Space debris swarming around our planet reveals man-made dangers of space travel

Wednesday, October 29, 2014, 2:36 PM - There's already cosmic radiation to worry about, plus things like micrometeorites and technical failures, but the above video, released by NASA this week, provides an updated look at the truly incredible amount of junk floating around our planet, highlighting just how dangerous we've made it up in orbit.

Orbital Sciences' rocket failure on Tuesday night certainly gives us a dramatic reminder of the dangers involved with just getting a rocket into orbit. However, once a rocket makes it up there, it - and most especially its payload - face further risk from the virtual swarm of space junk whizzing around the Earth. This junk ranges from the biggest - rocket boosters, fuel tanks and defunct satellites - to the smallest - nuts, bolts and tiny fragments - all resulting from either standard operating procedures during orbital insertion (like rocket stage separations), or even collisions between objects. As the video shows, much of the stuff that's located further out - either mixed into the ring of geostationary satellites (roughly 35,000 km from Earth's surface) or scattered out into the large sphere that surrounds the planet - is pretty spaced out and slow-moving. However, as the video dives through that into low-Earth orbit, it's actually difficult to see the surface through the whizzing, whirling, kilometres-thick layer of junk, that's travelling at an average speed of around 30,000 km/h!

NASA's Orbital Debris Program Office, located at Johnson Space Center in Houston, TX, is one of several efforts (along with those of the European Space Agency, schools like the University of Maryland, and others) to track the debris left in orbit by the thousands of rocket launches we've had since the 1950s.

The information gathered by these programs is used to keep the functional satellites that are in orbit, as well as the International Space Station, safe from collisions.

Credit: Rlandmann via Wikimedia Commons.

One month ago, on September 28, the tracking information on one particular piece of debris caused some concern about a potential collision with the polar-orbiting atmosphere/ocean monitoring NASA-NOAA Suomi NPP satellite. Although there was some uncertainty about the size of the object (anywhere from 10 cm to 1 m wide), the projected head-on collision with Suomi NPP would take place at a relative speed of around 56,000 km/h. At that speed, even a 10 cm object would completely destroy the 2-ton satellite. It was an easy maneuver to have Suomi NPP sidestep the debris, but these kinds of maneuvers are becoming more common.

Just a few days ago, the International Space Station had to perform an adjustment to their orbit to avoid what could be one of the most famous pieces of space debris currently in existence.

Back in 2009, two satellites - the defunct Russian Kosmos-2251 military communications satellite, launched in 1993, and Iridium 33, part of Iridium Communications Inc's communication satellite constellation - collided over northern Siberia, on nearly perpendicular trajectories. The impact between the two tore both satellites to pieces, and spread those pieces into debris fields along their original orbits. What the International Space Station had to dodge on Monday, October 27, was a chunk of the Kosmos satellite, which was projected to pass within around 300 metres of the station. That may seem like a fairly wide berth to begin with, but given the potential uncertainties in the orbit, plus the possibility of a wider 'cloud' of smaller (and thus much more difficult to detect) debris that might be surrounding the larger piece, the decision was made to move the station further away to avoid trouble.

Although there's a fairly constant 'trade' between Earth and space, with more launches going up, and space debris falling down to burn up in the atmosphere, officials recognize the growing problem of this orbiting junkyard. Perhaps the biggest problem is something known as the Kessler Syndrome. If you've seen the 2013 movie Gravity, or you at least know the plot, that is an excellent (if accelerated) example of this issue. The essence of NASA scientist Donald Kessler's point is that, as more hardware ends up in space, it increases the chance of a collision between those objects. Each collision then increases the chance that there will be more collisions, and this increases at a fairly alarming rate after that until we reach a point where sending anything up into orbit is essentially consigning it to destruction. The Kosmos-Iridium collision, and the destruction of a Chinese weather satellite by a military test two years prior to that, already have the 'ball rolling' for the Kessler Syndrome. It won't advance to be as bad as it was in Gravity just yet, but the idea is that this is inevitable.

There are plenty of plans in the works to reduce the amount of junk floating around up there, mostly dealing with sending up satellites to gather up the junk, whether by net, harpoon or some other 'traditional' method, or even to use gravity itself to deorbit this stuff. SpaceX is taking a rather proactive lead on the issue too, by developing rocket stages that can actually return to Earth after launch, thus keeping them from joining the swarm in space.

If you'd like to keep track of this space junk, there are websites such as SatView.org, which monitor satellite orbits and project the re-entry times of different objects. There are also interactive tools, like Orbital Objects, that provide updated views of where all this junk is around the planet.