15 February 2011
Publications - Other (Bad)
What Is (And Isn't) Happening with Space Junk
SFJ corrects an article in The Independent
by G B Leatherwood
There are hundreds of operational satellites in orbit above us…as well as thousands of decommissioned satellites and their detritus, known as space junk. To date, 19,000 of these not-so-heavenly bodies are currently being tracked, but it is estimated that over 600,000 pieces over 1-centimeter wide exist.

With an increasing number of countries and companies lofting vehicles, satellites, and habitations into space, space junk is becoming a major concern; even a tiny piece of seemingly harmless debris--such as a flake of paint--can wreck havoc. For example, in 2006 a small fragment of a circuit board hit the Space Shuttle Atlantis and punctured a hole through the radiator panels in the cargo bay.

In the article “’Fishing net’ to collect space debris”, published 10 February 2011, reporters Danielle Demetriou and Peter Hutchison of the UK newspaper The Telegraph described a joint venture between the Japan Aerospace and Exploration Agency (JAXA) and manufacturer Nitto Seimo Co. to deploy a kilometer-wide net to capture and remove space junk before it could puncture space habitats and cause damage to working satellites.

Unfortunately, the facts were lost in translation.

The Telegraph reported that this “fishing net” would be composed of ultra-strong, ultra-light strands woven together using the techniques first developed by Nitto Seimo in 1925 for knotless fishing nets. When fully deployed, the net would theoretically scoop up fragments of debris, such as fallen bolts from rockets and satellites.

Intrigued by this news, Space Future Journal spoke with Eisuke Aizawa, of the JAXA Public Affairs office, who corrected the errors for us.

“There may be some translation errors or misunderstandings. Let me explain the actual situation.

“Researchers have been developing a tether system with Nitto-Seimo technology, but it will not be used for capturing debris like fish net. The idea is to attach an electrodynamic tether to the debris object by a robot arm or something. The tether will collect electrons from the ambient plasma to flow an electric current through the tether and then generate Lorentz force via interaction between the current and the geomagnetic field. The object velocity will be reduced continuously by this method, which will lower the object altitude and lead to a shorter lifetime.

“By the way, the concept is still in the research level, and we have no actual plan to realize the idea at this time.”

In other words, even if JAXA and Nitto Seimo are considering the feasibility of a physical net to capture space junk, other ideas are being examined. But to date none have reached the demonstration stage because of the expense and feasibility of the project.

This is disappointing news, considering the urgency of the problem. Just one paint chip scattered at the wrong moment can lead to dire consequences for existing satellites, the International Space Station ( ISS), the nascent space tourism industry, and to human spaceflight in general.

Frighteningly, in 1978 NASA scientists Donald J. Kessler and Burton G. Cour-Palais predicted, based on the data available at the time, that the existing debris would impact on itself, generating even more debris, which would develop an alarming cascade effect.

Fortunately, his predictions, known as the “Kessler Syndrome,” have generated new policies governing the rights and responsibilities of governments and private owners to build safeguards into their vehicles that would keep their orbits debris-free.

Other safeguards have been developed, such as the “Whipple Shield” or MicroMeteOroid Deflector (MMOD), a thin membrane on the outside of spacecraft such as the ISS, which intercepts tiny fragments, including micrometeorites, and causes them to dissipate before reaching the skin of the spacecraft.

One thing is certain, however: space junk does exist, and it is a real problem that will not go away. It's even guaranteed to worsen in time. The Kessler Syndrome suggests that the cascade effect will occur even if no further launches take place. It is imperative that solutions be found, financed, and implemented sooner, not later.
Share |
G B Leatherwood 15 February 2011
Please send comments, critiques and queries to feedback@spacefuture.com.
All material copyright Space Future Consulting except as noted.