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Removing orbital debris with less risk
Global Aerospace Corporation (GAC) announced today that the American Institute of Aeronautics and Astronautics (AIAA) is publishing an article entitled “Removing Orbital Debris With Less Risk” in the March/April edition of the Journal of Spacecraft and Rockets (JSR) authored by Kerry Nock and Dr. Kim Aaron, of GAC, and Dr. Darren McKnight, of Integrity Applications Incorporated, Chantilly, VA. This article compares in-orbit debris removal options regarding their potential risk of creating new orbital debris or disabling working satellites during deorbit operation.
Space debris is a growing problem in many orbits despite international debris mitigation guidelines and policies. While this space environmental issue has been discussed and studied for years, many critical parameters continue to increase. For example, the number of significant satellite breakup events has averaged about four per year. Removing large amounts of material already in orbit has been a major issue for debris mitigation strategies because a large object, like a satellite or spent rocket stage, is not only more likely to be involved in an accidental collision due to its large collision cross-section but the large mass has the potential to be the source for thousands and thousands of smaller, but still dangerous, debris if involved in a collision.
Deorbit devices have been proposed for dealing with the growing problems posed by orbital debris. The authors describe these devices that can use large structures that interact with the Earth’s atmosphere, magnetic field or its solar environment to deorbit large objects more rapidly than natural decay. Some devices may be better than others relative to the likelihood of collisions during their operation. Current mitigation guidelines attempt to address this risk by calculating an object’s atmospheric drag area times its orbit decay time to compare the probability of a large object experiencing a debris-generating impact. However, the authors point out that this approach is valid only for collisions with very small debris objects. Since the peak in the distribution of the area of orbital debris occurs for objects with a size close to 2 m, some of which are operating satellites, it is important to incorporate an augmented collision cross-section area that takes into account the size of both colliding objects. This new approach leads to a more valid comparison among alternative deorbit approaches.
Two other factors that affect the potential risk of a particular deorbit device are the nature of hypervelocity impacts and the level of solar activity. The authors describe the physics of hypervelocity impacts in space that can affect the assessment of risk. In addition, they describe how solar activity level affects the decay process and alters the result of the calculation of collision cross-section area times decay time, which is a measure of the risk of the deorbit device. The authors also characterize two types of collision risk, that is, the risk of creating new debris-generating objects in hypervelocity impacts by high-energy collisions and the risk of disabling operational satellites by low-energy collisions.
The implication of this new approach to determining risk indicates that ultra-thin, inflation-maintained drag enhancement devices pose the least risk of creating new debris or disabling operating satellites, while electromagnetic tethers are shown to have a very large risk for disabling operating satellites. All deorbit devices studied appear to have less risk than leaving an object in orbit even for only 25 years, which may suggest a possible need to reconsider current orbital debris mitigation guidelines that allow objects to remain in orbit that long.
“As the orbital debris hazard increases, it will be critical that the community can use techniques that have high operational effectiveness and low risk. Inflatables have been the best balance for that approach in my mind and I hope that this paper exposes more of the aerospace industry to the benefits of using inflatables to accelerate the reentry of non-operational spacecraft,” said Dr. McKnight.
Finally, atmospheric drag deorbit devices are found to be much more efficient during periods of high solar activity and therefore pose a lower overall risk. Permitting a satellite to use a smaller drag device over 25 years, which will average about two solar cycles, means it will incur about three times the risk compared with a larger device selectively operated near solar max (including the time taken waiting for solar max). As a result, the authors recommended that drag augmentation devices be sized and timed to complete their deorbit function only during solar max in order to further reduce the risk of creating new debris.
I’d go with the factory idea. We spent a fortune getting the stuff up there and letting it go to waste is silly. It is so much cheaper to change orbits than to get the new stuff up there.
There was a book years ago where this was the central characters main job, going out and getting the old boosters and satellites to be melted down and reworked to extend the station. Damned if I can remember the name but the craft used was nothing more than motors, fuel, a computer to work out and control the burns and a seat for the pilot.
It’s also worth while to remember that those sats which failed early in their lives probably still have full fuel tanks for their thrusters. Might it be possible to use the fuel from dead sats to refuel some of the good ones and extend their lives?
Such a facility would be expensive, but launches are worth over $200 billion per year now. Note that the same craft used to recover junk could rescue a sat that failed separate from the booster and place it in the correct orbit. Paying the station to do that would be far cheaper than paying for a new sat and launch. So the station gets the recovery fee and a nice new booster for fresh materials as well.
Bill Parsons says: ‘Usually we don’t watch movies mid-week, but I saw the movie “October Sky” last night. Homer Hickam later wrote his own biography, “Rocket Boys”, …’
Other way around — the movie was based on Hickam’s book.
I spent several years working on a project for the Department of Defense on the implications of space debris for satellite life in low earth orbit, (100 miles). Since the days of Sputnik we and others have added steadily to the flux of debris traveling around the earth at hypervelocities, 10 to 20 km/sec. The debris is not aligned indirection and can be in counter directions. The picture is very misleading because the velocity distribution of particles is varies with latitude and longitude and the spacing is very sparse. Large particles are being tracked and monitored. Several times the space station was moved slightly to avoid a collision with space junk.
I doubt that anyone would able to come up with an inexpensive way to capture or de-orbit the very small pieces of junk. The LDEF satellite which spent several years in orbit before it was rescued by the space shuttle has impacts on numerous surfaces from small particles of debris but none were catastrophic. Probably space junk is not a major problem facing the space program when one considers that the size of the NASA budget continues to shrink. Since the likelihood of a major collision with a satellite is low, when it happens it might be cheaper to replace the satellite than to launch a vehicle to collect space junk.
steveta_uk says: “What about all the super-secret satelite killing lasers that the military have secretly been putting into orbit since the 1980′s? Can’t they be used to vaporise the garbage?”
DesertYote says: “… The energy that is absorbed goes into vaporizing small amounts of material that push the target into new orbits.”
That’s the intended result of the laser. Zapping an approaching bit of debris with a ground-based laser vaporizes a layer of the target which, per Newton’s 3rd, gives it a slight de-orbiting burn.
http://en.wikipedia.org/wiki/Laser_broom
MarkW says:
March 26, 2013 at 2:10 pm
DesertYote says:
March 26, 2013 at 12:43 pm
Ok, I’ll bite. Won’t work. At best just make a bunch of smaller junk. Spaced based laser systems also have the nasty habit of deorbiting every time they are fired. The shiny metal surfaces of much space junk also tends to just reflect more energy the absorbed. The energy that is absorbed goes into vaporizing small amounts of material that push the target into new orbits.
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What about a lower powered laser fired in such a way that the debris is slowed down?
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The laser wielding killer satellite would still have to deal with its change of momentum caused by changing the momentum of the target, but this is getting closer to a workable system. Also note that the killer would be pushed into a higher orbit and the target into a lower, so the target would be over taking the killer at some point ( change is perpendicular to the axis of force, vector multiplication and all that).
Kirk to Scottie,
“Don’t beam me up Scottie”
US Government mitigation standard practices call for maneuvering to limit orbital lifetime to 25 years after the end of the mission when possible. NASA has been requiring this for its maneuverable satellites below an altitude of 2000 km since 2007. GEO birds must be shifted to a graveyard orbit at end of life.
An impact risk assessment for any components which might survive reentry is required as part of the design process. That risk has to be tiny, in accordance with established criteria.
The problem is, what do you do about all the debris which is already up there? And, how do we deal with the potential of a cascade effect, in which one collision creates a much broader cross section for impact, leading to additional impacts, and so on, and so on…
Many years ago it was proposed to destroy icebergs in shipping lanes by spreading carbon black on their sunlit surfaces to melt them.
http://www.navcen.uscg.gov/?pageName=photoGallery&photoGalleryId=4
This proved ineffective as the icebergs tended to roll as they melted and their balance changed.
However a similar idea was later floated for the deflection of incoming comets. In this small rockets fly to the comet and detonate ahead of the comet and spread carbon black over its surface. Heliostat arrays in earth orbit then focus intermittently on the comet and use the boil off of ice as propellant to deflect the main mass of the comet. However it was later found that most comets already have a dark surface.
It may be possible to reuse some of these ideas to de-orbit space debris. An orbital heliostat mirror array has far more potential power than any laser currently available. Most high powered missile destroying lasers are gas lasers that require consumables. A heliostat mirror array is powered by the sun.
A better use of available consumables payload would be dark ice balls. Rather than firing the mirror array at the debris directly (which would likely cause secondary fragmentation), it could be focused just ahead of the debris along its orbit. Ice balls of frozen water and black dye could then be fired into the focus. The resulting steam explosion would alter the velocity of the approaching debris. These steam explosions could be used multiple times on larger elements and altering focus and detonation points could allow trajectory adjustment of the debris. Aiming the mirror array and ice balls would not require the precision or sophistication of rockets that intercept and attach. Any un-vaporised ice balls and fragments would soon vaporise in sunlight due to their black dye without adding to materials in orbit. Such as system could be used against a wide range of targets.
The removal of the smallest particles may have to wait for the increased drag of an atmosphere expanded to near pre 2000 levels which should occur again some time after 2035. Sorry Leif 😉
Leif Svalgaard says:
March 26, 2013 at 9:38 am
If it is the case that control of the point of impact is so critical, how do the other methods, which are designed to slowly decay the orbit over many years, control the point of impact?
Chris4692 says:
March 26, 2013 at 9:43 pm
If it is the case that control of the point of impact is so critical, how do the other methods, which are designed to slowly decay the orbit over many years, control the point of impact?
Read here about de-orbit strategy http://esamultimedia.esa.int/docs/gsp/completed/comp_i_01_N13.pdf
Bill Woods says:
March 26, 2013 at 8:36 pm
steveta_uk says: “What about all the super-secret satelite killing lasers that the military have secretly been putting into orbit since the 1980′s? Can’t they be used to vaporise the garbage?”
DesertYote says: “… The energy that is absorbed goes into vaporizing small amounts of material that push the target into new orbits.”
That’s the intended result of the laser. Zapping an approaching bit of debris with a ground-based laser vaporizes a layer of the target which, per Newton’s 3rd, gives it a slight de-orbiting burn.
http://en.wikipedia.org/wiki/Laser_broom
###
My comment was about the infeasibility of vaporizing the target. I address some points related to using lasers to deorbit the target in another comment. One difference between ground based lasers and space based, is that with ground based, the “equal but opposite” accelerates the earth, which only a climate scientist would be able to detect, while a space based would accelerate the platform … that whole conservation of momentum bit. Doesn’t matter that the momentum is being carried by photons; photons, electrons, atoms, all the same.
Electromagnetic tethers are the only viable and cost effective method of deorbiting these satellites. The problem is not technical but legal. Most of the debris out there is of Russian origin and the Russians will not give permission to access their property.
lsvalgaard says:
March 26, 2013 at 11:49 am
Leif, thanks for your reply.
While you were at that wiki page I hope you looked at the jpg of the collected debris being reconstructed in a hangar. I saw two large objects: the axle of the front undercarriage, and some large-ish round shiny thing from the nose. They might possibly have caused substantial damage if they landed in a built-up area — wrecked a house for example.
Thousands of meteorites fall out of the sky every day. At a terminal velocity of 200 km/h, some are large enough to kill any human they hit. I’m scratching my brains to think of the last time I heard of anyone killed or even injured by a meterorite!
oldfossil says:
March 27, 2013 at 5:37 am
I’m scratching my brains to think of the last time I heard of anyone killed or even injured by a meterorite!
Stop scratching: Chelyabinsk
Safe de-orbiting is a real issue that is taken seriously:
http://esamultimedia.esa.int/docs/gsp/completed/comp_i_01_N13.pdf
DesertYote says: “… One difference between ground based lasers and space based, is that with ground based, the “equal but opposite” accelerates the earth, which only a climate scientist would be able to detect, while a space based would accelerate the platform … that whole conservation of momentum bit. Doesn’t matter that the momentum is being carried by photons; photons, electrons, atoms, all the same.”
The momentum of photons is pretty trivial. While it’s firing, a 1-MW laser would experience a recoil of only 3 mN, and the most it could deliver to a target is twice that. The way to really move the target is to heat its surface enough to blow off a thin layer.
From the looks of it, it going to be simpler & (perhaps several orders of magnitude) cheaper to just ignore the debris & launch a new satellite when one of ’em gets mashed.
In the case of a[n already] massive waste of money like the ISS, we can track & de[stroy|orbit] anything that seems like it might cause specific problems there.
Mike McMillan says:
March 26, 2013 at 3:46 pm
Mac the Knife says: March 26, 2013 at 12:32 pm
… The cost to launch all of that now obsolescent hardware probably averaged $10,000/lb delivered to orbit or more …
Once the velocity of money picks up, inflation from all this insane deficit spending will be upon us and $10,000/lb will be the price of steak.
Mike,
I whole heartedly agree with you on the insanity of our huge deficits, national debt, and ‘buying’ our own Treasury issued bonds/bills/notes with unsupported, newly printed ‘money’, because the rest of the world will no longer buy all of our debt! We are ‘monetarily easing’ our way into bankruptcy, with Russia,China, and Iran cheering us on.
However, the past investments in mass launched to orbit (roughly $10,000/lb) is a done deal. The looming inflation will increase the dollar cost of that investment, much the same way it has increased/inflated the dollar cost of gold over time.
From a pragmatic and historic perspective, those orbiting boosters and satellites are potential gold mines on the new frontier! What we learn about the economics and practicality of mining these resources in near earth orbit will provide the lessons learned necessary to take the ‘next step’: Capturing and setting up mining and manufacturing operations on high metal fraction asteroids.
MtK
***
oldfossil says:
March 26, 2013 at 10:58 am
The Chelyabinsk meteroid had an estimated mass of 11 metric tons with a solid quartz structure that resisted burnup.
***
It’s about speed. Meteors are far faster than orbital stuff, so burn-up of a given mass is much more likely for a meteor than a piece of spent-rocket.
Bill Woods says:
March 27, 2013 at 10:41 am
DesertYote says: “… One difference between ground based lasers and space based, is that with ground based, the “equal but opposite” accelerates the earth, which only a climate scientist would be able to detect, while a space based would accelerate the platform … that whole conservation of momentum bit. Doesn’t matter that the momentum is being carried by photons; photons, electrons, atoms, all the same.”
The momentum of photons is pretty trivial. While it’s firing, a 1-MW laser would experience a recoil of only 3 mN, and the most it could deliver to a target is twice that. The way to really move the target is to heat its surface enough to blow off a thin layer.
####
Sorry for taking so long to reply. I’ve been rather sick. Don’t get me wrong. I was not discounting the viability of using space based lasers to deorbit junk, as I indicated in my first comment on this subject. I was just pointing out the fact that firing a laser would change the orbit of the lasers platform. BTW, a laser used in this way would be a pulsed laser and not continuous fire which simplifies some things but makes others more complicated. Regardless, the platform would have to be very maneuverable or else it would be useless for the task. I’d love to write the targeting software.
30 years ago I thought we were going somewhere with space exploration and exploitation, where we are today is a bit sad.
Maybe the private boys will succeed, I sure hope so, as all we can do right now is cower at the bottom of this gravity well and pray the asteroids keep missing.
Very similar to the way we cower in fear from the group psychosis of the eco-doom religions.
Thanks WUWT, without this help I would still be afraid that the collective was nuts, rather than a loud mouthed minority.
There’s a trash hauling outfit in Passaic, NJ…the Marucci Brothers…that’ll do the job for a small fee. They’ll get some trucks and containers up there and take care of the problem…capish?
Stark Dickflüssig says: “From the looks of it, it going to be simpler & (perhaps several orders of magnitude) cheaper to just ignore the debris & launch a new satellite when one of ‘em gets mashed.”
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The trouble is that collisions between debris & satellites, and debris & debris, generate *more* bits of debris. The end result could render low Earth orbit too dangerous to use.
http://en.wikipedia.org/wiki/Kessler_syndrome
NASA and MDA (current owner of the Canadarm manipulator product used on the space shuttle and international space station) have toyed with developing robotic equipment to repair satellites (in effect unmanned space devices).
Should be usable to grab defunct satellites to get them out of orbit, but need a sizeable bag to hold them?
Size of pieces varies of course, from whole satellites to very small pieces that still endanger active satellite – need special method for those?
I do like the concept of keeping the mass in orbit by somehow re-using it, but that takes processing to separate materials, which takes a facility. That’s costly, even more so with quantities of humans who require life support systems.
Owners of active satellites should be happy to pay to get rid of the debris they have to maneuver their satellites around.
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