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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.
nonegatives says:
March 26, 2013 at 11:33 am
D.J. Hawkins says:
March 26, 2013 at 9:59 am
nonegatives says:
March 26, 2013 at 9:32 am
Where is Quark when we need him?
I’m not sure what use a Ferengi would be in this case. “Q” on the other hand could be a solution. Or not. He might just as likely turn all the debris into neutronium as clean it up.
Sorry, should have been more specific! Quark from 1978 – United Galaxy Sanitation Patrol
http://en.wikipedia.org/wiki/Quark_%28TV_series%29
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The other Quark, would contract out the work AND still make a handsome profit.
Lee Morgan at 11:26 asks “Aren’t they pretty near stationary with respect to each other? Because they’d be in different orbits if they weren’t?”
I think the question assumes that every piece of the debris is in a stable, long-term, circular and equatorial orbit. When you violate any of those assumptions, it is possible for two pieces of debris to be in their own orbits and yet for the orbits to cross.
The most significant failure in the assumption is that the orbits are all equatorial. That’s generally true for the geostationary satellites (and true to a lesser extent for the debris created by them) but it is untrue for the vast majority satellites which follow a circumpolar orbit. Circumpolar is what allows one satellite to map the entire globe as it rotates beneath it. Circumpolar necessarily means that those orbits are crossing at or near the poles. (Sinusoidal orbits will also cross but at different points.)
The second most significant failure is the assumption that the orbits are circular. The original satellites were (probably) put into a circular orbit but whatever accident turned them into debris probably also perturbed the orbit into an elliptical. It will be moving in and out relative to earth, gaining and losing speed as it does so and crossing the circular orbits (and other elliptical orbits) along the way.
The result is that, no, you can not assume the debris is stationary with respect to each other. They are quite dynamic. The only thing preventing them all from smashing into each other today is the vastness of space. Well, that and the fact that in a vacumn, a near miss is still a complete miss. It doesn’t matter whether you missed by a quarter inch or a dozen miles – there is no atmosphere to transfer any effect of a “near miss”.
In 2000, working as a Boeing engineer, I proposed the Boeing develop a company called Space Scavengers which would focus on several issues related to space junk. I have some experience with this topic as I spent one summer in the early 1970’s as an Orbital Analyst at NORAD (Air Force Academy third lieutanant program) where I performed orbital decays of space junk. A summary of my plan was to establish several initiatives concerning this problem. First, was the development of two small vehicles at the ISS named “Rover” and “Dolphin” . Rover’s mission would be to retrieve any object that broke free from the ISS. Dolphin’s mission would be to retrieve any astronaut who broke free from the ISS. Second, we need a space based interceptor based at the ISS that has the capability to seek out and destroy any junk that exists in the ISS’s orbital plane. Third, we need to investigate, as the technology matures, small, robotic,satellites that could “piggy-back” on another launch and then be deployed to retrieve high value space junk. These robots could use advanced propulsion systems and technologies to retrieve objects from as far away as geo-synchronous orbit. They could operate independently or as a unit to change the orbit of any satellite using solar sails/balloons/inflatible head shields/etc.. Finally, I proposed that we could eventually move into the rescue and repair business perhaps by locating a facility near the ISS. This proposal was quickly shot down by Boeing Space and Defense as an unworkable idea. I still have that proposal and it was interesting to dust it off and see that the problem hasn’t gone away.
The geostationary orbit is roughly 35,786 kilometres (22,236 mi) above the Earth. Satellites such as communications and weather satellites typically are in this orbit. Where a helio/Sun-synchronous orbit is 600 – 800 km above the earth. These make an orbit every 85 – 120 minutes. I believe these are the ones with the biggest risk from space debris as there is less “space” in the orbit.
To give an idea of how fast everything flies around in orbit, several years ago one of the Space Shuttles cracked a windshield while in orbit. The glass was at least two inches thick and was considered bullet resistant. Any idea’s what cracked it? A tiny piece of paint…
Leave it be. Earth looks after itself and the junk will be cleared out of orbit quite naturally. If we lose some satellites along the way, so be it. If we stop wasting quarter of a $million on every windmill, we’ll have enough to replace the satellites – no worries. 🙂
Leif Svalgaard says:
March 26, 2013 at 9:38 am
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Very few satellites have enough mass to make it through the atmosphere. Even then the few parts that do will be small enough to have pretty low terminal velocities.
_Jim says:
March 26, 2013 at 11:23 am
Including de-orbiting useful satellites still in service?
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Intact satellites would have a much higher mass to surface area ratio and wouldn’t be as strongly affected.
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?
@ur momisugly Gary D.
March 26, 2013 at 10:36 am
@ur momisugly Jean Meeus
How does higher solar activity increase air density above 200 kilometers?
As altitude increases, the atmosphere becomes thinner and drag lessens. The atmosphere is a gas and as it is cooled, it will contract slightly becoming thinner at a lower altitude. As it warms it Puffs up and becomes thicker at higher altitudes. As the Sun progresses to Solar Max it brings more energy to the atmosphere causing it to warm up and Expand outward (Puff up) to a cerrtain degree. This heat expansion causes increased drag at higher altitudes.
I would favor building an orbital factory/processing center in geosynchronous orbit or at one of the Libration/Lagrange points and send drones with a basket or scoop up front through the debris fields in large elliptical orbits so they pass into and then out of the fields on the outside and after several passes they have a full payload and then return to the processing facility. This would have many benefits besides cleaning up the junk. It would facilitate the colonization of the libration points and get humans into space in significant numbers, boost the economy just like the original space race did, and provide the needed stepping stone to Mars, Io, and Ganymede etc.
Does anyone know what happens to a cloud of gas if you launch it from an orbiting craft?
If such a cloud could be introduced into a high orbital plane (ideally traveling in the opposite direction to the debris) it might be a simple retarder/deorbiter…?
DesertYote says:
March 26, 2013 at 12:43 pm
steveta_uk says:
March 26, 2013 at 7:43 am
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?
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.
I think that classified military programs are usually 20-30 years ahead of what the public sees. For instance note the 747 that flew around with the impractical gas laser cannon for public demo, then suddenly the Navy is fielding ship based solid state high energy laser systems for missile knock down. That would make a fairly good case for a classified orbital laser system. Now such a system could just pull ahead of the debris and use the high energy lasers to de-orbit it through material out gassing of lower melting point material and some slowdown from laser reflection. However the military would (perhaps) have to admit to such systems.
My best conspiracy theory is that the military has very advanced flight propulsion systems under wraps (perhaps akin to those pesky UFO’s), but they will never go for public use because they don’t want “our enemies” (everyone but us) to have them. Now if some one like China were to quietly develop such systems commercially and then quickly put them in operation, they could pretty much own everyone.
All that useful material, in almost stable orbits, some of it in almost useful orbits – who the hell wants to de-orbit it? Surely better to attach say nanoscale robotic solar sails, launched from a HARP style ballistic launcher, guide the material to somewhere useful where it could be used for construction.
http://en.wikipedia.org/wiki/Project_HARP
At around $4000+ / kg launch costs, even small scraps are potentially useful, if a way can be found to guide them to where they are needed.
RHS says: March 26, 2013 at 8:35 am
“Q” says – Why not just change the gravitational constant of the universe?
No, that would adversely affect climate models.
Chris4692 says: March 26, 2013 at 9:19 am
… The thruster wouldn’t even necessarily have to slow it down or be immediate, just make its orbit more elliptical for more frequent contact with the atmosphere.
It would have to slow the satellite for the ellipse to dip to lower, denser altitudes.
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.
StanleySteamer says: March 26, 2013 at 1:40 pm
… I have some experience with this topic as I spent one summer in the early 1970′s as an Orbital Analyst at NORAD (Air Force Academy third lieutanant program) where I performed orbital decays of space junk.
Third Looie in a cave in the Zoo’s back yard? You must have p.o.’d somebody. I was back seat in F4’s in sunny Tucson. 😉
Matt says: March 26, 2013 at 10:19 am
Hire the Dyson corp to build a giant device to sweep up the debris and land it.
Or the Tyrell Corp.
I do like the idea of a Kevlar catcher’s mitt. We’ll need it to protect the space elevator, which will be getting full velocity impacts from anything that hits it.
MarkW says:
March 26, 2013 at 2:01 pm
Very few satellites have enough mass to make it through the atmosphere. Even then the few parts that do will be small enough to have pretty low terminal velocities.
http://www.edn.com/electronics-blogs/edn-moments/4405598/Satellite-scatters-radioactive-debris-over-Canada–January-24–1978
then continuing –
OH LOVELY; the charged dust is going to stick uniformly all over the satellite’s surface (including the solar panels) like flies on dog do-do, white-on-rice, IRS/tax collectors-on-taxpayers!
.
But this does not include a very useful and not so obscure set of sats such as:
GPS, Glonass or Galileo nav sats,
Iridium and Globalstar comm sats,
polar orbiting wx sats,
satellite broadcasters e.g. XM,
HAM (amateur) sats,
and the Orbcomm small data-packet comm sat constellation …
right off the top of my head …
.
OMG!!!!!
We’ve screwed up the planet and now space !!!
It is worse than we thought.
It is a serious problem though.
Powered or controlled de-orbiting involves legal liability under the laws of space treaty. If left uncontrolled, the launching country has a lower liability. Have the proponents of these concepts considered the laws involved?
Has any correlation been made between the number of satellites and global warming?
Re: atmospheric “puffing”
We saw this back during the solar minimum, when the troposphere contracted. While the total solar output doesn’t change much, the amount in the ultraviolet region dropped significantly, that might be the driver.
lsvalgaard says:
March 26, 2013 at 4:12 pm
MarkW says:
March 26, 2013 at 2:01 pm
Very few satellites have enough mass to make it through the atmosphere. Even then the few parts that do will be small enough to have pretty low terminal velocities.
http://www.edn.com/electronics-blogs/edn-moments/4405598/Satellite-scatters-radioactive-debris-over-Canada–January-24–1978
We can hope for more of them to fall into the ocean?
Russia’s Failed Mars Probe Crashes Into Pacific
By ANDREW E. KRAMER
Published: January 15, 2012
. A Russian scientific probe that was meant to visit a Martian moon but never made it out of Earth orbit crashed into the Pacific Ocean about 700 miles west of Chile on Sunday, a Russian military spokesman said.
The Phobos-Grunt spacecraft had been circling Earth since shortly after its launching on Nov. 9, losing a few miles of altitude each day until it fell into the atmosphere. The 13-ton ship was one of the heaviest manmade objects yet to make an uncontrolled plunge back to Earth, though most of its weight was fuel and probably burned up during re-entry.
..As Phobos-Grunt broke up and burned on re-entry, the Russian space agency said, as many as about two dozen pieces might have reached the surface, weighing a total of about 400 pounds. …
http://www.nytimes.com/2012/01/16/science/space/russias-phobos-grunt-mars-probe-crashes-into-pacific.html?_r=0
One of the big problems is how do you intercept something that is so small and moving so fast that it is almost impossible to track with a reasonable sized on orbit sensor. If you can do that, there is at least one class of material that could be de-orbited without any additional generation of debris. Any magnetic or para-magnetic material could be slowed down by passing it through a strong magnetic field on closest approach to the capture device.
For example a large tubular device about the size of a shuttle fuel tank with strong electro magnets positioned so the debris item passed down the axis of the device, on the inbound side of its elliptical orbit toward perigee. A piece of aluminum for example would be strongly slowed as it passed through the magnetic field inside the device. Iron would have to have the magnetic field activated only after the debris object is near the center of the device so it only would see deceleration as it moved out of the capture device.
The bad news is this is probably not logistically or financially possible but in theory would work.
A similar approach for a “catchers mitt could be devised for non-magnetic or non-para-magnetic materials like paint chips or plastic. It would have to be a deep cylinder perhaps tapering with multiple thin membranes across the tube with a dead end able to survive final impact. In effect you would be have a very deep whipple shield contained inside an open ended “trash” can. Sort of a roach motel for orbital debris, it checks in but does not get back out. Each successive membrane impact would deplete energy and break up the object into small enough pieces it can be contained inside the can. To prevent the generated debris from exiting the can, you would have two methods at work. First the debris would have to find its way back out through all the membranes by passing through one of the holes generated by previous impacts. This would be geometrically difficult, odds of a bit of generated debris being on the right flight path to pass back out one of these small openings would be very small. The other would be inertial capture, by having the “trash can” accelerate briefly shortly after the impact so that the debris “falls” to the bottom of the can, and becomes more stuff that a newly arriving piece of space junk could impact to shed velocity.
Again possible for certain objects of high concern, but probably too expensive to be economically affordable, and the logistics overhead of managing even a single capture would involve a lot of people and data processing capability.
No easy fix on this one but it could be done with enough will and investment of time and resources.
Larry
Leo Morgan says: March 26, 2013 at 11:26 am
I’d love to know the figures they used. It’s not that I doubt the figures; I just don’t know them, and it’s interesting stuff. There are many thousands of sattelites there, but there are also many millions of cubic miles of empty space.
Aren’t they pretty near stationary with respect to each other?
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As an example, assume you are on the ISS at 400 km altitude and you release a satellite with no relative velocity. Six months later that sub satellite will be in an orbit far different from ISS. Because the ballistic coefficients are different, atmospheric drag will have moved the two objects into different orbital planes and slightly different altitudes. I worked on the now-cancelled Orbital Maneuvering Vehicle (OMV) which was supposed to release and fetch just such satellites. We learned that after a few months, no reasonable space “tug” could go get the released satellite. If the orbits intersected then, the relative velocity would be several hundred meters/sec, quite enough to destroy both vehicles.
As for the atmospheric drag question, ISS needs reboost multiple times per year, and this is done with the docked Soyuz or Progress tankers. Skylab was supposed to be rescued (reboosted) by using the new Space Shuttle, but Solar Max raised the atmosphere which increased drag more than assumed. That plus delays in the Shuttle program combined to lose that big space station.