26Mar2016

5 Problems with Space Junk

Space junk: a conceptual artwork representing defunct satellites, failed missions, and shrapnel orbiting a few hundred miles above Earth. Photo: Science Photo Library

In the past several decades, advances in space infrastructure have fueled mankind’s efforts to understand the universe. However, that hunger has produced its own set of problems.

Space junk — defunct satellites, spent rockets and debris — is clogging up the orbital space around Earth, posing risks to current space infrastructure and limiting the launch of future projects. Here are five problems connected to space junk:

Limiting Exploration

Presently, organizations like the US Space Surveillance Network are monitoring the paths of more than 22,000 pieces of space junk orbiting up to 17,500 mph. That’s a lot of junk traveling at fast speeds.

All of this junk takes up valuable orbital space and trajectories. This limits the ability of agencies like NASA to launch technology that could lead to new discoveries. In addition, any satellites launched risk becoming part of the problem.

Kessler Syndrome

The fear behind the growing space junk problem is the development of a Kessler Syndrome-type scenario. This concept may be familiar to fans of the film “Gravity” or Neal Stevenson’s novel “Seveneves.”

In layman’s terms, Kessler Syndrome is caused by colliding pieces of space junk. The high-speed collisions cause the junk to fragment into smaller pieces. These fragments then cause more collisions, forming a perpetual cycle. The European Space Agency (ESA) has developed an excellent video illustrating this phenomenon, and how the debris spreads over time.

The presence of space junk is already a risk to satellites and the International Space Station. As collisions and fragmentation escalate, the risk of damage to vital satellites increases tremendously.

Red Conjunction

The potential human risk of space junk is summed up in the term “red conjunction.” This is when a piece of debris’ orbit is close enough to the ISS to warrant avoidance maneuvers. Because the ISS is pressurized, collision with even a small piece of debris could be fatal to the entire crew.

Getty Images A computer-generated image of objects in low earth orbit.

Notably, on July 17, 2015, debris from a Russian weather satellite wasn’t detected in time for the ISS to make maneuvers. This forced the crew to take shelter in a docked Soyuz vehicle to wait out the pass. Fortunately, the ISS wasn’t hit. But if one of the station’s modules had been, depressurization — or worse — could have occurred.

Growing Threats

Besides the ISS, the risk to other satellites needs to be considered. Most of the world’s communications and weather satellites are in co-orbital geosynchronous orbits, which means that two or more objects almost share the same orbit.

The cost to fix and re-launch a downed satellite is enormous, not to mention the damage to communications and military systems the crash would cause. There are propositions for methods of reducing space junk, but each has its own set of problems.

Space Junk Solutions

The space junk problem is being tackled by a number of agencies, from the U.S. government and the ESA to commercial startups like Planet Labs. Each solution has its merits, but is often held back due to funding, technological and legal issues.

Over the last decade, the U.S. government has increased its investments in space junk detection and tracking technology. The U.S. Air Force has systems that track the orbits of about 21,000 pieces of debris larger than 10cm.  The government has granted one billion dollars to build the Space Fence radar system to monitor as many as 200,000 pieces of small debris. These tracking systems will help provide some notice of collisions.

The San Francisco startup Planet Labs is proposing “cubesats” to make efficient use of what orbital space is left. These mini satellites are smaller than a briefcase and can take high-res pictures of the Earth. While the “cubesat” technology will help agencies develop smaller satellites, it does little to solve the problem of the junk already in space.

It maybe just a still from a movie but even a tiny piece of debris can inflict considerable damage, or even destroy an orbiting operational spacecraft.

The ESA has proposed a project called “e.Deorbit” to safely remove one of its satellites from orbit. However, it is held back by numbers, technological, and financial hurdles. In 2016, the project will go before the ESA Ministerial Council meeting for discussion.

To Dennis Wingo, CEO of Skycorp Inc., the key to solving the space junk problem lies in finding an adequate energy source. He proposes to use electrodynamic tethers to slow the debris and pull it into a low enough orbit for it to burn up in the atmosphere. However, this technology is still in its infancy.

While humanity’s venture into space is an important milestone, our apparent inability to manage space junk proves that we still have many hurdles to overcome as we explore our universe.

Megan Ray Nichols loves discussing the latest scientific discoveries with others on her blog Schooled By Science. When she isn’t writing, Megan is discovering the beauty in the world around her with her new telescope. You can follow Megan on Twitter @nicholsrmegan.

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