FCC Approves 5 Year Satellite Deorbiting Rule
payloadspace.com
payloadspace.com
For most satellites below ~450km, this is really a non-issue. Atmospheric drag will generally be sufficient to deorbit the satellite in a few years. For big Earth-observing constellations, Starlink and friends, and many small missions, this doesn't change anything. Debris don't really accumulate dangerously in this zone and collision avoidance is a well-studied problem with a lot of people doing great work. The 18th SDS with the US Space Force, LeoLabs, Starlink/SpaceX, and a lot of other constellation operators take this very seriously and do a good job.
For satellites in the 800km+ range, this is also not a meaningful change. The 25-year rule meant that these satellites needed a deorbit plan anyway. 800km is a rough estimate, in real life it depends on the satellite mass + geometry and the solar cycle.
For satellites in the 450-800km range (again - hand waving here) this is actually a big deal. Satellites that would decay naturally between 5 and 25 years now need an active deorbit plan or need to launch lower and keep themselves up with propellant. Small satellite propulsion is becoming cheaper and more available, so this isn't that onerous for commercial operators. But I do worry a little about educational and non-profit launchers of satellites. They'd be excluded from using launches to this orbital range unless the FCC allows waivers (which I'm hopeful they will).
Overall I don't think this has a particularly big impact. It's a sensible revision of an old rule that was a little too lax. But there aren't that many satellites launching at the high end of the 450-800km range without propulsion. The 1000km-2000km area is a more important area for debris mitigation and that was really already covered.
As for the FCC having this jurisdiction vs. the FAA or the USSF, as Spock would say - "it is not logical, but it is true."
I think this line of thinking is dangerously incorrect. Sure it’s not a problem right now but we’re poised to have a lot more stuff in orbit than we’ve ever had before. Plastic waste didn’t initially “accumulate dangerously” either but once it became more widely used (and did accumulate dangerously) it was much more difficult to try to reign it back.
Actually less than that, as orbits with more decay time have more vertical space.
This is most obvious with geostationary orbit. Over a single year you could have say 10,000 satellites in geostationary orbit with essentially zero risk of collision, but without station keeping risk continues to grow every year those 10,000 satellites drift around.
It looks like inactive geostationary satellites will drift to the same longitudes, and tilt their axis away from the pole. If you have a set of geostationary satellites in that situation, the risk of collision is still quadratic in growth.
The risk is the sum of the pairwise probabilities of collision. So the only way you get super quadratic is if incrementally added satellites have increased pairwise risk with other satellites. It is possible that could be the case, because if you have to pack satellites more tightly, then maybe each satellite has higher pairwise risk with its direct neighbors.
That would still be sub-exponential, unless the collision risk between two satellites got exponentially higher as they get more closely packed. For example, suppose you have a ring of satellites, and you double the number. Then immediately neighboring satellites are twice as close. By basic inequalities you can show that considering the non-neighbor pairs of satellites, they have less than quadrupled the total risk of a collision. So by the master theorem we know the risk of collision would only grow exponentially if there were an exponentially higher risk of collision between two neighboring satellites in terms of the reciprocal of their distance. But that is not the case, is it? You’d expect it to be polynomial. Fewer orbits before the satellite drifts past its neighbor, a smaller expected distance to the neighbor as it drifts past… as with most physics problems these are linear components, multiplied together.
15k satellites per year with a 5 year lifespan and a 1-year decay means you'll be stable at 75k satellites. 5 year lifespan with a 3-year decay means you'll eventually be stable at over 100k satellites in orbit with 30,000 of them 'dead' and decaying. That's a massive difference in collision risk.
Is it? It's a big difference in absolute numbers but that doesn't mean it's a meaningful difference in Risk.
If both numbers are quite small relative to the level of concern, the difference can still be irrelevant.
My point is that it takes more than just looking at the number of satilites to understand risk. You need to do the work to show how the collision chance compares to what an acceptable limit might be. Both cases could be very acceptable (or both cases could be unacceptable).
If something was going to deorbit within 1 minute, or was going to deorbit within 4 years, 6 months... It doesn't matter to the creator, because they don't have to change their design at all to meet the rules.
If something was going to deorbit within 8 years (because they previously had a 25 year allowed limit), they now have to rework the design.
There's plenty of room for debate about if 5 years is adequate, but as it stands, _most_ things (under 500km) will naturally deorbit within the legal time frame anyway even without special consideration.
If deorbiting in years is sufficient, the difference in 1 minute vs 4 years is NOT relevant -> to a satellite builder worried about the law.
If everything deorbits within 5 years, the only way for more things to accumulate is to launch things faster. But that's a separate discussion. If everything launched today is deorbited within 5 years, then in 5 years, all satellites will be new satellites launched after today. If everything launched today is deorbited within 5 months, then in 5 years, all satellites will be new satellites launched after today. Deorbit speed under a threshold has no bearing on accumulation beyond that threshold.
If SpaceX launches a trillion Starlink satellites, and they all deorbit within a year, then yes. it's going to be a very crowded year, and we'll have to drastically rethink how much stuff we have in LEO, but at the same time SpaceX would not be in violation of the 5 year deorbit window, so the issue is about how much stuff we're sending up, and not how fast it de-orbits.
"Amount of junk below 450km, total" and "Amount of junk below 450km, that hasn't deorbited after 5 years" are very different things. You're making points about total, while the original point was about deorbit speed.
One time is 10^12 times longer, but the difference does not matter to me. My emails are still sent and received faster than I can possibly perceived.
population = arrival rate X duration of visit
I am worried though, do we really build satellites that are expected to only work for 5 years? Are we disincentivizing people from building 20 year satellites this way?
"Gabbard Diagram for Low Earth Orbit 1959-2021"
See how the stuff in the lower left corner speeds up towards the lower left corner? That's low flying debris falling out of space.
- Most debris deorbits naturally in a few years. Any debris causing events or accumulation naturally clears out in a reasonable time frame. It's not like debris at 800-2000km which is the real "Kessler Syndrome" concern where it takes decades or centuries.
- Debris mitigation efforts that are already in place are effective. Limiting debris release during launch and deployments has had a huge positive impact over the last few decades.
- "Traffic control" is a lot easier at these altitudes and debris in this range is well tracked. Obviously this doesn't extend to small stuff (<5cm), but due to active mitigation and natural decay this is less of an issue. Also ground radars are getting better and can actually see a lot of these objects now.
https://www.nasa.gov/smallsat-institute/sst-soa/deorbit-syst...
Two satellites hitting at an acute angle should produce a cone of debris in front of them, of which about a third deorbits and a third goes up into a higher orbit that's an average of the two.
Two satellites that hit at an obtuse angle, well, they pancake and produce a donut of debris. The stuff headed straight up is on a parabolic orbit that will hit the atmosphere on the way back down, but in the meantime any other satellite that crosses paths with it is effectively hitting a wall of stationary debris, creating a new cone that ladders up higher. Is there enough space that the ladder stops, or does it just keep building?
One of the quirks of debris deorbiting is that drag is exponentially higher the lower you are in orbit, and any drag that the debris experiences at any point along its orbit will manifest in a reduction of altitude 180 degrees along is orbit on the other side. So if you have a piece of debris with an eccentric orbit, let's say 300km at periapsis and 1,000km at apoapsis, after a fairly brief amount of time you'd expect the debris to have a periapsis of 299.9km and an apoapsis of 500km. Then perhaps 299km periapsis and a 350km apoapsis. etc. I'm making these numbers up but you get the idea: the high point in an orbit is the part that drops the quickest.
Even if you were to launch 100,000,000 full sized satellites into orbit at 400km altitude and deliberately orchestrated Kessler syndrome, space would be unusable for a few years, but would be 100% back to normal after 5 years.
The dangerous orbits are those in the 500-2,000km range. Satellites whose orbits never bring them low enough to experience significant atmospheric drag. Those are the satellites this new rule is targeting.
On the second point about parabolic orbits I also find that probably relatively low risk because we are only talking about a fraction of an orbit for a collision to occur so unless the debris field was massive the chance of another collision is probably still low. Remember when we are modelling orbit collisions normally we are often talking over 25+ years - 100,000 + orbits.
I think the main problem is busy orbits (e.g. sun-synchronous polar orbits at popular altitudes) where most of the debris remains roughly in the same orbit following an acute collision but has a lot of other potential collision targets. Also as satellites are disabled by a collision they lose the ability to avoid other objects already in the same crowded orbit - i.e. the fraction of objects able to take avoidance decreases increasing the chance that future collisions are from 2 incapacitated satellites, removing the possibility of avoidance.
> The Report and Order adopted today requires satellites ending their mission in or passing through the low-Earth orbit region (below 2,000 kilometers altitude) to deorbit as soon as practicable but no later than five years after mission completion.
De-orbiting faster means reserving more propellant for the final de-orbit burn. Since the lifespan of satellites is already generally determined by how much propellant they have, this new rule effectively reduces the lifespan of any satellite high enough to require a de-orbit burn.
Companies that use very low satellites are impacted less, since atmospheric drag does more of the work.
There's an externality to leaving a EOL'd satellite in LEO, now these new rules require that externality be priced in. Either through the cost of reserving enough propellant for a de-orbit burn, or perhaps, one day, for more expensive satellites, a new industry could emerge for refueling/boosting/servicing to extend the sat's life.
This regulation seems like a good sign that the commercial space industry is starting to mature in a healthy way.
In my view it's really a separate issue if SpaceX has too many advantages and that levelling the playing field somehow would be useful; allowing companies to grow too powerful does cause problems, and I don't think there's a moral requirement for regulators to be "fair" when dealing with corporations. They are not humans.
The need for that sort of intervention should not keep us from instating otherwise beneficial rules, though.
That's not what I was saying. I was offering an observation, not a critique. I think this new rule is good.
Read the article. It's about deorbiting after mission is finished.
If you have enough fuel on board you're free to keep your satellite for 50 years on the orbit. You just have to deorbit it within 5 after you stopped using it.
Does it apply to US satellite companies with ex-US launches?
Are US companies free to purchase service/bandwidth from ex-US launched satellites which are not compliant?
One new technology is releasing a sail to increase drag.
Example: http://www.parabolicarc.com/2021/08/23/millennium-space-syst...
Clearing out several satellites with one vehicle is not practical though, would need too much fuel. At best one might launch several such vehicles on one launch, or if orbital fuel depots really take off soon, it may be possible to have depots in convenient locations such that deorbiting vehicles can always make a relatively cheap visit to a depot to refuel and wait for another deorbiting target. In such a setup the deorbiter would just lower one end of the orbit to speed up decay rather than dragging it all the way down to Earth.
Among other things, they're promoting a standardized docking adapter (https://astroscale.com/docking-plate/) to give satellite operators a path to either life extension (refueling and/or orbit raising) or de-orbit.
But maybe there'd be some other way to do it? There have been proposals for de-orbiting little pieces of debris from the ground with lasers, and I suppose it's possible that those approaches would scale to bigger objects (or maybe you could do it with lasers from other satellites whose orbits were fixed, or something).
Avoiding splash-over or collateral damage to other sats in or near the line-of-sight would be an issue, especially if any of those other sats might have capabilities that their nation/owner might want to keep secret. Perhaps an arrangement of vetos over particular ablation shots would suffice. Countries wanting to hide their interests in some sats could veto N times as many shots as needed, making uncovering which sats are special more difficult.
In any case, laser ablation would need much less delta-V than the usual imagery of plucky space-cowboys chasing errant sats with a net, or some such. Who knew that _Planetes_ would have such a strong effect on our collective imagination.
Some companies approaching this problem are hoping to utilize refueling depots. It adds another expensive rendezvous but it does help.
https://www.cnn.com/2022/03/01/tech/space-junk-steve-wozniak...
If that's the case, then space junk removal is just a financial obstacle that will make it more prohibitive to launch new sats, and cause the business to move to other counties.
If anyone knows the specifics of how this would work, could you enlighten? Thanks!
If you're willing to forgo the US market you can jurisdiction shop... though I'd expect the Europeans won't be too far behind.
It's also not a really high bar. Most sats are in a regime where this happens naturally or already have propulsion. It's mostly going to bother SSO birds, and most of them are government owned anyway.
I guess if indeed it's not a big deal though, then probably not an issue to worry about. Thank you for your answer!
To have an effect you need to launch multiple orders of magnitude more mass than we have, and that mass would need to be optimized towards having as large as an effect as possible by being very very thin film positioned so that it is consistently between earth and the sun (or you could add on a few more orders of magnitude).
You can look at proposal for doing this intentionally to get a sense for the scale: https://en.wikipedia.org/wiki/Space_sunshade
Bus = 0.0002 km²
Earth = 510.1 million km²
(Earth / Bus) / 100 = 25,000,000,000 bus sized satellites needed to cover 1% of the sky.
I think this has to do with the amount of fuel the need to save to reach the disposal orbit.
The actual impact is probably small - there aren't that many satellites launching to those altitudes, and most of them probably have a propulsion system anyway. But for a university satellite this could be a big obstacle.
Or just add more drag. Like deploying big sail.
De-orbiting requirements add costs, but space junk damage and or avoidance systems are even more expensive, so this is the cheap solution in the medium to long term.
Eg. This spacecraft will act as a Comms satellite for 10 years and will then go into a low power mode where it switches to 'gamma ray burst detection mode' which will be active for 150 years, upon which it will then deorbit within 5 years as regulated.
1. Pretty easy to detect for most cases, especially as blunt in your (exaggerated, I know) example. Agencies should have a rough idea about realistic time frames for mission times in near earth orbits depending on what the satellite does.
2. They still need to have the propulsion unit integrated in the satellite, as otherwise they cannot guarantee the 5 years after mission time in higher orbits. They'll also need to prove that the propulsion unit used is very likely to actually work after mission time, e.g., your 160 year in radiation ridden space, which may be much more expensive than constructing one for the shorter, actual mission time.
While you might be able to find a country to let you pick your own rules, you will only be able to talk to your satellite which means you can't do much with it. Most satellite are used for communicating to people on the ground and if you can't communicate to the US the satellite is much less valuable.
...which has many post-Sputnik amebdments, but specifically the FCC role regarding policy for communication satellites comes from the Communication Satellites Act of 1962.