This is an interesting topic and one that isn't confined to just LEO. GEO is another busy area that has this issue... there seems to be something already in place because there is talk of who has what "slot".Ideally this will be worked out by the first few parties setting up a coordination board or something similar. I can think of a number of schemes to decide "who should move"... it may be that unique science satellites get precedence. It may be that the satellite with less fuel remaining gets precedence... who knows. (Could the Space Data Association evolve into such a coordination facility? http://www.space-data.org/sda/ Will it fall to CSpOC to do this? Note: the "executive members" are some old line satellite companies, and SpaceX doesn't seem to be listed as a member at all...http://www.space-data.org/sda/participants/ If that's not just an omission it's quite surprising)
Fwiw the situation is symmetrical. Don't demand that the other guy move - move your own damn bird.If you can't (say low on fuel) ask nicely and hope.Also, an oz of early maneuver is worth a pound of late maneuver.
Quote from: meekGee on 09/03/2019 10:51 amFwiw the situation is symmetrical. Don't demand that the other guy move - move your own damn bird.If you can't (say low on fuel) ask nicely and hope.Also, an oz of early maneuver is worth a pound of late maneuver.That represent a big problem too...is you bird cost 1000 millions $, and the cost of move in propellant is a lot more expensive that a simple small sat, you expect that the cheaper and smaller bird, move first...The real questions, is all this will need regulations, and somebody for do this job internationally...If tomorrow, X company, or a country not very friendly... put a femto satellite, in the orbit of one of the starlink satellite, and refuse to move, they don't will be happy either...
If tomorrow, X company, or a country not very friendly... put a femto satellite, in the orbit of one of the starlink satellite, and refuse to move, they don't will be happy either...
For sure, just like in the water - motor yields to sail, right? So chem prop yields to electric
For sure, just like in the water - motor yields to sail, right? So chem prop yields to electric.Also, by sheer necessity, expensive birds yield since that's what's going to happen anyway since the cheap bird is willing to take more risk, that's just a fact even if it's unfair.
As we talk about outer space...we need an international organism for control this...What about Unoosa for this job?http://www.unoosa.org/
Quote from: meekGee on 09/03/2019 03:08 pmFor sure, just like in the water - motor yields to sail, right? So chem prop yields to electricElectric propulsion should be fine for avoiding these situations. I think having deorbiting sats that are still under control steer around active and stable operational sats would be more fair.
Quote from: gongora on 09/03/2019 04:14 pmQuote from: meekGee on 09/03/2019 03:08 pmFor sure, just like in the water - motor yields to sail, right? So chem prop yields to electricElectric propulsion should be fine for avoiding these situations. I think having deorbiting sats that are still under control steer around active and stable operational sats would be more fair.That right there is the one no-brainer rule. If you're at end-of-life, might as well off yourself. Works for ppl too As for electric propulsion in general, not sure what the thrust is. If they want to scootch a few km over a period of hours, that's not trivial. Over days, probably more feasible.Not sure if it was even an option here, but the most important thing is - there is no agreed upon obligation, and ESA can't (or rather shouldn't) run around insinuating SpaceX broke some rule or understanding.
Quote from: gongora on 09/03/2019 04:14 pmQuote from: meekGee on 09/03/2019 03:08 pmFor sure, just like in the water - motor yields to sail, right? So chem prop yields to electricElectric propulsion should be fine for avoiding these situations. I think having deorbiting sats that are still under control steer around active and stable operational sats would be more fair.I agree. I think you could build up a whole set of precedence rules and weights- who can do it more easily should do it - who is closer to end of life should do it- who has better margins remaining should do it- science trumps commercial- first in orbit has right of way- When moving, ascending node moves out, descending node moves inalong with some rules about which rules take precedence over which other ones(those are just ideas for possible rules, not my actual feelings)
Quote from: Tywin on 09/03/2019 04:09 pmAs we talk about outer space...we need an international organism for control this...What about Unoosa for this job?http://www.unoosa.org/It is not at all clear that a regulatory body is needed, or feasible... What is needed is a coordination body. The SDA might be ideal for that. (regulation is not the only way to solve disputes, voluntary cooperation is often more efficient, and for regulation to work at all, the regulatory authority needs to have enforcement authority. What enforcement authority would any UN body have?)
Also, Alastor makes a great point. Actually calculating cost and paying back and forth can really sharpen thinking. Economic incentives work.
Quote from: Lar on 09/03/2019 05:33 pmAlso, Alastor makes a great point. Actually calculating cost and paying back and forth can really sharpen thinking. Economic incentives work.Economic incentives work a lot of the time. In some cases, though, they lead to unintended consequences, so they have to be very carefully set up.Who decides the costs for each organization? It seems like this system would heavily incentivize each organization controlling a satellite to give the highest possible cost estimate for its avoidance, and that can lead to intentional or unintentional distortion and sub-optimal behavior.
Economic incentives work a lot of the time. In some cases, though, they lead to unintended consequences, so they have to be very carefully set up.Who decides the costs for each organization? It seems like this system would heavily incentivize each organization controlling a satellite to give the highest possible cost estimate for its avoidance, and that can lead to intentional or unintentional distortion and sub-optimal behavior.
Quote from: ChrisWilson68 on 09/03/2019 05:47 pmEconomic incentives work a lot of the time. In some cases, though, they lead to unintended consequences, so they have to be very carefully set up.Who decides the costs for each organization? It seems like this system would heavily incentivize each organization controlling a satellite to give the highest possible cost estimate for its avoidance, and that can lead to intentional or unintentional distortion and sub-optimal behavior.Good point. We could imagine that launch contracts and satellite procurement contract all have to be disclosed to a single third party (of course with the right confidentiality requirements) that would be tasked with calculating collision avoidance fees, but there are cases where this wouldn't even be feasible. Starlink is a great example of that. Since everything is done in an integrated way, there is no launch contract or satellite building contract and this would at best be declarative. Military or intelligence satellites would be another corner case (but they are a corner case for satellite avoidance anyway. With these you just have to assume that they will perform all necessary maneuvers themselves and not tell nor charge anyone since they don't want details about what they are doing to be disclosed). You could also just say that you have to declare to a third party what you will charge per maneuver per kg of fuel at launch and have that be public data and that's it. Then if you don't want to maneuver or if you want to play a game of charging all the maneuver cost to other parties, you'll declare a high price and probably end up being the one that pays most of the time. The downside is that small satellites that have very low maneuvering costs may try to make a benefit of this because they are so much bellow bigger ones. In the end, I think most of the cases are handled by the rule I added in my edit : If you are intentionally putting yourselves on a collision course with the intent of "collision trolling" other parties (this is why this second rule is essential), you'll end up supporting all the costs of subsequent maneuvers. So in most of the cases, either it's an accidental conjunction and it's very rare, so someone charging a bit more than they should isn't really a concern or if there is an orbit that ends up being shared, there will be an agreement before anything happens that would cover who pays what and who does what. Another point in favour of a system that makes people share the costs comes from something ESA mentioned, which is that most avoidance maneuvers involve dead satellites. Which means that would put an economic incentive on deorbiting or avoid populated areas to park dying satellites. It might help reducing LEO clutter if done properly. P.S. : I also like the "pay me what you'd charge" idea. Although again, you have to be careful with the risk of a small provider "collision trolling" big sats.
In that case I see two thing that should be add...Insurance policy (who pay and how many pay for maneuvering)...and mutual fund for any case of collision somebody pay anyway to the company that was a victim of this collision...Because if a small company do wrong stuff in the space, and for any reason cause a collision, and the cost that will need to pay is a lot more that the asset that have that company... still somebody have to pay to the victim company, and somebody should be pay for clean that orbit of debris...
Well at least in the sea I think so is the contrary...if you are in the ocean with you yatch and you are in a collision course with a Oil tanker ship...you are the ship that have to move...becuase the bigger ship have priority...
And to bring it back on topic, you can be sure that a formal International Regulations for Preventing Collisions in Earth Orbit / Outer Space (how wide do we want the scope to be?) would be even more voluminous once all the edge cases are incorporated.
That right there is the one no-brainer rule. If you're at end-of-life, might as well off yourself.As for electric propulsion in general, not sure what the thrust is. If they want to scootch a few km over a period of hours, that's not trivial. Over days, probably more feasible.Not sure if it was even an option here, but the most important thing is - there is no agreed upon obligation, and ESA can't (or rather shouldn't) run around insinuating SpaceX broke some rule or understanding.
I've been harping on the need for the equivalent of a Coast Guard for space for a long time, especially since it will suffer from the tragedy of commons quickly, and risking kessler syndrome. In the context of extracting money from the parties involved to operate said organization's operations, which could include things debris removal (subcontracted out to providers), rescue and safety (subcontracting out tug/OTV services?), and in this thread's context traffic control, fee structures that force the one being most inconvenienced (due to expenditure of propellant or disruption in service) to be paid by the intruder seem more equitable. We have ICAO for airplanes roughly, IMO for ships, and ITU covers space telecomms roughly (which the majority of commercial sat operators would have to interact with now).Shifting some COLREG's stuff like EPIRB detection network responsibilities to a Space Guard could be a foundational start as well.In the past, there were discussions about a launch tax/debris deposit to go into an escrow fund to cover problems. Though this has a lot of connections to space insurance itself, as an interconnected industry. Is there a space insurance trade group that could better get a handle on the whole perspective? Insurance has to regularly deal with freeriders and actual risk assessments, as well as the actuarial tables on the probabilities of things happening.That, and pecking orders is non trivial for avoidance. Such asmannednational scientific/public service (weather observation, GNSS)commercialamateurnational militarywhile greatly simplified, misses a lot of subtlety.This also puts unequal pressures on sats without propulsion (by design or by accident), and owners of larger debris/spent stages, if we assume the non-maneuvering has to pay the cost of the avoidance, as cubesat operators are generally poorly funded to begin with, so self-removal or paying for third party removal/tow is a troublesome aspect representing a potential barrier to entry. Though one might argue that is actually good as it encourages an OTV/garbage scow debris removal industry.
If all the mega-constellations launched, Peterson found that current tracking technologies would generate over 67,000 “collision alerts” annually. Operators would then have to choose whether to make hundreds of precautionary satellite maneuvers a day, or risk the small chance of a collision.
Quote from: meekGee on 09/03/2019 10:51 amFwiw the situation is symmetrical. Don't demand that the other guy move - move your own damn bird.If you can't (say low on fuel) ask nicely and hope.Also, an oz of early maneuver is worth a pound of late maneuver.The point the ESA was trying to make was not so much the need to hash out who moves their spacecraft (and just as importantly, who doesn't move), but that there needs to be a formal framework by which these communications occur rather than through ad-hoc emails and phone calls between operators. There is no current analogue to ADS-B.
by Wednesday 28 August the team decided to reach out to Starlink to discuss their options. Within a day, the Starlink team informed ESA that they had no plan to take action at this point.[...]Contact with Starlink early in the process allowed ESA to take conflict-free action later, knowing the second spacecraft would remain where models expected it to be.
It was just a PR hit, bad for everyone. The way Wyler and Forbes jumped in was highly indicative
Quote from: meekGee on 09/04/2019 02:11 pmIt was just a PR hit, bad for everyone. The way Wyler and Forbes jumped in was highly indicativeWyler appears to be in the process of getting his head handed to him for that... PR stunts often backfire.
Quote from: Lar on 09/04/2019 03:12 pmQuote from: meekGee on 09/04/2019 02:11 pmIt was just a PR hit, bad for everyone. The way Wyler and Forbes jumped in was highly indicativeWyler appears to be in the process of getting his head handed to him for that... PR stunts often backfire.Well looks like he don't give up...https://twitter.com/greg_wyler/status/1168988584818425857
Quote from: Tywin on 09/04/2019 05:03 pmQuote from: Lar on 09/04/2019 03:12 pmQuote from: meekGee on 09/04/2019 02:11 pmIt was just a PR hit, bad for everyone. The way Wyler and Forbes jumped in was highly indicativeWyler appears to be in the process of getting his head handed to him for that... PR stunts often backfire.Well looks like he don't give up...https://twitter.com/greg_wyler/status/1168988584818425857Jesus can you imagine being in business with him? Sleazeball.
It's not a big deal. Only typically need to move a satellite a few meters a day in advance of conjunction. Doesn't shorten life appreciably of satellite. We've been at it since 2009 when good catalog data was made public (thanks, unfortunately to our SV33 collision from no data).
Quote from: Lar on 09/04/2019 03:12 pmQuote from: meekGee on 09/04/2019 02:11 pmIt was just a PR hit, bad for everyone. The way Wyler and Forbes jumped in was highly indicativeWyler appears to be in the process of getting his head handed to him for that... PR stunts often backfire.Well looks like he don't give up...(tweet deleted)
There is no current analogue to ADS-B.
The cost to maneuver in LEO, particularly low LEO, is basically irrelevant. In the case of Aeolus, it uses twice as much propellant every day to make up for atmospheric drag as it did to avoid the Starlink. The orbital changes we are talking about here are extremely tiny. Aeolus only used 0.1 m/s of delta-v to effect a 350 m change in height on the other side of the orbit.
Quote from: envy887 on 09/04/2019 06:38 pmThe cost to maneuver in LEO, particularly low LEO, is basically irrelevant. In the case of Aeolus, it uses twice as much propellant every day to make up for atmospheric drag as it did to avoid the Starlink. The orbital changes we are talking about here are extremely tiny. Aeolus only used 0.1 m/s of delta-v to effect a 350 m change in height on the other side of the orbit.The cost of maneuvers may be irrelevant now, but we also have to consider also the future. One thing is for sure, which is that the number of objects in space is about to raise quite sharply with both the development of the small sats market and the launch of several mega constellations. Not only this, a lot of actors are entering the market. With few actors, it's not very hard to make sure that all actors will act properly and with a relatively low number of sats, the number of encounters is relatively low, so it's not that relevent. as you point out, especially compared to drag in very low orbits. However, once you multiply the sats in orbit by a number of 10 or so, and you add many actors, you significantly increase the risk of having to maneuver very often if you are not careful, disrupting service and having these insignificant costs add up to something that suddenly becomes significant. Especially if some of these new actors are not as carefull as they should about other actors, which you could easily see happening with some actors having to take care of several thousands of sats, where others have a few to a few dozen satellites. If you push this even further, you could imagine someone trying to mess with their competitors by intentionally putting some sats in a disrupting orbit. I think the worry expressed in the past few days comes from people looking at the curves of the number ofobjects in space and saying "yeah, if we multiply the number of daily encounters by the increase in sats we can expect, that would definitely become a problem". And I'd consider this worry to be justified. A regulation could be overkill, but also can be expected to prevent big problems for some users of space, so it's probably worth it.
Is it reasonable for sats to be able to detect the beacon of another and maneuver enough to not hit, assuming we really minimize their keep-out spheres?
“Space traffic management” is the cyber security of the space world. It is a hugely important public policy issue that underpins the successful future expansion of space activities, yet there is no agreement on its definition.
First, there needs to be a decision on whether the U.S. military will continue to provide all of the space situational awareness (SSA) data and services for the world, a task they took on after the 2009 collision between the Iridium 33 and Cosmos 2251 satellites. But the growing demands and complexity of the safety of spaceflight mission are increasingly competing for resources with the national security mission of the U.S. military, as multiple senior leaders have pointed out. Instead, it’s time to separate the civil SSA functions for safety of spaceflight from the core national security SSA functions, and assign the former to a civil federal agency.
However, the reality is that ICAO was created to resolve differences between national regulatory frameworks and relies on national administrations to implement and enforce its standards. Thus, it is extremely unlikely an “ICAO for space” would be successful before the existence of any national regulatory frameworks for space traffic management.
Commerce requested $10 million for the Office of Space Commerce to create a new organization for space traffic management starting in fiscal year 2020. The government is currently operating with temporary stopgap funding and it’s not clear when Congress will pass appropriations bills for federal agencies.
Constellations, though, may not be the biggest threat in LEO. Darren McKnight of Centauri said the bigger threat comes from hundreds of upper stages, primarily Russian, left in three “clusters” in low Earth orbit at altitudes between 775 and 975 kilometers. The stages are large, with masses of up to 8,000 kilograms, and can’t maneuver.The threat is not theoretical. McKnight said that, in May, two of those stages passed within 87 meters of each other at a relative velocity of 14 kilometers a second, missing a collision by just seconds. Had they collided, he said, “it would have doubled the catalog population in one event.”
Interesting news about this future problem...https://www.esa.int/Safety_Security/Space_Debris/Automating_collision_avoidancehttps://spacenews.com/u-s-space-command-eager-to-hand-over-space-traffic-duties-to-commerce-department/QuoteCommerce requested $10 million for the Office of Space Commerce to create a new organization for space traffic management starting in fiscal year 2020. The government is currently operating with temporary stopgap funding and it’s not clear when Congress will pass appropriations bills for federal agencies.https://www.technologyreview.com/s/614693/how-the-worlds-biggest-gun-helped-solve-a-long-standing-space-mystery/
