur (too many random factors), but two potentially major sources of debris that they are currently worried about is ESA's Envisat (8 tonnes of dead satellite in LEO) and Starlink; my guess is that they'll add the other mega-constellations to the list if/when they get tossed into orbit.
See https://en.wikipedia.org/wiki/Kessler_syndrome for more information.
As I understand it Starlink isn't a great threat as far as Kessler syndrome is concerned - the birds are flying low enough that the debris from falling apart machines, intentional or otherwise, will de-orbit in a reasonably short time due to atmospheric friction (which is part of the reason each Starlink satellite has a life of 5 years)
Willing to be wrong of course.
Kinetic energy is a bitch - if 2 objects collide the overall momentum must be preserved so the probable outcome is some fragments will be decelerated and their orbits will decay and they'll burn up but some fragments will be accelerated and climb into a higher orbit which will cause problems for other higher satellites which are less likely after a collision to decay and burn up.
Fragments can only get into a higher orbit if they are equipped with thrusters that can add energy to them when higher up.
Without thrusters, the orbit of the fragment will always intersect the elevation that the fragment had at the point of the original impact.
So what you get are not higher orbits, but more elliptical orbits. If a fragment gets into an orbit that reaches higher than the original satelite orbit, then the orbit of the fragment will also go lower. I suspect that at the heights where starlink flies, fragments that can reach high enough that they may endanger higher flying satelites, will also fly low enough that they will have half an orbit to do damage before they burn up in the atmosphere. Not zero risk, but much less risk than seen with higher flying satelites, and space is BIG.
they'll burn up but some fragments will be accelerated and climb into a higher orbit which will cause problems for other higher satellites which are less likely after a collision to decay and burn up.
Yes and no. Conservation of momentum applies, so something that was in a circular(ish) orbit may end up in a much more elliptical orbit, with higher apogee but much lower perigee. This could introduce debris to other - higher - orbital planes (on a temporary basis), which could induce kessler syndrome higher up, even though that debris will also circle down to a low perigee.
But the StarLink constellations are all in low enough orbit that even with some uncertainty around debris trajectories, the shells will self-clear within 5-10 years. Which is a major inconvenience to a lot of projects (science, comms, remote sensing, military, etc), but is also a relatively temporary blip in the scheme of things. It's not like being trapped on Earth for decades.
Its a long way from the Chinese and Russians doing ASAT demonstrations on satellites at 800+km which is going to stay up there for our lifetimes (and deorbit past/through the increasingly crowded shells at 3-500km).
if 2 objects collide the overall momentum must be preserved
I think energy is preserved, not momentum. And in case of collision, some of the kinetic energy is transformed into deformation energy (of the satellite). Take the extreme case if 2 satellites collide head-on.
Starlinks deorbit all of the time. I believe 253 have to date. It's not uncommon to find one about to deorbit if you check regularly. There is one about to fall into the Atlantic off the Argentinian coast north of the Falklands shortly.
https://satellitemap.space/
> Complete Hollywood make-believe
My reading of it was that most of the duration of the film was in fact a sort "life flashing before the eyes" dream as the Sandra Bullock character actually died not very far into the film. If so, definitely make-believe, but not quite as bad as the orbital mechanics that the dream itself depicted.
Starlink do publish the ephemerides for their constellation, available here - apparently updated every 6 hours or so. Login required.
Data is also available here which is obtained from Space-track.
So the PRC saying that they don't know where Starlink Satellites are is being economical with the truth (or someone is covertly saying something about their ability to find the information)
1. It's illegal to post incorrect information about your spacecraft
2. For a country like China is trivial do random checks of published information
would have been much bigger egg on face for both SpaceX and the US to be caught publishing false info than anything else, it's just not a way of thinking that the CCP is even capable at this point
> For a country like China is trivial do random checks of published information
For anything to do with checking published orbital data against reality, all China - or anyone else, even the US military - need do is ask around the astronomy community, especially the amateurs.
There are quite a lot of people looking up, many of whom are interested in Starlink satellites (even if that is only to get a clear view without any of the buggers in the shot).
It'd be pretty dumb to post fake orbital elements. It's not like they're hard to check.
Their concern is more that they don't know what those satellites are carrying, and there are so many that they're always overhead. Indeed, the whole network design requires that there always be at least one Starlink bird overhead at any given moment.
Reusable rockets do not convey a huge advantage, the costs of the landing infrastructure and the costs of refurbishing the parts and recertifying them are pretty close to the original build costs. Also the additional fuel needed for a controlled decent reduces the effective payload considerably.
Also no need to copy SpaceX, NASA worked out how to do it over 30 years ago and that information was openly published but apart from the shuttle they decided the payload reduction wasn't worth the ability to reuse.
>>Reusable rockets do not convey a huge advantage, the costs of the landing infrastructure and the costs of refurbishing the parts and recertifying them are pretty close to the original build costs
Really? I wonder why SpaceX decided that, commercially, reusable was the way to go.
That strikes me as a "commercially sensitive" and not surprising that they've not published cost breakdowns. After all, that would tell us all how much extra they make on re-use launches and might affect how much customers are prepared to pay. I think we can infer from the booster turnaround times that there's not a huge amount of refurbishment work going on. IIRC the fastest turnaround time was 21 days or so, which sounds reasonable for a thorough examination, replacement or whatever of any single use parts etc. ie far far less "refurb" than any Shuttle parts needed which strongly implies it far cheaper to re-use a booster than build and throw away a new one. I think they are averaging more than 4 flights per booster these days.
Without reusability the launching of huge constellations like Starlink isn't financially feasible. Europe is trying to put up a similar constellation but my guess is it will only consist of a few dozen satellites until they can figure out reusability (read: steal and copy SpaceX's design).
...I wonder why SpaceX decided that...
Because it looks cool.
Also if you're just lifting to LEO then the re-entry fuel requirements are not too onerous.
If you pay attention you'd notice that when SpaceX launch to higher orbits they discard the rocket just like everybody else.
Another issue is how many rockets you plan to use, if like SpaceX you destroy over 30 stacks trying to get the landing to work then you need to have at least 60 launches planned just to break even. Not many operators would consider 60+ launches from one design.
Very little was "destroyed" in trying to get reusability to work since what kept blowing up were used boosters. And now SpaceX have mastered reusability you can bet they'll be using it on far more than a double-digit number of launches.
The fact that SpaceX discard the first stage when they have to because they need the weight for fuel is irrelevant to the benefits of reusability when it is possible. WW2 fighter pilots were happy to destroy their engines if it meant getting away with their lives* – that doesn't mean it was SOP.
* Look up war emergency power.
WW2 fighter pilots were happy to destroy their engines if it meant getting away with their lives
I've always wondered about landing craft. War movies show them stopping in water, and the soldiers/marines wading off.
But my father recounts supervising sailors who couldn't swim in the immediate post-war period. When they thought the landing craft was sinking, they "broke the seals", put on full power, and landed well up the beach.
Why the downvotes - what in my post was factually wrong?
There can't be many Musk fanboys left, certainly not here.
Check SpaceX own data, they destroyed over 30 stacks some of them carried a small payload but not all, just to get the landing to work - it takes a lot of recycled launchers just to get to break-even over the cost of disposable launchers.
The thing is rocket science is complicated, while intuitively reusing rockets sounds like a good idea it is only in very specific circumstances:
1) you must have a lot of launches using the same design stack planned.
2) you can only lift to LEO in order to have enough fuel left to make a controlled decent.
Check SpaceX own data, they destroyed over 30 stacks some of them carried a small payload but not all, just to get the landing to work - it takes a lot of recycled launchers just to get to break-even over the cost of disposable launchers.
This was factually incorrect. Pretty much every F9 experimental landing was a paying revenue launch - including proper multi-tonne payloads like Dragon to ISS (CRS programme). There were some oddities like Orbcomm-OG2, which was rather lightweight. But that was because it was a Falcon1 contract and it was cheaper for SpaceX to launch on a (then-proven) F9 than manufacture a one-off Falcon 1 (which they'd abandoned at that point).
Whilst the R&D was by no means free, their testing regime was on "spent" rockets which otherwise would have been deliberately dumped at sea (like every other rocket).
1) you must have a lot of launches using the same design stack planned.
Yep. That is how most rocket companies work. Design one rocket, sell it as many times as possible. They've now launched something in the region of 205 missions using 79 first-stage boosters. Which is rather less than the 1:1 ratio of missions:boosters that everyone else manages. On paper, that ratio isn't as good as the Space Shuttle, but they're also not charging a billion dollars per launch, and they haven't killed anyone.
2) you can only lift to LEO in order to have enough fuel left to make a controlled decent.
This is less limiting that you might imagine, since Falcon9 is massively overpowered and a lot of people want to go to LEO (widely defined as anything <2,000km) anyway. Tom Mueller ended up getting a lot more power out of Merlin than they expected, with the result that F9 is predominantly volume-limited. You can't actually get up against the mass limits unless you're launching a tank of water, or trying to go to Mars. And people going beyond Earth orbit tend to have their own propulsion/kick stages and only want to get to GTO anyway. F9 has launched to GTO this year and recovered those stages.
Production capacity, supply chain and other factors could have been considered when the business decision was made to go reusable even if it costs more. Remember, cheaper is not always the best solution. Unless, of course, if you were in that board room when all this was discussed and you are in possession of some first hand information.
"Reusable rockets do not convey a huge advantage, the costs of the landing infrastructure and the costs of refurbishing the parts and recertifying them are pretty close to the original build costs. Also the additional fuel needed for a controlled decent reduces the effective payload considerably."
That was true for Shuttle but it's not true for Falcon 9. Asshat extraordinaire though Musk is, SpaceX has successfully knocked at least one zero off the cost of putting a kg into orbit and - as the story notes - manages a remarkable launch cadence that's coming close to 1/week on a fleet of around 10 reusable boosters and fairings, with a reliability that's close to beating the Soyuz/proton family. Even the man-rated Dragon edition is significantly cheaper and much more successful than the rival Boeing Starliner, which has yet to fly with a crew. The landing infrastructure for Falcon 9 is a concrete pad or a barge. It's not a vast expense.
The difference is that NASA never really iterated Shuttle's design, or Congress wouldn't fund it it, which amounts to the same thing. It flew pretty much the same experimental vehicle for 30 years. SpaceX rapidly iterated Falcon 9 from a disposable launcher into a system that reuses the most expensive parts.
Musk is an odious little twat, but that's no reason to deny the revolution in launcher cost and reusability that Falcon 9 has brought to the industry.
Musk is an odious little twat, but that's no reason to deny the revolution in launcher cost and reusability that Falcon 9 has brought to the industry.
This. Musk is a sociopath. But I hear people say "nothing he has produced is good", and they're factually wrong.
SpaceX has been a fire up the arse of the entire space industry (and they currently hold an effective monopoly on non-Russian launches since ArianeSpace are currently flapping around trying to work out how to make Ariane6 as good as the original Falcon9, whilst ULA aren't going to do more than 5-6 Vulcan launches a year unless Blue Origin decide to become a serious engineering firm at some point and manufacture their BE-4 engines in volumes better than "we've just about managed to cobble together two for you". China and India are options for some people, but don't have the cadence to be a regular/reliable partner).
And whilst I hold no particular love for Tesla, their (poorly-built cars with panel gaps the size of your fist) have likewise lit a fire under parts of the motor industry, and broken the chicken-egg problem of charging infrastructure by just going and doing it themselves. They mainstreamed EVs and that's no bad thing.
It's possible to separate out the person and the business. I have great admiration for SpaceX as a business, and will continue to do so - because they're doing what everybody else in the world has spent decades talking about but not actually doing.
I'm going to have to disagree with you there.
Nothing MUSK has produced is good.
Both companies have teams that exist purely to manage the twat's idiocy. They're successful in spite of him, not because of him.
OTOH, Twatter has no such team, and his incompetence (and now outright racism) are on full display.
Both companies have teams that exist purely to manage the twat's idiocy. They're successful in spite of him, not because of him.
Musk built those teams. He convinced Shotwell, Mueller and others to come start a rocket company that wasn't backed by old-space. Team-building was actually his strength as a CEO - finding the right people to answer his questions or fill the right seats in his company. But at some point he started drinking his own Kool-Aid, and this (declining) ability to get the right people in the right place seems to correlate with his falling performance as a CEO.
You're quite right, SpaceX is now successful because Shotwell is getting the work done in spite of Musk. But he recruited and built that team in the first place. That was the thing he was legitimately very good at.
"Shotwell is getting the work done in spite of Musk". LOOL. Somehow no Space X employee, or people who have written books on Space X (Eric Burger) have heard of this. Shotwell is a good executive, but most executives at top are very competent. Do you think tony bruno is any less competent?
Why did IBM never amounted to much, in spite of having the best "Phd" in the planet? Why could Google no make product like ChatGPT, which Open AI did (a Musk company).
Leadership matters. Of course you need very competent executives, but the without the vision and drive of the CEO, nothing would matter much.
Ya, denying reality is not easy. Musk has never failed in a venture, something very few CEO's can boast. Zip2, Paypal, Tesla, space X. Verdict for Boring & Neuralink is still out, we will know in next 5 years.
You mean to say all companies became No 1 in their segment "in spite" of Musk?
Truth = Reality. If you deny truth, you deny reality.
You're wrong on both counts. You seem to conveniently forget that the landing infrastructure can be reused many times. Also there's little refurbishing done by SpaceX (apart from cleaning off the soot, filling up the igniters with fluid and some basic checks) and absolutely no recertifying .
If NASA conveniently wrote it down for everyone to implement why is SpaceX the only company that has done so so far?
> If NASA conveniently wrote it down for everyone to implement why is SpaceX the only company that has done so so far?
Um, simply because the development costs were larger than any company felt like risking at the time? Particularly as the perceived "need" for launch capacity was, for a long time, satisfied by the various non-commercial launchers.
Then we just passed the point, as has happened with other products, that the perceptions about market potential versus costs, and simple belief in the sanity of the idea, tipped towards the "you know, with this much money upfront we could actually do this commercially".
At which point, we got multiple companies all working towards providing commercial launch capacity.
SpaceX managed to get the dosh from Musk, the advertising from Musk and enough people around who could actually do the job. The key thing being the dosh.
If it hadn't been SpaceX then it would have been someone else - although we may have had to wait a bit longer for the balance to tip even further towards commercialisation of space and/or someone else with a bucket of cash to come along.
> why is SpaceX the only company
Because they got the biggest skip load of readies
> that has done so so far
others are/will come along; some company or other has to first at anything, or that thing simply doesn't happen. Nothing much more than that gloriously trivial observation.
Plus a few trailer loads of lucre.
Eh? Some sources for these claims would be useful. A concrete barge costs beans. I’m pretty confident to have very recently read that spacex no longer even clean the ‘soot’ off their machinery before relaunch. Can I source the last? No. Too late to do the math on the reduced payload proposition but intuition suggests several rather short burns to land is trivial in comparison to launch.
CcP and PLA Did break into SpaceX and steal most of the source code but they forgot that MAssive projects have hideous tooling and integration requirements and simply stringing together if_then_else isn't going to cut it for even the start.
With out the scripts and tools a d People in the know how to configure build and execute you are stuck up sh*t creek without any clothes on.
Or maybe they're just too stupid to figure out what it all means.
I clearly remember the story of China copying Germany's maglev train and ending up with a design that barely worked because they'd changed dimensions of some of the parts (to make them fit their train). They didn't have a clue why the parts were designed they way they were. They just copied them verbatim.
That would be seen as an act of war. The early overflights of the USA by Russian satellites were allowed by the President as he realised that trying to do something about it would make space a no-go area for the USA. Since then, orbital space has been seen as free to any state that wishes to use it. If the Chinese were to actually destroy a Starlink satellite, and it could be proven, all hell would break loose as no satellite would be safe.
I don't think even the Chinese or Russians would be politically stupid enough to actually do anything about overflying satellites, they've got too much to lose.
I don't think even the Chinese or Russians would be politically stupid enough to actually do anything about overflying satellites, they've got too much to lose.
Or it could be one of those "nothing to lose" situations. Surveillance satellites over Russia or China suddenly go dark. Do you a) Start writing a strongly worded diplomatic note or b) Start alerting your/friendly forces to expect an invasion real soon now. Using anti-satellite weapons against someone else's satellites would seem a fairly good alarm indicator that things are about to get kinetic.
Alternatively, satellites might start experiencing a higher than expected failure rate, or become temporarily disabled as they pass over a nation's territory. If it's non-permanent, that would seem tempting to prevent spying. Or there's perhaps reasonable concern around a Western monopolisation of space with Spac-X, Amazon etc all currently planning to litter LEO with tens of thousands of satellites making it challenging for China to operate their own services, or the risk of collisions more likely.
Life seemed simpler when it was mostly geostationary satellites when nations were allocated their own slots ot manage roughly covering their own territories. Not exactly easy to do the same with low orbits and have satellites that can swerve to avoid airspace they're geo-fenced from.
They aren't looking at destroying them, they appear to have discounted that as a possibility. They are considering ways of making them stop working (while over China?) "to stop surveillance".
They know full well that Starlink doesn't do surveillance, and has no obvious plans to start doing surveillance; unlike existing commercial mapping sats such as the the Maxar constellation or the well known US government fleet owned by the NSA which definitely do; so that's not going to be their actual concern, it's a smokescreen.
From that one would have to infer that their actual concern would be Starlink providing unfettered internet access which is not subject to the Great Firewall of China and thus is not trackable by the CCP. For that to be a concern that would lead you to assume that they consider unfettered internet access to be an existential threat to their regime, which is telling as to how much support they think they actually have amongst their population versus the number of people who they think hate them.
Presumably they think that their police interrogating anybody who says anything that they don't like is keeping expressed dissent from being expressed rather than eliminating it.
And what makes you so sure that one of those tens of thousands satellites is not doing surveillance right now ? Also what makes you so sure this would not be done in the future when nobody pays attention ? It's not Starlink's job to do surveillance in the same way it's not the global telecoms job to intercept traffic for NSA and pals. All they have to do is to close their eyes and cover their ears and mouths.
And what makes you so sure that one of those tens of thousands satellites is not doing surveillance right now ?
This is a satellite designed to do surveillance:-
https://www.maxar.com/constellation
It's got a big thing where the camera sits, and a long bit with the lenses. Google "Focal Length" if your really interested but simplistically, a longer lens gives better magnification. If your shooting from orbit and you want decent resolution then your probably going to want a very long lens. (see also Hubble, which used mirrors etc from the Kh-11)
This is a picture of a Starlink satellite:-
https://news.sky.com/story/starlink-elon-musks-satellites-to-beam-high-speed-broadband-to-remote-areas-of-uk-in-government-trial-12759097
The lens on a satellite designed to do surveillance is several times the size of a starlink satellite.
"The early overflights of the USA by Russian satellites were allowed by the President" because no one had the capability to do anything about it. We didn't even have the capability (for a short while) to put our own satellite in orbit.
That's why everyone in the US lost their shit over Sputnik, and why the space race started.
I don't think China is worried about US surveillance with Starlink, but rather that there is an internet connection that bypass their great firewall. Elon Musk is crazy enough to sell internet service through Starlink satellites to people in China.
Is he? China is a big market for Tesla, and they do a lot of his manufacturing, and he's friends with a lot of authoritarian rulers who are friends with China. He's prepared to piss of the SEC but I've not seen him piss off the PRC (although I may have missed it - he says so much shit).
Yes - tungsten gives you the best result, with a really pointy tungsten carbide tip[1] to concentrate the impact, high melting point to keep it solid during re-entry and, being high density, you have a smaller launcher that can be tucked away in amongst the telecoms equipment.
Not that anyone has thought about this seriously, cough cough.
[1] some suggest a diamond tip, but simple carbon burns nicely, as well as having the problem of joining the tip and shaft securely; nah, just dope the tip of a single solid piece.
The "rods from God" studies the US military did assumed a tungsten rod roughly the size of a telephone pole. It would be pretty hard to hide a bundle of those inside a comms satellite. Such a rod would hit the ground going about Mach 10, with a kinetic energy equivalent to a bit over 11 tons of TNT. The problem is the rod itself weighs over 9 tons, so all the complexity really isn't gaining you much over conventional munitions.
If you try to go compact with it the yield gets worse really quickly. Also keep in mind you can't just drop them; each one needs a thruster to de-orbit it.
The current version of Starlink is a not particularly hardened Internet distribution tool. However, it was quickly found in Ukraine that while they might have got truckloads of terminals to ensure everyone had access to the Internet the military could repurpose them as low cost surveillance/reconnaissance tools. This has resulted in to changed to Starlink:-
-- One is the company cutting off service for those units used for offensive purposes (I've suggested it might be to avoid liability issues)
-- The other is discussions with the US MIC about making a Milspec version of the system
I'd guess that since the Russians have already got efficient countermeasures against Starlink 1 the Chinese are more interested in Starlink 2, the military version, because it does pose an actual threat to them.
(There's been no official announcement of anything but I've surmised this from articled in the Reg and elsewhere.)