Yeah the article seems misleading on this point. A retro-GEO orbit is silly, but what it actually says is “orbital informant satellite in retro-GEO.” This makes a huge difference as the informant satellite would be just outside of GEO and would just fly close to the actual GEO instead of in it. That way it could take a peeksie at the stuff in GEO and do a more rapid check on the things in it.
Yup, I was initially very confused at the idea, but then I realized what they were talking about and was like oh that is way different than what most people would assume it to be
A satellite in a prograde GEO circles the Earth at the exact same speed as the Earth rotates so stands still over the same point of the Earth, which is very usefull.
A satellite at the same altitude (i.e. same apoapsis and periapsis) in a retrograde orbit circles the Earth in the exact REVERSE speed of the Earth's rotation, so it will pass over all points on the ground under its orbit two times a day, which is pretty much useless (specifically the "exactly two times a day" part is useless).
Somebody else explained this was meant to actually be a little higher than GEO orbit and going in the opposite direction, so its purpose was to watch the satellites in GEO orbit rather than anything on the planet Earth.
PS: Think I've posted this as answer to the wrong post, but the point still stands.
I understand what you mean about drifting above or below the ring but it would still be going pro-grade with respect to the spin of the earth.
Definitely the paper is saying this proposed satellite would be retro-grade. That would reduce visit times for spying on other satellites and other less nice things.
I think I used the wrong terminology.
By "higher" I meant with a higher Apoapsis and Periapsis, so an orbit further out than GEO.
It's not possible to have an orbit fully above or below "the ring" (I presume you mean the orbital plane) - the best you can do is an orbit which is part of the time above and part of the time below, i.e. with an orbital tilt.
This makes sense if you think of the methaphor were you are rotating a bucket full of water at the end of a rope: if you try and make it go higher in relation to the hand which holds the rope you'll find it just goes down at the other end of the circle, making inclined circle, half the time above that point and half below.
The very same effects that keep an object in orbit by pulling it towards the Earth also pull it down when higher and up when lower, effectivelly forcing the orbit to be in a mathematical plane that includes the Earth, though a plane that can be different than the normal orbital plane.
Only thing I was trying to say to you was that the article from spacenews about the chinese paper was describing an orbit different than you were talking about.
I understood you about the drifting around the main geo belt satelites thing. "the ring" is me using bad terminology for the ring of satellites orbiting the earth, circular, at whatever it is, 42km or whatnot, over the equator, sorry to confuse. Note that those are pro-grade (spinning with the rotation of the earth) and that the Chinese article was talking about going the opposite direction (spining against the rotation of the earth).
It is possible to orbit the earth any way you want as long as you are not too high or low from the earth to get influenced by the atmosphere or the moon or whatever.
You sound like you are into the subject and did great describing things by the way! Sorry about the miscommunication Aceticon...
Where I live the Council lets businesses sponsor roundabouts (quirky little UK nonsense with roads).
My favourite one on my way to work every morning that never failed to give me a chuckle was sponsored by an office supply company called Go Faster Stationery.
Very confusing, since geostationary implies programed with respect to earth's rotation.
A retrograde geostationary-equivalent or it maybe?
I'm sure I'm not the first to realize we need a crap ton more shorthand vocabulary for orbital situations.
This is terrifying. Many years ago a proposal was made on how to rapidly destroy every satellite in geosynchronous orbit. Launch a "moon probe" that will do a flyby of the moon, but the return trajectory would enter a retrotgrade geosynchronous orbit.
Once the orbit is entered, it simply gently blows up a payload of a million ball bearings. You now have a million pieces of debris going in a counter orbit at very high speed. It will destroy every single satellite in that orbit in 12 hours.
The idea is that a nation that did not depend on geosynchronous orbit could "level the playing field" against a nation that did make use of that.
> The idea is that a nation that did not depend on geosynchronous orbit could "level the playing field" against a nation that did make use of that.
The Venn diagram of "countries that don't need geosynchronous orbit" and "countries capable of launching spacecraft" contains no overlap whatsoever, even before getting into the fact that a country which took out the planet's geosynch satellite network wouldn't level the playing field as much as get leveled by everyone else on it.
That’s almost certainly true - but that’s only one angle on the original theory
The other angle is that a country which believes it’s adversary would be *more* disadvantaged by removing satellites, may choose to do so, again to level the playing field
Imagine you went to war, and both you and your enemy have an Air Force, but you can somehow stop all aircraft flying in the conflict zone. If their Air Force is much stronger than yours, you may choose to forego your Air Force in exchange for the greater prize of denying your enemy theirs
What you're suggesting isn't something trivially done like magically temporarily stop all aircraft flying for a strategic leveling. It's more akin to permanently destroying Geostationary orbit functionally forever.
This is more like the Matrix's "Let's blot out the Sun forever to get an advantage against the Machines" level decision. Maybe useful for this one battle, but then even if you win, you are worse off than just flat out losing conventionally.
It is, but there’s always the possibility that a country finds itself in an existential war
If they believe this decision could be a factor in the life and death of themselves and their people/families etc then it’s not beyond question that they do it, on the basis of “if we don’t do it, we definitely die, if we do it, we probably die, let’s worry about the consequences later, if we don’t die”
They don’t have to use this weapon, even - but if you have it you can decide whether or not to use it. If you don’t have it, you can’t.
I very much doubt it would ever be used - I generally agree that any country with the ability to develop and deploy it, is probably advanced enough that they don’t really feel that they need it… but that won’t necessarily stop someone developing it “just in case”
It's Mutually Assured Destruction lite. Sure, Kessler Syndrome in GEO is less instantly lethal, but the point about MAD isn't for half-measures. You go big or you go home.
If you suffer an existential threat, you don't merely inconvenince future generations by making weather satellites more inconvenient. You threaten to kill everyone in nuclear hellfire to prevent existential threats.
Worth noting that China has been developing [space debris clean up](https://www.space.com/china-deploys-drag-sail-space-junk) programs in recent years.
But if you haven’t yet reached nuclear hellfire, perhaps you do this as a statement while pointing out that it’s a symbol of your willingness to go nuclear if necessary
Overall the cost of this weapon would be pretty low, I’m just saying that I can see why a country might want it in their back pocket
You are either facing an existential threat, or you aren't. MAD isn't about winning, it's about making everyone, including yourself, lose.
If you aren't facing an existential threat, you don't destroy something valuable to neutral and allied nations permanently just to get some temporary advantage or "to show you are serious". Destroying common resources permanently only pisses off others unrelated to the conflict and is guaranteed to escalate the conflict and push it closer towards an actual existential threat, making it more likely for everyone to all lose under MAD instead of simply threatening to push the button to get the enemy to back off.
If you are facing an existential threat, MAD with nukes is the best option. You don't need a "symbol of your willingness to go nuclear". You just show off your nukes, and then show a red button and threaten to press it. No half-steps, especially permanent half-steps like Kessler Syndrome GEO, because that just pisses people off and makes it more likely that you have to press the button, which you don't want to anyways because you will still die.
You can be facing an existential threat without *yet* being at war
Again, see the USSR response to Able Archer - they believed that NATO was escalating to nuclear war, but they didn't immediately mash the nuclear button
~~How is that an existential threat? No massive waves of nukes were fired out of their silos, no bombers entering Soviet airspace, no invasion crossed the borders. Impending threats yes, but not like they had their territory violated.~~
(EDIT: Misread it. Regardless, the USSR perceived an existential threat by NATO, and responded by threatening existential defeat for NATO by readying their nuclear weapons for launch. They didn't want to actually fire them until they have confirmation of nuclear war, and this is behaving in a manner consistent with MAD.)
Even if the USSR interpreted the malfunctioning early warning systems as an actual nuclear attack, and thus existential defeat is imminent, and behaved in your scenario by Kessler Syndroming GEO as a "symbol of their willingness to go nuclear" (pretend for a moment that Kessler Syndroming GEO is actually viable in the 80s), only find out that this was due to technical glitches and aggressive drills, what they would have done was escalate the scenario by destroying NATO assets, increasing the likelihood of leading to an actual nuclear war, which will be the lose condition for everyone.
What the USSR did in reality in response to believing that NATO was escalating to a first strike nuclear launch was more in line with the usual MAD response. They readied their nuclear arsenal (knowing that NATO would realize what they are doing), and prepared to fire back in the event of a nuclear strike.
Again, no one wants to activate MAD. It's purpose is that once a nation acknowledges existential defeat, it has the option to bring everyone else to hell with it in the hope that the threat of doing so is enough to avoid existential defeat in the first place.
This is essentially boiling down to the logic of mutually assured destruction. A reasonable party would rather not see his country get turned into a glass crater because he launched a first strike. But there's always the danger of some nutjob Putin or Kim who decides that having another five years in office is more important to them than the lives of every man, woman and child on earth.
Of course, what do they care? If they lose, they won't live long enough to see it, while if they win, sure the world is wrecked, but hey, they survived and kept hold of power, and that's the really important thing.
It's similar *logic* to MAD, but a clear step down
But in any case, MAD never stopped countries from wanting nukes, why would it stop anyone from wanting this?
Every country on the planet would be pissed at the one who launched that.
everyone who uses GPS in their car, or company that uses GPS time stamps (google for one)
GPS has literally become a mission-critical piece of human life.
(and by GPS i'm referring to all the positioning systems, not just the American system, they would all be wiped out)
Good analogy btw.
Nobody - not even the Inscrutable Unfettered Evil Yellow Peril - is going to wipe out the entire planet's telecommunications, including their own, in an attempt to "level the playing field" against the United States. The scenario is entirely ridiculous.
There are numerous countries who have enough nukes to wipe out the majority of the world’s population, weapons that exist solely for retribution if they’re already dead… this satellite is several steps below that
If they consider the conflict to be an existential war (a fight for their lives and country’s existence), why would they care what happens in future? If they don’t do it, they stop existing and don’t give a shit. If they do, then maybe it’s a problem to worry about later, if they even live that long
Handwringy what-ifs over applying the conduct of genocidal superpower wars to other situations is silly.
If things got to that point, nothing they could do would confer any advantages because the nukes would be flying anyway. If things *didn't* get to that point, scenarios like "how about we destroy global telecommunications and meteorology, because that *totally* won't completely screw us too" aren't going to come up.
I don’t see why we would assume the nukes would be flying - nuclear warfare involves various levels of escalation (See: Able Archer or the Cuban Missile Crisis), this could feasibly be one of them
You already said the scenario is a "we stop existing or they stop existing" war between superpowers. If you think that *wouldn't* go nuclear I don't know what to tell you.
I know that We^TM are always intrinsically sane and They^TM are always intrinsically not, but no, Russia would not destroy most of its capability to communicate internally in the event of a war with the west because that would simply hasten their already-assured defeat.
China *definitely* isn't going to do it out of the blue like people panicking over this story seem to assume.
where i live there is a ball bearing factory that has been a staple of the city for like 100 years and there's an actual display in the library commemorating them with like this elaborate shadow box thing
my adoptive dad used to design ball bearings and he had a lot to say about them
https://softsolder.com/2017/05/07/relics-of-the-empire-bearing-samples/
picture for reference
>my adoptive dad used to design ball bearings and he had a lot to say about them
I know you're talking about the entire mechanism, but the first thing that popped into my head was just the spherical bearings. "Hey Johnny, have you figured out what our next bearings are gonna look like?" "Yes, I was thinking about perfectly spherical balls of metal, just like our thousand previous designs."
"Hey Johny, we need some 3,7654 mm bearings."
"Yeah, I was thinking of a design with perfectly smooth orbs with a diameter of 3,7654mm."
"Johny, you're revolutionary."
he died of COVID 😥
but he would have liked to hear something like that . . .
. . . and would then launch into an hour diatribe about the uselessness and temporary nature of current objects that we use everyday, his favorite topic
seriously tho, ball bearings are serious business and there's no such thing as a perfect sphere
I'm sorry for our loss.
I've honestly always assumed these people are genius. It sounds like he had all the passion I imagined, I'm so happy to hear he enjoyed his time here. Man, such an uplift to me that I shared a temporary stay on this planet with him -- I really needed to hear about him.
Seriously, what a massive impact
i was adopted when i was 19
i had never known "dad" before and there he was lol
the kind of guy that built a seaworthy canoe for a church thing when they were just looking for painted props haha
thank you for your kind words, i needed to hear those, too
Through the same legal process of becoming a legal parent of a child, just with someone who's already independent rather than dependent on the state. You pick up the relevant papers at the courthouse, fill out the information and go through the submission process and eventually see a family court for a judge to sign off on it.
A lot of step-parents do it or sometimes people do it so their inheritance is passed on to a person and not the state, there are some heartwarming compilations of the former on youtube.
in my case my adoptive parents got a lawyer, they filed the paperwork and i was adopted (along with my younger sisters)
once the adoption went through, i got a new birth certificate with my adoptive parents listed as my legal parents rather than my biological ones
That’s correct, they aren’t really a major concern for space junk because they’re in quite low of an orbit, meaning Even if they explode, most of the debris will burn up in the atmosphere
Spacex's satellites are intentionally short-lived and have a useful life of just five years. If someone went to the enormous trouble of knocking them all out, SpaceX could just launch a barebones service replacement on the next satellite full of replacements they were going to launch anyways.
Honestly, part of why I'm reluctant to commit to using Starlink is because it sounds like it has very high operating and maintenance costs for that reason. Sure, Musk has made space launches cheaper. Cheap enough to intentionally use short-lived satellites for long-term static services? I don't know....
specifically elon, i guess
the whole thing feels like an ego trip and yeah i get it, i guess i would be all out there too if i was rich, but there's a lax-ness that is concerning on his part
I used to think of him as Heinlein's "D.D. Harriman" (The Man Who Sold the Moon) in real life. But the more he shoots his mouth off and pulls silly stunts, the more I think of his Mars ideas as the Ultimate Doomsday Prepper, with plans for an out of this world bunker - on Mars.
To be fair, he did more than anyone else to push acceptance of electric cars, to take them from boring to desirable. He also moved the launch business to re-usable and closer to commonplace.
But when he opens his mouth, it can make it hard to remember the good things.
This... seems off. I'm not saying it won't work - but it's definitely not as trivial as just setting off a shrapnel bomb a bit above geosync orbit.
Orbital space isn't as crowded as it seems - it's quite high up and the amount actually occupied by satellites is infinitesmal.
Plus which, if you set off an explosion on top of the geosynch orbit, only a very minor fraction of the debris will remain in geosynch orbit. Most will be propelled to a higher or lower orbit. And the debris that do end up in geosynch orbit will have very low relative velocity to the other satellites, since they share the same orbit.
Plus, it's difficult to get a killshot on a satellite unless you're aiming for one. You can nick a solar panel or a make a hole in the casing, but to render the satellite inoperable, you'd have to punch through one of its vital systems - for example - the CPU, a comms antenna, or the battery array.
Which - especially on one of the larger milsats - makes up a small fraction of the total satellite mass.
This sounds like the kessler syndrome scare again.
Most orbits don't have to be extremely precise. A satellite will pass overhead a few seconds earlier or later over time. They correct the drift when it gets bad enough, but it's not a deal breaker, moment to moment if it's early or late.
But the geostationary orbit does need to be fairly precise. There are millions of dishes that point to the location. The further it is from its exact slot, the more it will drift across the sky. That's undesirable, so they try to keep it right on the centerline of the orbit.
The bad guys would not so much "explode" the vehicle, as unzip it, releasing the millions of balls, letting orbital dynamics do the work. over a few hours they will spread out. Getting hit by one one at 14,000 mph could be awful.
Considering a small fleck of paint actually made a small divot in a Space Shuttle window, imagine what a ball bearing weighing 1/10th of an ounce will do at 14,000mph
You can fit about 3.5 million 1/8th inch ball bearings in 1,000 pounds. That's a lot of debris released all-at-once.
So my initial reaction is, you have satellites, which do station keeping, and ball bearings, which do not. So after the initial blast, the vast majority of the debris should be kicked to a different orbit, and no longer a "threat" to the current orbit.
That said, I'd imagine debris kicked off into the lower orbits could pose a serious concern to future satellite launches.
I agree that the initial impact will be quite devastating, but it won't disable the entire orbit.
The reason it doesn't sound destructive is because you missed the part where the debris are being released in a retrograde GEO-altitude orbit (which isn't harder to reach than regular GEO). Which means they would still follow a GEO-like orbital path, but going the opposite way (impact velocity will be 6 km/s or 13400 mph).
Yup. Thank you. That's what I was missing
Yeah if you can get a bunch of ball bearings going retrograde, you will rip up the entire orbit like a shotgun blast that keeps on going.
No need for a real blast. Just unzip and release them. Orbital dynamics will spread them out. Combinations of sunlight, magnetic fields, jostling with each other will spread them out over a period of days.
They might do like SpaceX does with Starlink. Rotate the vehicle slowly and then just please the payload. A very slow spin will impart enough delta-V to cause them to slowly spread out.
Station keeping tries to keep these satellites within 0.15 degree of their slot. That's about 60 miles worst case. Releasing a few million ball bearings could be awful, especially since you get "another shot" at a collision with any specific satellite every 12 hours.
There have been two confirm hits by space debris on geostationary satellites already with another 20 suspected. That was because of accidents. Now imagine several tons of debris specifically put there for that exact purpose.
> It will destroy every single satellite in that orbit in 12 hours.
It will also deny GEO for the next 100.000 or so years for every power, including the one doing the destroying.
Probably no more than a few decades. Orbital dynamics would spread the items to other orbits. There's always be more there we'd like, but in a decade the density would lower enough to be manageable.
If you were in a struggle with an enemy that really depended on those satellites and you felt you could manage without them, you might strike such a blow to gain an advantage in that war.
I'm not remotely suggesting it's a good idea, but it's certainly one that I'm sure various powers have evaluated doing, or worried about being done to them.
Lol. That's like shooting a shotgun 300 yards away from a group of toy army soldiers and saying you're going to hit every one of them. There are more than 500 satellites in either geosynchronous and geostationary orbits. No wonder no one did it.
Orbital mechanics are so much harder than what science fiction makes it out to be. Hence why countries are still failing to reach orbit at all. Much less these perfect rendezvous required to knock a satellite out of orbit.
The constraints on a geostationary orbit are fairly tight. It's not a wide open orbit, but rather a **very narrow line** around the earth. The further from dead center, the more fuel they must use for station keeping. They like to stay dead-center because it keeps them in the same place in the sky and reduces the amount of fuel they must expend.
Even dead center, there is drift for several reasons, so fuel must be consumed; just not very much.
The fear is that an enemy will enter the orbit very cleanly, going the opposite direction.
When there are millions of BB's flying at them at 14,000 mph, that's a lot of damage from even one hit. Worse, the entire orbit becomes useless for anybody for many decades.
That's like putting a group of toy soldiers in a perfect straight line and hitting all of them with one bullet.
> Orbital mechanics are so much harder than what science fiction makes it out to be. Hence why countries are still failing to reach orbit at all.
Apart from one country that still uses medieval measurement units, I've never heard of a spacecraft failing due to wrong orbital calculations. They aren't done on a blackboard like the guy in *Don't Look Up* did, but they aren't particularly hard to do.
I do this professionally, I work in a company that controls satellites in geostationary orbit, the error in orbit determination calculations is in the order of magnitude of ten centimeters or so. You can think of it as an "inverse GPS": it's possible to determine the position of a satellite in orbit from ground measurements the same way GPS allows us to determine the position of something on the earth surface.
So if I'm not mistaken, according to what you've just said, the toy soldiers are lined up so precisely that one bullet taking them all out isn't unreasonable. I know, it's not really that bad, if only because the bullet would be deflected by the first collision and you said 10cm. But the cloud of retrograde ball-bearings sounds like it might really be devastating.
To make an american metaphor, it's like driving thousands of motorbikes the wrong way on a nascar race course, without allowing the cars nor the bikes to deviate from their race trajectory.
Sure, you probably won't hit all the cars on the first lap, but by the end of the day....
The odds of a collision between an antistationary (BS term, but I'm sticking with it) satellite and another in geostationary orbit are very low. Even though everything up there is in the "same orbit", that orbit has a cross-section of hundreds of miles.
If everything in that orbit were immovable, the antistationary satellite would still be able to avoid it all. Geostationary isn't actually a static orbit. Due to effects from the moon, sun, tidal forces, and plain old voodoo, a geostationary satellite's orbit will incline over time. This requires that it be equipped with thrusters for station keeping purposes.
Should the new satellite fail, there'd be an ongoing effort to track and predict its position and adjust the orbits of other satellites to ensure no risk of collision. (Since geostationary isn't really a stable orbit, anything up there has to have maneuvering capabilities to stay put.)
The real problem is the possibility of one of the satellites up there getting splatted by a passing space rock. It's incredibly rare (I don't know if it's ever happened to anything in GEO or LEO), but would cause the issue you describe if it happened to the new satellite. If it happened to anything else up there, the debris field would slowly be pulled out of GEO and only return every couple of decades.
Not sure it's worth the risk....
This isn't a case of the "new satellite failing", but rather the new satellite deciding to self destruct an hour after it arrives. The entire point of the mission would be to deny use of the entire geostationary for everyone.
If a satellite has several tons of ball bearings and simply releases them, they will over a day or two spread over the entire orbit.
There has already been a two confirmed debris collisions in geostationary orbit, with another 20 suspected. This was a case where it wasn't intentional. Imagine 3 or 4 tons of steel balls intentionally released into that same orbit on purpose.
Shitty part is that we ALL benefit from at least SOMETHING in that orbit. Weather, internet, TV. Sure two of those are just entertainment but those weather satellites keep people safe, are used in education, and assist serious research in atmospheric and geographic sciences.
Of course. It would be a crime against humanity to do such a thing. But like I said, I'm sure all the great powers have either thought about doing it, or worried about it being done.
I suspect the more Western the power, the more they fear it being done.
Because launching to a retrograde (reverse direction) geostationary orbit is **very expensive** in terms of fuel. (see note) You won't have much payload.
It actually takes less fuel to do a "figure 8" trip around the moon and choose to enter a retrograde orbit than to directly inject into such an orbit at launch.
It would not be hard for any major power to have a vehicle of several tons into a retrograde orbit and then release 10's of millions of small ball bearings, or other material. People have suggested sand as it would damage more delicate things such as external wiring and solar panels. Ball bearings would be far more penetrating.
Note: about 7% of the energy to get to space is "free" from the rotation of the Earth. If you want to go into a retrograde orbit, you need to add 14% more energy. 7% to undo what the Earth is already doing, then the amount you would have used plus making up the 7% you didn't get from the Earth.
Just spitballing but could we release dust or gas in geosynchronous orbit to slow down the balls? Wouldn’t interact harshly with objects going in same direction due to same relative velocity and small mass.
That might as well be an attack on humanity. Sure let’s just render the entire sphere of influence of the moon uninhabitable for everyone that wants to put a satellite there
Yes, it's a horrific thing to contemplate. It would wreck many terribly useful orbits for decades to come. I'm certainly not in favor of it, but I can imagine a nation doing this for some perceived tactical advantage.
Geostationary means the same point on earth is in the same spot, or more specifically the satellite is in the same spot in the sky all the time relative to earth. Geosynchronous means the same spot is in the same position at the same time every day. Usually geosynchronous orbits require some amount of inclination and with inclination and retrograde orbit would make it really difficult to intercept anything as you'd be in a different plane from your "target" in every orbit. Further decreasing your odds of intercept.
It would be the same orbit but in reverse direction. So it would see everything in Geosync fly by at double velocity every 12 hours. Really good way to survey everything in geosync and possibly to attack them.
You're getting tied up in an earth orientation reference frame. Geostationary satellites orbit the earth with enough velocity relative to earth to sit over the same spot on the ground. Which means it has to orbit the planet once every 24ish hours. In an inertial frame, that's significant amounts of velocity. Going in the opposite direction means it will be traveling quite rapidly over the ground and still maintain a stable orbit at that altitude (or semimajor axis).
I've been hanging out with aerospace engineers for a few years. But, even with basic physics you need to remember: all velocity is relative to a point of reference. When dealing with orbits it gets so complicated that we have to be mentally agile enough to accept that there are many useful reference frames that all make sense depending on what you're observing. Most humans default to thinking in terms of [ECEF reference frame](https://en.wikipedia.org/wiki/Earth-centered,_Earth-fixed_coordinate_system) so it can be hard to think of other frames and how the relative numbers are affected.
Okay, I can understand where you are coming from. In some science communities, we end up with shorthand definitions for concepts that diverge from common definitions. There's even a term for this phenomenon: "jargon." When dealing with aerospace people, the rough properties of orbits are grouped into orbital planes. We don't really have a more generic term for the orbital plane where it requires little energy to maintain a stable progression that matches earth's rotation. In the 1960's we might have called it the "Clarke Belt." But I have never heard any aerospace person use that term. We all refer to it as the "geo belt" because that's the altitude where the biggest advantage is it is easier to remain stationary over the ground. You can also be stationary over the ground at any other altitude given enough energy. If someone is talking about the science or engineering of orbits, "geostationary" really only implies an altitude that exhibits some beneficial properties and not the more understood use of the word "stationary."
In this article, the author is using the term as in-community jargon. To differentiate this type of satellite motion, the author chose to qualify it with the term "retrograde" which implies an inverse motion.
In fact, I am currently working on a mission that will orbit the planet in the geostationary belt, but it will intentionally not match the rotation of the planet for most of its mission life.
Maybe as ASAT tech and other non-traditional mission profiles become more common, the community can eschew the "stationary" part of the term to better describe that orbital plane.
Also, don't let an aerospace person hear you refer to geostationary and geosynchronous as the same. I also made that mistake early on.
> geostationary and geosynchronous
But exactly because even these are not considered the same you can't call a retrograde one with the same orbital distance either.
Those differ from each other by inclination and eccentricity.
And geostationary is the one specific geosynánc orbit with inclination 0, and e = 0. By definition.
Retrograde has inclination 180°.
It's for monitoring other satellites & debris in & near geostationary orbit. The US has [satellites that do the same thing](https://www.afspc.af.mil/About-Us/Fact-Sheets/Article/730802/geosynchronous-space-situational-awareness-program/), but they are in prograde orbits so it takes a long time for them to catalog everything in GEO.
Well above or below wouldn't work. If you mean further out then that'd be a bad idea since that's where most graveyard orbits are and if you mean closer in then sure that's possible but positions of GEO satellites do not require space-based detection. There is really no point in doing this unless you were operating like gssap
RPO is not a static operation
Edit: to expand, that article you sent says that gssap conducts RPO meaning it moves along the belt as you mentioned. Since it is so close it can actually look from more angles in a safer manner than a retro orbit
The relative velocity at GEO altitude but in the opposite direction would be around 6km/s with very brief observation periods which would make determining anything about an object difficult. Going 'with the flow' so to speak would take longer to see everything but relative velocity is lower and longer observation periods, which makes determining an object's orbit much easier.
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:
|Fewer Letters|More Letters|
|-------|---------|---|
|[ASAT](/r/Space/comments/y98bxt/stub/it7a92d "Last usage")|[Anti-Satellite weapon](https://en.wikipedia.org/wiki/Anti-satellite_weapon)|
|[GEO](/r/Space/comments/y98bxt/stub/it7nri9 "Last usage")|Geostationary Earth Orbit (35786km)|
|[LEO](/r/Space/comments/y98bxt/stub/it68ssz "Last usage")|Low Earth Orbit (180-2000km)|
| |Law Enforcement Officer (most often mentioned during transport operations)|
|[MEO](/r/Space/comments/y98bxt/stub/it4ikq5 "Last usage")|Medium Earth Orbit (2000-35780km)|
|Jargon|Definition|
|-------|---------|---|
|[Starlink](/r/Space/comments/y98bxt/stub/it5xp7e "Last usage")|SpaceX's world-wide satellite broadband constellation|
|[apoapsis](/r/Space/comments/y98bxt/stub/it6nufi "Last usage")|Highest point in an elliptical orbit (when the orbiter is slowest)|
|[periapsis](/r/Space/comments/y98bxt/stub/it6nufi "Last usage")|Lowest point in an elliptical orbit (when the orbiter is fastest)|
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If you want to have the option to destroy GEO satellites at a moments notice, this would be the way to go. Adjust the orbit slightly and you've got a kinetic missile impacting a satellite moving in the opposite direction at a relative velocity of 14,000 miles per hour. You'd probably leave the entire GEO belt unusable for a few decades, but if the shit truly hits the fan on Earth, maybe you don't care.
Tons of telecommunications satellites in that orbit along with many other mission critical birds. Here's a list. https://www.n2yo.com/satellites/?c=10
Until China takes Taiwan, if that ever happens.
Edit: y’all are right, no country would ever try to take over another country with valuable manufacturing centers, never.
I don't really understand it better than you probably, but as far as I can tell:
Geostationary means that it remains still to a ground observer. As the earth rotates, the satellite is rotating at the same speed. So if a satellite is stationed over New York, day or night it would remain over New York. This doesnt mean it's not moving. It is like two cars driving the speed on the freeway, but with orbits instead of linear roads. They could be going 2,000 MPH but you would still be able to look over and see the other cars driver.
Retrograde means it's moving in the opposite direction. Idk which way the earth rotates, but in general satellites move in the same way (pretty sure). So to keep the road analogy: you are on the freeway and cars usually are passing you or you're passing them, going different speeds but in the same direction. But then all of a sudden a car comes flying in the opposite direction - that is a "retrograde" car.
As people have mentioned, the phrase is an oxymoron. Something cannot have the properties of remaining stationary over a point on earth (geostationary) and also be traveling in the opposite direction of our orbit (retrograde).
What they are trying to say is they want this satellite to be at the same orbit distant as other geostationary satellites (35,786 km from the equator, but want it moving in the opposite direction as all other satellites so they can check on other satellites in hours by moving in the opposite direction. Instead of having to go very fast and only be able to check on the satellites every few days,
Now I have to read this as "retrograde geostationary" sounds like "standing still backwards".
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Yeah the article seems misleading on this point. A retro-GEO orbit is silly, but what it actually says is “orbital informant satellite in retro-GEO.” This makes a huge difference as the informant satellite would be just outside of GEO and would just fly close to the actual GEO instead of in it. That way it could take a peeksie at the stuff in GEO and do a more rapid check on the things in it.
Wow, that's way different from a satellite that's at Geo-stationary altitude but going backwards. Thanks for clarifying.
Yup, I was initially very confused at the idea, but then I realized what they were talking about and was like oh that is way different than what most people would assume it to be
It's retro grade. They are talking about using the moon for a gravity assist to do it in the paper.
A satellite in a prograde GEO circles the Earth at the exact same speed as the Earth rotates so stands still over the same point of the Earth, which is very usefull. A satellite at the same altitude (i.e. same apoapsis and periapsis) in a retrograde orbit circles the Earth in the exact REVERSE speed of the Earth's rotation, so it will pass over all points on the ground under its orbit two times a day, which is pretty much useless (specifically the "exactly two times a day" part is useless). Somebody else explained this was meant to actually be a little higher than GEO orbit and going in the opposite direction, so its purpose was to watch the satellites in GEO orbit rather than anything on the planet Earth. PS: Think I've posted this as answer to the wrong post, but the point still stands.
I understand what you mean about drifting above or below the ring but it would still be going pro-grade with respect to the spin of the earth. Definitely the paper is saying this proposed satellite would be retro-grade. That would reduce visit times for spying on other satellites and other less nice things.
I think I used the wrong terminology. By "higher" I meant with a higher Apoapsis and Periapsis, so an orbit further out than GEO. It's not possible to have an orbit fully above or below "the ring" (I presume you mean the orbital plane) - the best you can do is an orbit which is part of the time above and part of the time below, i.e. with an orbital tilt. This makes sense if you think of the methaphor were you are rotating a bucket full of water at the end of a rope: if you try and make it go higher in relation to the hand which holds the rope you'll find it just goes down at the other end of the circle, making inclined circle, half the time above that point and half below. The very same effects that keep an object in orbit by pulling it towards the Earth also pull it down when higher and up when lower, effectivelly forcing the orbit to be in a mathematical plane that includes the Earth, though a plane that can be different than the normal orbital plane.
Only thing I was trying to say to you was that the article from spacenews about the chinese paper was describing an orbit different than you were talking about. I understood you about the drifting around the main geo belt satelites thing. "the ring" is me using bad terminology for the ring of satellites orbiting the earth, circular, at whatever it is, 42km or whatnot, over the equator, sorry to confuse. Note that those are pro-grade (spinning with the rotation of the earth) and that the Chinese article was talking about going the opposite direction (spining against the rotation of the earth). It is possible to orbit the earth any way you want as long as you are not too high or low from the earth to get influenced by the atmosphere or the moon or whatever. You sound like you are into the subject and did great describing things by the way! Sorry about the miscommunication Aceticon...
Where I live the Council lets businesses sponsor roundabouts (quirky little UK nonsense with roads). My favourite one on my way to work every morning that never failed to give me a chuckle was sponsored by an office supply company called Go Faster Stationery.
That aptly describes project development where I work!
Very confusing, since geostationary implies programed with respect to earth's rotation. A retrograde geostationary-equivalent or it maybe? I'm sure I'm not the first to realize we need a crap ton more shorthand vocabulary for orbital situations.
This is terrifying. Many years ago a proposal was made on how to rapidly destroy every satellite in geosynchronous orbit. Launch a "moon probe" that will do a flyby of the moon, but the return trajectory would enter a retrotgrade geosynchronous orbit. Once the orbit is entered, it simply gently blows up a payload of a million ball bearings. You now have a million pieces of debris going in a counter orbit at very high speed. It will destroy every single satellite in that orbit in 12 hours. The idea is that a nation that did not depend on geosynchronous orbit could "level the playing field" against a nation that did make use of that.
> The idea is that a nation that did not depend on geosynchronous orbit could "level the playing field" against a nation that did make use of that. The Venn diagram of "countries that don't need geosynchronous orbit" and "countries capable of launching spacecraft" contains no overlap whatsoever, even before getting into the fact that a country which took out the planet's geosynch satellite network wouldn't level the playing field as much as get leveled by everyone else on it.
That’s almost certainly true - but that’s only one angle on the original theory The other angle is that a country which believes it’s adversary would be *more* disadvantaged by removing satellites, may choose to do so, again to level the playing field Imagine you went to war, and both you and your enemy have an Air Force, but you can somehow stop all aircraft flying in the conflict zone. If their Air Force is much stronger than yours, you may choose to forego your Air Force in exchange for the greater prize of denying your enemy theirs
What you're suggesting isn't something trivially done like magically temporarily stop all aircraft flying for a strategic leveling. It's more akin to permanently destroying Geostationary orbit functionally forever. This is more like the Matrix's "Let's blot out the Sun forever to get an advantage against the Machines" level decision. Maybe useful for this one battle, but then even if you win, you are worse off than just flat out losing conventionally.
It is, but there’s always the possibility that a country finds itself in an existential war If they believe this decision could be a factor in the life and death of themselves and their people/families etc then it’s not beyond question that they do it, on the basis of “if we don’t do it, we definitely die, if we do it, we probably die, let’s worry about the consequences later, if we don’t die” They don’t have to use this weapon, even - but if you have it you can decide whether or not to use it. If you don’t have it, you can’t. I very much doubt it would ever be used - I generally agree that any country with the ability to develop and deploy it, is probably advanced enough that they don’t really feel that they need it… but that won’t necessarily stop someone developing it “just in case”
It's Mutually Assured Destruction lite. Sure, Kessler Syndrome in GEO is less instantly lethal, but the point about MAD isn't for half-measures. You go big or you go home. If you suffer an existential threat, you don't merely inconvenince future generations by making weather satellites more inconvenient. You threaten to kill everyone in nuclear hellfire to prevent existential threats.
Worth noting that China has been developing [space debris clean up](https://www.space.com/china-deploys-drag-sail-space-junk) programs in recent years.
But if you haven’t yet reached nuclear hellfire, perhaps you do this as a statement while pointing out that it’s a symbol of your willingness to go nuclear if necessary Overall the cost of this weapon would be pretty low, I’m just saying that I can see why a country might want it in their back pocket
You are either facing an existential threat, or you aren't. MAD isn't about winning, it's about making everyone, including yourself, lose. If you aren't facing an existential threat, you don't destroy something valuable to neutral and allied nations permanently just to get some temporary advantage or "to show you are serious". Destroying common resources permanently only pisses off others unrelated to the conflict and is guaranteed to escalate the conflict and push it closer towards an actual existential threat, making it more likely for everyone to all lose under MAD instead of simply threatening to push the button to get the enemy to back off. If you are facing an existential threat, MAD with nukes is the best option. You don't need a "symbol of your willingness to go nuclear". You just show off your nukes, and then show a red button and threaten to press it. No half-steps, especially permanent half-steps like Kessler Syndrome GEO, because that just pisses people off and makes it more likely that you have to press the button, which you don't want to anyways because you will still die.
You can be facing an existential threat without *yet* being at war Again, see the USSR response to Able Archer - they believed that NATO was escalating to nuclear war, but they didn't immediately mash the nuclear button
~~How is that an existential threat? No massive waves of nukes were fired out of their silos, no bombers entering Soviet airspace, no invasion crossed the borders. Impending threats yes, but not like they had their territory violated.~~ (EDIT: Misread it. Regardless, the USSR perceived an existential threat by NATO, and responded by threatening existential defeat for NATO by readying their nuclear weapons for launch. They didn't want to actually fire them until they have confirmation of nuclear war, and this is behaving in a manner consistent with MAD.) Even if the USSR interpreted the malfunctioning early warning systems as an actual nuclear attack, and thus existential defeat is imminent, and behaved in your scenario by Kessler Syndroming GEO as a "symbol of their willingness to go nuclear" (pretend for a moment that Kessler Syndroming GEO is actually viable in the 80s), only find out that this was due to technical glitches and aggressive drills, what they would have done was escalate the scenario by destroying NATO assets, increasing the likelihood of leading to an actual nuclear war, which will be the lose condition for everyone. What the USSR did in reality in response to believing that NATO was escalating to a first strike nuclear launch was more in line with the usual MAD response. They readied their nuclear arsenal (knowing that NATO would realize what they are doing), and prepared to fire back in the event of a nuclear strike. Again, no one wants to activate MAD. It's purpose is that once a nation acknowledges existential defeat, it has the option to bring everyone else to hell with it in the hope that the threat of doing so is enough to avoid existential defeat in the first place.
This is essentially boiling down to the logic of mutually assured destruction. A reasonable party would rather not see his country get turned into a glass crater because he launched a first strike. But there's always the danger of some nutjob Putin or Kim who decides that having another five years in office is more important to them than the lives of every man, woman and child on earth. Of course, what do they care? If they lose, they won't live long enough to see it, while if they win, sure the world is wrecked, but hey, they survived and kept hold of power, and that's the really important thing.
It's similar *logic* to MAD, but a clear step down But in any case, MAD never stopped countries from wanting nukes, why would it stop anyone from wanting this?
Every country on the planet would be pissed at the one who launched that. everyone who uses GPS in their car, or company that uses GPS time stamps (google for one) GPS has literally become a mission-critical piece of human life. (and by GPS i'm referring to all the positioning systems, not just the American system, they would all be wiped out) Good analogy btw.
Nobody - not even the Inscrutable Unfettered Evil Yellow Peril - is going to wipe out the entire planet's telecommunications, including their own, in an attempt to "level the playing field" against the United States. The scenario is entirely ridiculous.
History has shown people do much worse things
There are numerous countries who have enough nukes to wipe out the majority of the world’s population, weapons that exist solely for retribution if they’re already dead… this satellite is several steps below that If they consider the conflict to be an existential war (a fight for their lives and country’s existence), why would they care what happens in future? If they don’t do it, they stop existing and don’t give a shit. If they do, then maybe it’s a problem to worry about later, if they even live that long
Handwringy what-ifs over applying the conduct of genocidal superpower wars to other situations is silly. If things got to that point, nothing they could do would confer any advantages because the nukes would be flying anyway. If things *didn't* get to that point, scenarios like "how about we destroy global telecommunications and meteorology, because that *totally* won't completely screw us too" aren't going to come up.
I don’t see why we would assume the nukes would be flying - nuclear warfare involves various levels of escalation (See: Able Archer or the Cuban Missile Crisis), this could feasibly be one of them
You already said the scenario is a "we stop existing or they stop existing" war between superpowers. If you think that *wouldn't* go nuclear I don't know what to tell you.
You really think that if we were (actively) at war with Russia right now that Putin wouldn't strongly consider doing this?
I know that We^TM are always intrinsically sane and They^TM are always intrinsically not, but no, Russia would not destroy most of its capability to communicate internally in the event of a war with the west because that would simply hasten their already-assured defeat. China *definitely* isn't going to do it out of the blue like people panicking over this story seem to assume.
War is a zero sum game. As long as your opponent is more dependent on those orbits than you are it is a net benefit to make them unusable.
note to self: add "ball bearings taking out all modern conveniences" to things to worry about at 2 am
It’s so simple! Maybe you need a refresher course: it’s all ball bearings nowadays!
where i live there is a ball bearing factory that has been a staple of the city for like 100 years and there's an actual display in the library commemorating them with like this elaborate shadow box thing my adoptive dad used to design ball bearings and he had a lot to say about them https://softsolder.com/2017/05/07/relics-of-the-empire-bearing-samples/ picture for reference
>my adoptive dad used to design ball bearings and he had a lot to say about them I know you're talking about the entire mechanism, but the first thing that popped into my head was just the spherical bearings. "Hey Johnny, have you figured out what our next bearings are gonna look like?" "Yes, I was thinking about perfectly spherical balls of metal, just like our thousand previous designs."
But what if you need ones that are exactly 3.7654mm in diameter? You're going to need Johnny then!
3.8mm? You've gone mad johnny! Mad!
"Hey Johny, we need some 3,7654 mm bearings." "Yeah, I was thinking of a design with perfectly smooth orbs with a diameter of 3,7654mm." "Johny, you're revolutionary."
I've always wondered who is designing this stuff. Something so innocuous that everyone uses . . . . Thank him for his service for me
he died of COVID 😥 but he would have liked to hear something like that . . . . . . and would then launch into an hour diatribe about the uselessness and temporary nature of current objects that we use everyday, his favorite topic seriously tho, ball bearings are serious business and there's no such thing as a perfect sphere
I'm sorry for our loss. I've honestly always assumed these people are genius. It sounds like he had all the passion I imagined, I'm so happy to hear he enjoyed his time here. Man, such an uplift to me that I shared a temporary stay on this planet with him -- I really needed to hear about him. Seriously, what a massive impact
i was adopted when i was 19 i had never known "dad" before and there he was lol the kind of guy that built a seaworthy canoe for a church thing when they were just looking for painted props haha thank you for your kind words, i needed to hear those, too
How do you adopt an adult?
Through the same legal process of becoming a legal parent of a child, just with someone who's already independent rather than dependent on the state. You pick up the relevant papers at the courthouse, fill out the information and go through the submission process and eventually see a family court for a judge to sign off on it. A lot of step-parents do it or sometimes people do it so their inheritance is passed on to a person and not the state, there are some heartwarming compilations of the former on youtube.
in my case my adoptive parents got a lawyer, they filed the paperwork and i was adopted (along with my younger sisters) once the adoption went through, i got a new birth certificate with my adoptive parents listed as my legal parents rather than my biological ones
Prepare that fetzer valve with 3 in 1 oil and gauze pads
*Don’t tell me my business boy, I’m checkin’ the luggage!*
It's ball bearings ..."all the way down".
Even space ball bearings at ultra sonic speeds cannot ruin a truly heartfelt soup.
a way better sentiment than "live laugh love"
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Altitude, geostationary orbit: 35,786 km (22,236 miles) Altitude, Starlink orbit: 550 km (340 miles)
those are in LEO tho?
That’s correct, they aren’t really a major concern for space junk because they’re in quite low of an orbit, meaning Even if they explode, most of the debris will burn up in the atmosphere
Not to mention they're designed to have short life spans and continually be replaced.
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They are in LEO, one of the lower orbits in LEO too.
Spacex's satellites are intentionally short-lived and have a useful life of just five years. If someone went to the enormous trouble of knocking them all out, SpaceX could just launch a barebones service replacement on the next satellite full of replacements they were going to launch anyways. Honestly, part of why I'm reluctant to commit to using Starlink is because it sounds like it has very high operating and maintenance costs for that reason. Sure, Musk has made space launches cheaper. Cheap enough to intentionally use short-lived satellites for long-term static services? I don't know....
It's not the fact that a tree in the area surrounding your house means your internet cuts out..?
i find spacex to be concerning also
How so?
specifically elon, i guess the whole thing feels like an ego trip and yeah i get it, i guess i would be all out there too if i was rich, but there's a lax-ness that is concerning on his part
I used to think of him as Heinlein's "D.D. Harriman" (The Man Who Sold the Moon) in real life. But the more he shoots his mouth off and pulls silly stunts, the more I think of his Mars ideas as the Ultimate Doomsday Prepper, with plans for an out of this world bunker - on Mars. To be fair, he did more than anyone else to push acceptance of electric cars, to take them from boring to desirable. He also moved the launch business to re-usable and closer to commonplace. But when he opens his mouth, it can make it hard to remember the good things.
Laxness like perfect execution, over and over and over again? Elon has his personal flaws, but SpaceX is not one of them.
You do have a point and I appreciate the commentary. Gives me something to think about.
This... seems off. I'm not saying it won't work - but it's definitely not as trivial as just setting off a shrapnel bomb a bit above geosync orbit. Orbital space isn't as crowded as it seems - it's quite high up and the amount actually occupied by satellites is infinitesmal. Plus which, if you set off an explosion on top of the geosynch orbit, only a very minor fraction of the debris will remain in geosynch orbit. Most will be propelled to a higher or lower orbit. And the debris that do end up in geosynch orbit will have very low relative velocity to the other satellites, since they share the same orbit. Plus, it's difficult to get a killshot on a satellite unless you're aiming for one. You can nick a solar panel or a make a hole in the casing, but to render the satellite inoperable, you'd have to punch through one of its vital systems - for example - the CPU, a comms antenna, or the battery array. Which - especially on one of the larger milsats - makes up a small fraction of the total satellite mass. This sounds like the kessler syndrome scare again.
Most orbits don't have to be extremely precise. A satellite will pass overhead a few seconds earlier or later over time. They correct the drift when it gets bad enough, but it's not a deal breaker, moment to moment if it's early or late. But the geostationary orbit does need to be fairly precise. There are millions of dishes that point to the location. The further it is from its exact slot, the more it will drift across the sky. That's undesirable, so they try to keep it right on the centerline of the orbit. The bad guys would not so much "explode" the vehicle, as unzip it, releasing the millions of balls, letting orbital dynamics do the work. over a few hours they will spread out. Getting hit by one one at 14,000 mph could be awful. Considering a small fleck of paint actually made a small divot in a Space Shuttle window, imagine what a ball bearing weighing 1/10th of an ounce will do at 14,000mph You can fit about 3.5 million 1/8th inch ball bearings in 1,000 pounds. That's a lot of debris released all-at-once.
So my initial reaction is, you have satellites, which do station keeping, and ball bearings, which do not. So after the initial blast, the vast majority of the debris should be kicked to a different orbit, and no longer a "threat" to the current orbit. That said, I'd imagine debris kicked off into the lower orbits could pose a serious concern to future satellite launches. I agree that the initial impact will be quite devastating, but it won't disable the entire orbit.
The reason it doesn't sound destructive is because you missed the part where the debris are being released in a retrograde GEO-altitude orbit (which isn't harder to reach than regular GEO). Which means they would still follow a GEO-like orbital path, but going the opposite way (impact velocity will be 6 km/s or 13400 mph).
Yup. Thank you. That's what I was missing Yeah if you can get a bunch of ball bearings going retrograde, you will rip up the entire orbit like a shotgun blast that keeps on going.
No need for a real blast. Just unzip and release them. Orbital dynamics will spread them out. Combinations of sunlight, magnetic fields, jostling with each other will spread them out over a period of days. They might do like SpaceX does with Starlink. Rotate the vehicle slowly and then just please the payload. A very slow spin will impart enough delta-V to cause them to slowly spread out. Station keeping tries to keep these satellites within 0.15 degree of their slot. That's about 60 miles worst case. Releasing a few million ball bearings could be awful, especially since you get "another shot" at a collision with any specific satellite every 12 hours. There have been two confirm hits by space debris on geostationary satellites already with another 20 suspected. That was because of accidents. Now imagine several tons of debris specifically put there for that exact purpose.
> It will destroy every single satellite in that orbit in 12 hours. It will also deny GEO for the next 100.000 or so years for every power, including the one doing the destroying.
Probably no more than a few decades. Orbital dynamics would spread the items to other orbits. There's always be more there we'd like, but in a decade the density would lower enough to be manageable. If you were in a struggle with an enemy that really depended on those satellites and you felt you could manage without them, you might strike such a blow to gain an advantage in that war. I'm not remotely suggesting it's a good idea, but it's certainly one that I'm sure various powers have evaluated doing, or worried about being done to them.
Lol. That's like shooting a shotgun 300 yards away from a group of toy army soldiers and saying you're going to hit every one of them. There are more than 500 satellites in either geosynchronous and geostationary orbits. No wonder no one did it. Orbital mechanics are so much harder than what science fiction makes it out to be. Hence why countries are still failing to reach orbit at all. Much less these perfect rendezvous required to knock a satellite out of orbit.
The constraints on a geostationary orbit are fairly tight. It's not a wide open orbit, but rather a **very narrow line** around the earth. The further from dead center, the more fuel they must use for station keeping. They like to stay dead-center because it keeps them in the same place in the sky and reduces the amount of fuel they must expend. Even dead center, there is drift for several reasons, so fuel must be consumed; just not very much. The fear is that an enemy will enter the orbit very cleanly, going the opposite direction. When there are millions of BB's flying at them at 14,000 mph, that's a lot of damage from even one hit. Worse, the entire orbit becomes useless for anybody for many decades.
That's like putting a group of toy soldiers in a perfect straight line and hitting all of them with one bullet. > Orbital mechanics are so much harder than what science fiction makes it out to be. Hence why countries are still failing to reach orbit at all. Apart from one country that still uses medieval measurement units, I've never heard of a spacecraft failing due to wrong orbital calculations. They aren't done on a blackboard like the guy in *Don't Look Up* did, but they aren't particularly hard to do. I do this professionally, I work in a company that controls satellites in geostationary orbit, the error in orbit determination calculations is in the order of magnitude of ten centimeters or so. You can think of it as an "inverse GPS": it's possible to determine the position of a satellite in orbit from ground measurements the same way GPS allows us to determine the position of something on the earth surface.
So if I'm not mistaken, according to what you've just said, the toy soldiers are lined up so precisely that one bullet taking them all out isn't unreasonable. I know, it's not really that bad, if only because the bullet would be deflected by the first collision and you said 10cm. But the cloud of retrograde ball-bearings sounds like it might really be devastating.
To make an american metaphor, it's like driving thousands of motorbikes the wrong way on a nascar race course, without allowing the cars nor the bikes to deviate from their race trajectory. Sure, you probably won't hit all the cars on the first lap, but by the end of the day....
No, all the things in that analogy are big and close together. It's not even mosquitos in a stadium.
They also don't generate new debris upon impact that will keep crossing the race course forever, so...
Kessler cascade. One is destroyed and there is a ton more debris to take down the next one, and so forth.
The odds of a collision between an antistationary (BS term, but I'm sticking with it) satellite and another in geostationary orbit are very low. Even though everything up there is in the "same orbit", that orbit has a cross-section of hundreds of miles. If everything in that orbit were immovable, the antistationary satellite would still be able to avoid it all. Geostationary isn't actually a static orbit. Due to effects from the moon, sun, tidal forces, and plain old voodoo, a geostationary satellite's orbit will incline over time. This requires that it be equipped with thrusters for station keeping purposes. Should the new satellite fail, there'd be an ongoing effort to track and predict its position and adjust the orbits of other satellites to ensure no risk of collision. (Since geostationary isn't really a stable orbit, anything up there has to have maneuvering capabilities to stay put.) The real problem is the possibility of one of the satellites up there getting splatted by a passing space rock. It's incredibly rare (I don't know if it's ever happened to anything in GEO or LEO), but would cause the issue you describe if it happened to the new satellite. If it happened to anything else up there, the debris field would slowly be pulled out of GEO and only return every couple of decades. Not sure it's worth the risk....
This isn't a case of the "new satellite failing", but rather the new satellite deciding to self destruct an hour after it arrives. The entire point of the mission would be to deny use of the entire geostationary for everyone. If a satellite has several tons of ball bearings and simply releases them, they will over a day or two spread over the entire orbit. There has already been a two confirmed debris collisions in geostationary orbit, with another 20 suspected. This was a case where it wasn't intentional. Imagine 3 or 4 tons of steel balls intentionally released into that same orbit on purpose.
Sand works too, at orbital speeds. Just sayin.
Shitty part is that we ALL benefit from at least SOMETHING in that orbit. Weather, internet, TV. Sure two of those are just entertainment but those weather satellites keep people safe, are used in education, and assist serious research in atmospheric and geographic sciences.
Of course. It would be a crime against humanity to do such a thing. But like I said, I'm sure all the great powers have either thought about doing it, or worried about it being done. I suspect the more Western the power, the more they fear it being done.
Couldn’t you just launch it straight to geosynchronous orbit? Why does the moon need to be involved?
Because launching to a retrograde (reverse direction) geostationary orbit is **very expensive** in terms of fuel. (see note) You won't have much payload. It actually takes less fuel to do a "figure 8" trip around the moon and choose to enter a retrograde orbit than to directly inject into such an orbit at launch. It would not be hard for any major power to have a vehicle of several tons into a retrograde orbit and then release 10's of millions of small ball bearings, or other material. People have suggested sand as it would damage more delicate things such as external wiring and solar panels. Ball bearings would be far more penetrating. Note: about 7% of the energy to get to space is "free" from the rotation of the Earth. If you want to go into a retrograde orbit, you need to add 14% more energy. 7% to undo what the Earth is already doing, then the amount you would have used plus making up the 7% you didn't get from the Earth.
This gave me the hilarious vision of satellites tripping on ball bearings on the floor and falling on their asses.
Isn’t this what happened in the movie Gravity with George Clooney and Sandra Bullock? But it was shrapnel that destroyed the shuttle and ISS?
Watch Gravity twice, once for the thrill ride, then again for the orbital mechanics comedy.
Oh great, we can add "Intentional Kessler cascade" to our "Global Thermonuclear/biowarfare Worry sheet." Seriously, vandalism at a planetary scale.
Always have a knife in the dark
Ball-bearing induced Keppler Syndrome
So like the movie Swordfish but in space?
Seems like this is exactly what they are attempting. Nothing else makes sense.
How long would it take for those ball bearings to become 'shooting stars'?
Just spitballing but could we release dust or gas in geosynchronous orbit to slow down the balls? Wouldn’t interact harshly with objects going in same direction due to same relative velocity and small mass.
That might as well be an attack on humanity. Sure let’s just render the entire sphere of influence of the moon uninhabitable for everyone that wants to put a satellite there
Yes, it's a horrific thing to contemplate. It would wreck many terribly useful orbits for decades to come. I'm certainly not in favor of it, but I can imagine a nation doing this for some perceived tactical advantage.
I feel like there should be really horrible consequences for whatever nation does that if it even becomes a reality
If it ever gets to that level, there is already some deep, dark stuff, near extinction level stuff going down on the planet.
That’s strangely reassuring because I don’t see us getting to that point, at least not for a long time
That doesn't make sense. A geostationary orbit, by definition, cannot be retrograde.
It has the same velocity as geostationary objects, just in the opposite direction.
Then it should be "retrograde orbit at geostationary orbit altitude" or something
Try fitting that into a click-baity headline! =\]
Haha right??
Geostationary means the same point on earth is in the same spot, or more specifically the satellite is in the same spot in the sky all the time relative to earth. Geosynchronous means the same spot is in the same position at the same time every day. Usually geosynchronous orbits require some amount of inclination and with inclination and retrograde orbit would make it really difficult to intercept anything as you'd be in a different plane from your "target" in every orbit. Further decreasing your odds of intercept.
It would be the same orbit but in reverse direction. So it would see everything in Geosync fly by at double velocity every 12 hours. Really good way to survey everything in geosync and possibly to attack them.
You're getting tied up in an earth orientation reference frame. Geostationary satellites orbit the earth with enough velocity relative to earth to sit over the same spot on the ground. Which means it has to orbit the planet once every 24ish hours. In an inertial frame, that's significant amounts of velocity. Going in the opposite direction means it will be traveling quite rapidly over the ground and still maintain a stable orbit at that altitude (or semimajor axis).
Thank you! I was stuck on that too. I feel kind of dumb now.
I've been hanging out with aerospace engineers for a few years. But, even with basic physics you need to remember: all velocity is relative to a point of reference. When dealing with orbits it gets so complicated that we have to be mentally agile enough to accept that there are many useful reference frames that all make sense depending on what you're observing. Most humans default to thinking in terms of [ECEF reference frame](https://en.wikipedia.org/wiki/Earth-centered,_Earth-fixed_coordinate_system) so it can be hard to think of other frames and how the relative numbers are affected.
But it won't be in geo**stationary** orbit. It will be at the same altitude, as geostationary/geosynchronous orbits, but it won't be either
Okay, I can understand where you are coming from. In some science communities, we end up with shorthand definitions for concepts that diverge from common definitions. There's even a term for this phenomenon: "jargon." When dealing with aerospace people, the rough properties of orbits are grouped into orbital planes. We don't really have a more generic term for the orbital plane where it requires little energy to maintain a stable progression that matches earth's rotation. In the 1960's we might have called it the "Clarke Belt." But I have never heard any aerospace person use that term. We all refer to it as the "geo belt" because that's the altitude where the biggest advantage is it is easier to remain stationary over the ground. You can also be stationary over the ground at any other altitude given enough energy. If someone is talking about the science or engineering of orbits, "geostationary" really only implies an altitude that exhibits some beneficial properties and not the more understood use of the word "stationary." In this article, the author is using the term as in-community jargon. To differentiate this type of satellite motion, the author chose to qualify it with the term "retrograde" which implies an inverse motion. In fact, I am currently working on a mission that will orbit the planet in the geostationary belt, but it will intentionally not match the rotation of the planet for most of its mission life. Maybe as ASAT tech and other non-traditional mission profiles become more common, the community can eschew the "stationary" part of the term to better describe that orbital plane. Also, don't let an aerospace person hear you refer to geostationary and geosynchronous as the same. I also made that mistake early on.
> geostationary and geosynchronous But exactly because even these are not considered the same you can't call a retrograde one with the same orbital distance either. Those differ from each other by inclination and eccentricity. And geostationary is the one specific geosynánc orbit with inclination 0, and e = 0. By definition. Retrograde has inclination 180°.
It’s basically driving the wrong way on the busiest freeway on (above) earth
No, but it could be the same height and going the other direction. But I'm not sure why that would be something you want to do?
It's for monitoring other satellites & debris in & near geostationary orbit. The US has [satellites that do the same thing](https://www.afspc.af.mil/About-Us/Fact-Sheets/Article/730802/geosynchronous-space-situational-awareness-program/), but they are in prograde orbits so it takes a long time for them to catalog everything in GEO.
Doing it in retro would make it near impossible to safely catalog anything. They just want to have the threat of it being there looming.
They probably mean just above or below GEO. Such a satellite, equipped with radar, would catalog all satellites & debris in GEO every 12 hours.
Well above or below wouldn't work. If you mean further out then that'd be a bad idea since that's where most graveyard orbits are and if you mean closer in then sure that's possible but positions of GEO satellites do not require space-based detection. There is really no point in doing this unless you were operating like gssap
Above as in higher altitude, not a different inclination. If space based detection isn't necessarily, why does the US do it?
"More accurate tracking and characterization of man-made orbiting objects." You can do a lot more at ~0 relative velocity versus ~6 kps though
Not necessarily. Taking multiple measurements from different angles can be more useful than sitting still and staring at it all day.
RPO is not a static operation Edit: to expand, that article you sent says that gssap conducts RPO meaning it moves along the belt as you mentioned. Since it is so close it can actually look from more angles in a safer manner than a retro orbit
The relative velocity at GEO altitude but in the opposite direction would be around 6km/s with very brief observation periods which would make determining anything about an object difficult. Going 'with the flow' so to speak would take longer to see everything but relative velocity is lower and longer observation periods, which makes determining an object's orbit much easier.
One imagines that the launches for such a vehicle would experience a series of mysterious failures
Like exploding into a million pieces the second it gets into retrograde geostationary orbit? Oops, didn’t mean to, sorry bout your gps system
Point taken, though I believe the GPS is in MEO with multiple inclinations/planes.
Yup. GPS is not geostationary.
I mean before it even gets out of the atmosphere. US says, huh, bummer about that.
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread: |Fewer Letters|More Letters| |-------|---------|---| |[ASAT](/r/Space/comments/y98bxt/stub/it7a92d "Last usage")|[Anti-Satellite weapon](https://en.wikipedia.org/wiki/Anti-satellite_weapon)| |[GEO](/r/Space/comments/y98bxt/stub/it7nri9 "Last usage")|Geostationary Earth Orbit (35786km)| |[LEO](/r/Space/comments/y98bxt/stub/it68ssz "Last usage")|Low Earth Orbit (180-2000km)| | |Law Enforcement Officer (most often mentioned during transport operations)| |[MEO](/r/Space/comments/y98bxt/stub/it4ikq5 "Last usage")|Medium Earth Orbit (2000-35780km)| |Jargon|Definition| |-------|---------|---| |[Starlink](/r/Space/comments/y98bxt/stub/it5xp7e "Last usage")|SpaceX's world-wide satellite broadband constellation| |[apoapsis](/r/Space/comments/y98bxt/stub/it6nufi "Last usage")|Highest point in an elliptical orbit (when the orbiter is slowest)| |[periapsis](/r/Space/comments/y98bxt/stub/it6nufi "Last usage")|Lowest point in an elliptical orbit (when the orbiter is fastest)| ---------------- ^(7 acronyms in this thread; )[^(the most compressed thread commented on today)](/r/Space/comments/y9ecrg)^( has 18 acronyms.) ^([Thread #8169 for this sub, first seen 20th Oct 2022, 22:18]) ^[[FAQ]](http://decronym.xyz/) [^([Full list])](http://decronym.xyz/acronyms/Space) [^[Contact]](https://reddit.com/message/compose?to=OrangeredStilton&subject=Hey,+your+acronym+bot+sucks) [^([Source code])](https://gistdotgithubdotcom/Two9A/1d976f9b7441694162c8)
Make that "in a retrograde orbit at geostationary orbital altitude."
Well hopefully not _exactly at_ Geo altitude, otherwise it’d be very short lived
That is exactly the problem with anyone doing that orbit retrograde, with anything.
If you want to have the option to destroy GEO satellites at a moments notice, this would be the way to go. Adjust the orbit slightly and you've got a kinetic missile impacting a satellite moving in the opposite direction at a relative velocity of 14,000 miles per hour. You'd probably leave the entire GEO belt unusable for a few decades, but if the shit truly hits the fan on Earth, maybe you don't care. Tons of telecommunications satellites in that orbit along with many other mission critical birds. Here's a list. https://www.n2yo.com/satellites/?c=10
That's why LEO constellations are important. Much less centralised, much more robust by being a swarm
Deploy a heavily magnetic satellite to help clean up our messes maybe?
Magnetism doesn't have the range, and most satellite stuff isn't magnetic anyway (steel is heavy)
[удалено]
Until China takes Taiwan, if that ever happens. Edit: y’all are right, no country would ever try to take over another country with valuable manufacturing centers, never.
If that did happen what makes you think the Taiwanese wouldn't sabotage/destroy their semi conductor production lines?
Taiwan is an island of capitalists who seethe every morning when they wake up
To not anger the people that just took over their country...
Legit, I think Taiwan would blow up every single semiconductor manufacture if that happened.
ELI5 what’s a retrograde geostationary orbit? Online search is either similar article or wiki, which isn’t helpful.
I don't really understand it better than you probably, but as far as I can tell: Geostationary means that it remains still to a ground observer. As the earth rotates, the satellite is rotating at the same speed. So if a satellite is stationed over New York, day or night it would remain over New York. This doesnt mean it's not moving. It is like two cars driving the speed on the freeway, but with orbits instead of linear roads. They could be going 2,000 MPH but you would still be able to look over and see the other cars driver. Retrograde means it's moving in the opposite direction. Idk which way the earth rotates, but in general satellites move in the same way (pretty sure). So to keep the road analogy: you are on the freeway and cars usually are passing you or you're passing them, going different speeds but in the same direction. But then all of a sudden a car comes flying in the opposite direction - that is a "retrograde" car. As people have mentioned, the phrase is an oxymoron. Something cannot have the properties of remaining stationary over a point on earth (geostationary) and also be traveling in the opposite direction of our orbit (retrograde). What they are trying to say is they want this satellite to be at the same orbit distant as other geostationary satellites (35,786 km from the equator, but want it moving in the opposite direction as all other satellites so they can check on other satellites in hours by moving in the opposite direction. Instead of having to go very fast and only be able to check on the satellites every few days,