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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.
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”, about his experience growing up in Coalwood, Virginia, and sudden interest in rockets after watching Sputnik, the first man-made satellite, crossing overhead one night.
http://en.wikipedia.org/wiki/Homer_Hickam
Sputnik was launched in 1957, and came down three months later, in January, 1958. We’ve come a long way to create the cluttered mess pictured above.
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.
Hire the Dyson corp to build a giant device to sweep up the debris and land it.
A not-so-insignificant amount of that debris is owed to ‘packages’ that exploded late in the procedure of getting them into their planned orbit, as in the 3rd or last stage simply blew up. Nothing left but an expanding, orbiting “debris” field after an event like that …
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@ur momisugly Jean Meeus
How does higher solar activity increase air density above 200 kilometers?
>the graphic is somewhat misleading
“REPLY: that’s dealt with in the caption, maybe you missed it – Anthony”
Yes, I did miss it although my comment was directed at the originator of the graphic who I know can be misleading. That’s the part you missed because you can’t read my mind.
Lot of precious metals in the debris: copper, gold, platinum, etc ….
Larry Page with Eric Schmidt of Google, and “Avatar” director James Cameron could find more profitable hoovering this space junk than their odd enterprise to chase and mine asteroids.
Doug Huffman says:
March 26, 2013 at 8:46 am
Are the units of collision cross-section Barns, as subatomic absorbtion cross-sections are, equal to 10^-24 cm^2 as I recall? Two related units are the outhouse (1 μb, or 10^−34 m^2) and the shed (10^−24 b (1 yb), or 10^−52 m^2)
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And of course there are the units most interesting for weather folks….the milli-barn
(sorry…)
Leif Svalgaard says:
March 26, 2013 at 9:38 am
Yes, Leif, but how large would a satellite have to be to impact the ground? The Chelyabinsk meteroid had an estimated mass of 11 metric tons with a solid quartz structure that resisted burnup. The Columbia shuttle had a mass on re-entry of about 100 tons and even massive parts like the engines didn’t reach the ground intact.
Years ago, I did work on effects of nuclear explosions in space. One of the major effects was something called “atmospheric heave” whereby the energy deposited in the upper atmosphere would cause a column of atmosphere to be lofted to extreme heights increasing the density at altitudes up to several hundreds of Km by orders of magnitude in an area several hundred km in diameter beneath the burst.
So, several 1 Mt bursts at say 200 Km above the equator would do the trick for equatorial orbits.
Perhaps a better way: The HARP facility is used to mimic effects of high atmos nuke bursts and aurora phenomena by depositing rf energy in the atmosphere. Could ti be used to locally heat the atmosphere to cause atmospheric heave to accomplish de-orbiting at any orbital inclination?
Use massive nuclear explosions in high orbit to sweep all the junk into piles for more manageable deorbiting. And don’t tell me it isn’t practical or physically possible or it will damage all our satellites because I really really really want giant explosions in space.
Alternatively, one could use a sub-orbital rcoket to inject a cloud of something like Tungsten Fluoride gas also in an “almost full orbit” to cause de-orbit of very small objects. Small objects have high ratio of surface area to mass so are easier de-orbited this way.
My favorite scheme is to use lunar dust. We electrically charge lunar dust and use This dust would be fired toward earth using electrostatic fields where it would do the same thing as a dense atmosphere, momentum exchange and help de-orbit stuff. Some of the dust would enter the atmosphere (fantastic light show) and rest would exit the earth-moon system due to its velocity.
“Homer Hickam later wrote his own biography, “Rocket Boys”, about his experience growing up in Coalwood, Virginia,…”
That should be WEST VIRGINIA. (Let’s not start a fight.)
Including de-orbiting useful satellites still in service?
Marvellous, dahling, just marvellous …
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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? Because they’d be in different orbits if they weren’t? Presumably I’m wrong, but I’d like to know why I am.
Each kilo in Low Earth Orbit cost 10 to 11 thousand dollars to get it there. All that lovely mass in orbit and we can’t find a way to use it?
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
The (ahem) H. A. A. R. P. facility steerable ‘planar’ (RF active elements/individual antennas situated in 12 rows x 15 columns exist on a ‘plane’ or flat area) array has limited ability to phase-steer it’s beam, making this impractical exc. for the range it is capable of ‘seeing’ (being steered) overhead (IOW, it is not effective from horizon to horizon) from its location at about 62.4 degrees North latitude.
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Seems an awful waste not to find a space utilization for the debris.
We spent a lot of energy to get it up the gravity well, a tar baby type collector might be more practical than directing these treasures back into the atmosphere.
What about remote control vehicles to clump the pieces at specific orbits?
An extension of the drone technology seems possible.
Military training op?
Or new life for the space station?
” 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).”
The wait for the next solar “max” worthy of the name maybe rather longer than expected by the author. 😉
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.
More like 10,000 tons.
The Columbia shuttle had a mass on re-entry of about 100 tons and even massive parts like the engines didn’t reach the ground intact.
‘Intact” do you men in working order? 🙂
http://en.wikipedia.org/wiki/Space_Shuttle_Columbia_disaster :
“More than 2,000 debris fields were found in sparsely populated areas from Nacogdoches in East Texas, where a large amount of debris fell, to western Louisiana and the southwestern counties of Arkansas. Along with pieces of the shuttle and bits of equipment, searchers also found human body parts, including arms, feet, a torso, and a heart.[25]
In the months after the disaster, the largest-ever organized ground search took place.[26] NASA issued warnings to the public that any debris could contain hazardous chemicals, that it should be left untouched, its location reported to local emergency services or government authorities, and that anyone in unauthorized possession of debris would be prosecuted. “
John Robertson, re tar babies. How about a really big sheet of aerogel?
I’m against massive nuclear explosions in the atmosphere, the resulting EMP would cause significantly more damage here on the surface than it would clean up in space.
john robertson says:
March 26, 2013 at 11:37 am
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If we ever get to the stage where we can build a space elevator, it will require a counter-balance in geo-stationary orbit. Then it will be useful to have all that stuff up there already.
Bloke down the pub says:
March 26, 2013 at 12:07 pm
If we ever get to the stage where we can build a space elevator, it will require a counter-balance in geo-stationary orbit. Then it will be useful to have all that stuff up there already.
Bloke,
That is a valid insight. The cost to launch all of that now obsolescent hardware probably averaged $10,000/lb delivered to orbit or more (that’s an amount used as a rough rule of thumb for many launch systems in the 1980 – 2000 time frame). We have a sizable investment in orbital mass already. Why repeat it at needless cost…..
MtK
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?
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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.