A few problems holding a solution like that back right now:
1) It takes a ton of fuel to change your orbit once you're in space, and space is _really_ big (even just the orbital ranges we're talking about). It's just not currently feasible for a ship like that to capture debris and then use _more_ fuel to bring it back down.
2) Relative velocities of some debris are so large (and they are so spread out) that it's not yet feasible to capture it and bring it back with any current approach.
Dead satellites are mostly dangerous for the scattered debris they _might_ become if something hits them/they bread up. So while bringing them back is important, it's not as immediate a danger as things that have already broken up.
Basically, we don't have any approach that would make a major difference, even if money was no object (which it is).
It's not even close to feasible IMO. These pieces of debris are traveling many times faster than bullets and they have significant mass. They would rip aerogel to shreds. You would need square kilometers of bulletproof armor. Imagine a project to catch all the fish in the ocean except the ocean is a million times bigger, the fish are going as fast as bullets, and every fishing trawler costs a billion dollars. And you can't sell the fish to fund it.
Retrieving whole defunct satellites is possible but only one or two at a time because of the huge amount of fuel needed to match orbits with each one. And once you've grabbed one it takes even more fuel to de-orbit it (which you'll notice didn't happen here). Don't forget that every maneuver you make as a spacecraft has to use extra fuel just to haul all the fuel for every future maneuver you'll ever do, and that compounds for every lifetime maneuver.
It's worthwhile to dispose of old satellites so they don't collide and produce debris clouds that are basically impossible to clean forever, but it's not funded.
There are other attempts at disposal of dead satellites that don’t rely on a long-shot like the BFR [1]. Besides, maneuvering a big heavy spacecraft like that to match orbits with a bunch of little satellites would be tremendously wasteful in terms of fuel. A much better use would be to remove larger satellites like defunct communications satellites. These are actually a much bigger danger to orbital space as well. See this event for example [2], which generated over 2000 pieces of debris large enough to track and many more of a smaller size. Small satellites are not nearly as dangerous because when they are defunct their low mass causes them to renter faster.
(FYI I’m a PhD student in the lab that built the satellite in the article.)
Maybe it would be time to have a global agreement that all satellites must implement the means of "disposal re-entry" so they can be taken out of the space scrapyard and safely (as much as possible anyway) crashed to earth.
The amount of debris in space is going to be a problem that's going to be both costly to solve and very detrimental to future space systems if we continue to not do enough about it.
There's no incentive to me to make my satellite safely de-orbit before it gets broken into pieces. So why would I bother? That's expensive.
But like all 'easy to litter, hard to clean up' problems of this nature, we have a solution already: require a cleanup deposit ahead of time that will be returned to whoever cleans it up.
All space-launching countries should sign an accord that said something along the lines of "Every satellite must have a deposit to the international Kessler Fund", say something like $X/kg, inflation adjusted. Companies would spring up with the sole purpose of de-orbiting defunct satellites. Launch would become more expensive, yes, but soon every bit of metal in space would come equipped with a plan for how we're getting it out of orbit.
Well, the stuff is there right now, but there’s nobody harvesting them because it’s nowhere near economically viable. Maybe someday in the future, but we can’t just keep polluting the orbits while waiting for that hypothetical day.
LEO stuff is going to deorbit due to drag anyway sooner or later, and we very much would like that to be ”sooner”. Higher orbits are stable for a long time, and intentional deorbiting is not feasible anyway due to the amount of delta-v needed. So there are ”graveyard orbits” into which satellites should be moved before they’re out of propellant.
Anyway, intercepting and capturing defunct satellites on a large scale would be surprisingly costly because of the large variety of orbital planes involved. Inclination changes are expensive with regard to delta-v!
I don't think there would be any hope of actually collecting the bits piece by piece, the amount of fuel required to match trajectories alone makes it infeasible. The best 'solution' would be to change the trajectory of the garbage either away from the atmosphere, or into the atmosphere. Unfortunately a lot of it won't completely burn up before it hits the ground, creating a few more problems then just some broken satellites.
How would that work? A rocket launches into orbit an unmanned satellite capable of autonomously intercepting the orbit of debris in order to collect it and then deorbit itself? Seems extremely expensive for little benefit.
It's my understanding that atmospheric drag and orbital perturbations due to the gravity of other celestial bodies cause satellites to need station keeping maneuvers just to avoid crashing into the Earth. So it seems to me that this debris problem will eventually take care of itself.
This works great for a small-subset of the space-debris problem: satellites in low-earth orbit that have reached their end-of-life. For example, Starlink satellites maintain a small reserve propellant for their maneuvering thrusters to be executed at EOL. This activity will likely be mandated by regulatory bodies in the coming years (and definitely should be). However performing this task becomes much more difficult to do as orbits get higher. The higher the orbit, the more fuel is required to perform a de-orbit, and the more fuel is required to lift THAT fuel into the orbit in the first place. Propellant requirements scale exponentially with increased mass. Beyond a certain orbital altitude, it becomes prohibitively expensive.
In addition, the bulk of the space-junk problem is not defunct satellites, but fragments from previous collisions, and stage-separations (screws, scraps, paint-chips, etc). Satellites (even defunct ones) are easily trackable, and have known trajectories. Random 10 cm pieces of metal are not.
While mandating EOL maneuvers for low-earth satellites is definitely a solution to part of the problem, it is not the full solution.
IMO we need to stop putting satellites in orbits above ~800km altogether. No matter how careful you are there will always be accidents, and once a collision or explosion occurs in high orbit the debris is essentially a permanent fixture of the solar system, lasting far longer than a human lifetime. There is no feasible method to clean up such collision debris for the foreseeable future. Even assuming SpaceX Starship is wildly successful and launching a thousand times more mass to orbit for dirt cheap, collision debris cleanup is still infeasible. The only realistic way of cleaning collision debris is the natural way, the atmosphere. But it only works on reasonable timeframes when you're below a certain altitude.
Luckily the reasons why we used to launch satellites into high orbit are mostly obsolete now. We did it for three reasons: firstly so the satellites would last longer because they are expensive, secondly to get higher land area coverage from fewer satellites again because satellites are expensive, and thirdly to make it possible to use stationary or slow-moving satellite dishes. Now that launching satellites is much cheaper and likely to get even more so, the first two reasons are obsolete. The third reason is made obsolete by modern phased array antennas that can be pointed without moving. So we don't need to take on the debris risk from high orbiting satellites anymore.
Yeah of course, de-orbiting or grave yarding a single piece of debris is doable for a few million dollars right now, but we are talking about a large fraction of 900K+ pieces. That's the really hard part.
It's not big satellites in controlled orbits that are a major problem from a space junk standpoint. Mostly it's the smaller fragments that are the problem, which outnumber satellites by a huge margin. Besides which, the easier it would be to launch satellites into orbit the easier, and cheaper, it would be to launch programs for cleaning up debris and abandoned satellites.
The solution for this problem is relatively simple. Satellites should be put in low orbits. A satellite collision in high orbit is practically irreversible and will pollute space essentially forever. A satellite collision in low orbit is automatically cleaned up by the atmosphere, over a period of years to months to days depending on the orbit height.
In the past it was not practical to put satellites in low orbit for several reasons. One, because the same atmospheric drag that cleans up debris would pull the satellites out of orbit too, severely limiting their useful life. Two, because a satellite in low orbit can only see a small part of the Earth's surface at once and passes over it very quickly. You can't use satellite dishes to communicate with such satellites, and establishing continuous coverage over any part of the Earth's surface would require hundreds or thousands of satellites.
Two things have happened that changed the game. One, phased array antennas are now cheap enough for consumer applications and they are able to communicate with multiple fast-moving satellites at once without physically pointing at them. Two, SpaceX has decreased launch costs to the point where it is now feasible to launch thousands of cheap satellites instead of dozens of expensive satellites, and replace them all within a few years instead of expecting them to last for decades. Starlink satellites orbit at 550km where debris lasts only a few years before automatically being cleaned up by the atmosphere. Future generations may orbit even lower where debris is cleaned up even quicker.
The non-SpaceX proposals for large constellations mostly chose higher orbits. I think it's time to prohibit this. Starlink competitor OneWeb just had a satellite failure at 1200km and that dead satellite will pollute orbit for centuries if it is not retrieved (and there is no realistic plan to do so, nor proper incentives to ensure that it happens). Heaven forbid that it collide with something and produce a debris cloud that can never be fully cleaned up in our lifetimes. Meanwhile, Starlink has had tens of failed satellites and they are all deorbited already or well on their way. It just doesn't make sense to do things the "old space" way with a small number of expensive high orbit satellites. Low orbit cheap satellites are the future.
Hi HN, we're Ryan, Tyler, and Patryk, the founders of Turion Space (https://www.turionspace.com/). We're building spacecraft to remove orbital debris and provide services to existing satellites.
Orbital debris poses a significant risk to mankind's future in space. There are currently over 250k objects in space that would destroy a satellite if a collision were to occur. Large uncontrolled objects like depleted rocket upper stages and dead satellites pose the greatest risk because of the potential to break upon impact with small debris into thousands of smaller pieces. There is currently no system in operation that can deorbit large amounts of space debris. If this problem is not addressed in the next 5-10 years, it could render entire orbits unusable for generations.
Our spacecraft (which we’ve decided to call the “Droid”, shoutout to Star Wars!) aims to remove debris by docking with it using robotic arms and dragging the debris to a lower orbit using the ion propulsion system we are developing under a NASA technology transfer license. Once the debris is in a low enough orbit, upper atmospheric drag will cause the debris to naturally decay in altitude until it burns up during atmospheric reentry. Critically, the Droid would undock with the debris after dragging it to a low orbit, then orbit-raise, and go on to perform other missions. In other words, our solution is a reusable approach, designed from the beginning to complete multiple missions during its lifetime.
Our team encountered this problem when brainstorming ideas to answer the question, "with the rapidly declining cost of getting things into space, what can we do now that has never before been possible?" Asteroid mining seemed like the obvious answer, but the capital required to start a business on that premise seemed like a longshot to say the least. We found the most important problem we could solve while building the foundation to asteroid resource extraction was to create a satellite system capable of removing orbital space debris.
Our team has extensive experience working on operational space flight hardware and building software products from the ground up. Ryan comes from an 8.5-year run at SpaceX, working primarily on propulsion development and dynamics analysis of the Merlin, Superdraco, and Raptor engines. Tyler comes most recently to ATA engineering, working as a consultant for various aspects of thermal, structural, and dynamics analysis across a wide range of now-operational space-flight projects. He also worked at Electroimpact, where he designed and built aerospace-assembly-automation systems using robotic arms. Patryk comes most recently from Marshall Reddick real estate where he developed the company’s in house CRM that was vital to the company's growth over the last 5 years.
We expect to begin servicing sometime in 2024. We have gained interest in several use cases through conversations with customers to complement our orbital debris removal efforts, beginning with low-earth-orbit operations. For low-earth-orbit satellite operators, we can raise their altitude or modify the inclination of their orbit. We have also partnered with launch providers to expand their mission capabilities by offering our last mile tug service for their payloads. For example, suppose a small launcher can only lift a 200 kg satellite into a 500km orbit altitude, but that payload wishes to end up at a 1200km altitude. In that case, we can dock with the payload once it has been deployed from the launch vehicle and bring it to its final orbit.
Check out the services section of our website at https://turionspace.com/satellite-tracker and track satellites or get pricing estimates for different mission scenarios! We'd love to hear feedback and chat about orbital debris removal!
It's not big satellites in controlled orbits that are a major problem from a space junk standpoint. Mostly it's the smaller fragments that are the problem, which outnumber satellites by a huge margin. Besides which, the easier it would be to launch satellites into orbit the easier, and cheaper, it would be to launch programs for cleaning up debris and abandoned satellites.
In fact, if launch were significantly cheaper then Earth orbiting satellites could be equipped with special sub-systems designed to deorbit them if the main satellite became inoperable.
This debris is probably actually pretty cheap to remove by chance.
The orbit it is in is perfectly between geostationary and the disposal orbit. That means any other satellite who is travelling from one orbit to the other can stop off on-route for no fuel or time cost.
'grabbing' a satellite is fairly easy too. Even a fridge magnet would be enough to grab this satellite - since even tiny forces over many hours are enough in space.
I therefore suspect that it would be possible to complete this disposal with a satellite already on orbit - ie. not specially designed for the purpose, and using very little additional fuel - perhaps some operational satellites even have enough extra in reserve.
The vast majority of new satellites are being placed into low earth orbit, which is cleaned up fairly quick by atmospheric drag. You can see this on an animated Gabbard diagram: https://www.youtube.com/watch?v=aRUaENzxH44
In higher orbits, particularly GEO (like the satellite in question), it's much more of a problem. Laser brooms might one day be used to deorbit small pieces of debris, but dead satellites beyond LEO will need to be grabbed and tugged/thrown into safer orbits.
1) It takes a ton of fuel to change your orbit once you're in space, and space is _really_ big (even just the orbital ranges we're talking about). It's just not currently feasible for a ship like that to capture debris and then use _more_ fuel to bring it back down.
2) Relative velocities of some debris are so large (and they are so spread out) that it's not yet feasible to capture it and bring it back with any current approach.
Dead satellites are mostly dangerous for the scattered debris they _might_ become if something hits them/they bread up. So while bringing them back is important, it's not as immediate a danger as things that have already broken up.
Basically, we don't have any approach that would make a major difference, even if money was no object (which it is).
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