Taking Out the Space Trash

A growing cloud of trash threatens space tourism and has experts scrambling to clear the mess

By Ker Than Posted 06.27.2008 at 1:58 pm 9 Comments

Trash Collectors Robots could gain momentum to change orbit by swinging weighted tethers like a discus thrower does. This would move them to large pieces of old debris, to which they would attach Terminator Tethers. John MacNeil

Along with satellites and space stations, Earth is surrounded by tens of millions of pieces of floating space debris. Like any landfill, the trash is diverse, ranging from dead satellites to castaway rocket parts to flecks of paint. On average, over the past 40 years, one piece of space junk has fallen to Earth every day.

Laser Brooms: Baseball-size pieces of debris are too small for tethers but large enough to pierce spacecraft. Hitting them with lasers would disrupt their orbit, causing them to fall and burn up. John MacNeil

Space agencies have managed to avoid major in-flight catastrophes with protective shielding and deft maneuvering of manned vehicles and satellites. But if we keep launching satellites and do nothing about the mess, the amount of unpredictable debris in orbit will make already-risky manned spaceflight more dangerous.

Scientists at NASA and private companies have devised several ways for clearing the sky. Although some methods are admittedly outlandish, says Nicholas Johnson, the chief scientist for orbital debris at NASA’s Johnson Space Center in Houston, Texas, a few are possible with today’s technology.
One early idea was to have robotic trash collectors shove large pieces of junk through the atmosphere so that they mostly burn up before hitting the ground. But the fuel costs for destroying a significant amount of debris with such craft has quashed this approach.

Space Flypaper: A half-mile-wide “Nerf ball” could intercept small debris, reducing their orbital energy so that they lose altitude quickly. Hang-ups include keeping the ball afloat and away from functional satellites. John MacNeil

A more feasible plan is to attach miles-long “electrodynamic tethers,” wound on a spool, to all new satellites. Once a satellite ends its mission, it would deploy the cable and Earth’s magnetic field would induce an electric current in it. This interaction imparts a force on the craft that pushes it through the atmosphere until most of it burns up harmlessly, says Rob Hoyt, the president and chief scientist of Tethers Unlimited, a company working to develop the technology.

Tether demonstrations have so far yielded limited success or failed outright, but despite the setbacks, Johnson and others are optimistic that the tech could be ready in a few years. Here, a look at how the tethers might make the sky safe for space travel.

Step 1 After a spacecraft completes its mission, a three-mile-long Terminator Tether that is attached to the satellite unravels from its spool.
Step 2 Interactions between the Earth’s magnetic field and the charged ionosphere create and drive an electrical current in the metal tether.
Step 3 The current generates a Lorentz force—a phenomenon that affects charged particles moving in magnetic fields—that opposes the spacecraft’s orbital motion.
Step 4 Over the next weeks or months, the Lorentz force pushes the craft to lower altitudes, until it mostly burns up in Earth’s atmosphere.

Previous Article: Big Baby

Next Article: Martian Soil Is Alkaline

9 Comments

Link to this comment

AmberFoxFour

06/29/08 at 10:50 am

You must admit, that is some pretty cool stuff!

JT
www.FireMe.To/udi

Link to this comment

uocotp

06/30/08 at 9:08 am

Thats a lot more technical than my idea of a giant space trashcan.

Link to this comment

gaetanomarano

07/01/08 at 7:07 am

CLEAN space from DANGEROUS debris and trash could be one of the BEST goals for a good COTS program...

unfortunately, the real (NASA funded) COTS are just a DUPLICATION of other (existing and future) ISS cargo and crew services, as explained in my "What's wrong in COTS" article:

http://www.ghostnasa.com/posts/020wrongcots.html

in this article, I also suggest of to do a better COTS program

Link to this comment

gaetanomarano

07/01/08 at 7:08 am

post edit:

in this article, I also suggest... HOW ...to do a better COTS program

Link to this comment

macro820

07/04/08 at 2:02 am

Why don't they work out disposal before deployment?

Link to this comment

ad_astra

from Geelong, Victoria

07/07/08 at 4:07 am

if someone was able to capture and recycle the junk, it would make feasibility less of a problem :P

Link to this comment

Moonfire

07/16/08 at 11:34 pm

Why not orbit magnetic wands that suck the debris out of orbit? Using large orbiting magnets makes more sense, and would cost far less!

Link to this comment

doughboyky6

07/21/08 at 7:53 pm

I think this technology is great but Im still amazed why this wasn't addressed earlier, if NASA wanted to continue to grow they should have made this a priority. They cant continually send up large satellites, space stations, etc. without cleaning this up!!!

Link to this comment

ldkinfo

04/15/09 at 10:37 am

Some Soviet satellites used nuclear fuel to provide power for their satellites. One in particular returned to Earth spreading radioactive debris across Canada.
A safer alternative might be to attach robot boosters to these and other satellites to boost them into deep space or the sun.
Some old satellites might be able to be used to act like Shephard moons to catch debris as they travel around the planet. Debris colliding from behind might cause too much damage, but if a satellite were to "catch up" with the debris, velocities might be low enough to allow the debris to imbed itself without causing serious damage.
Future specially designed "shephard satellites" could use large panels in place of solar arrays to capture debris. Starting in a high orbit, orbital decay could be used to reduce altitude while debris is being collected. Once fully loaded the satellite could then be sent into deep space.
L.David Korkia