FEAR #1: Space Debris

The internet is a smorgasbord of fearmongering. Climate change, Ebola, gluten intolerance, skipping leg day… what should we really be afraid of? And to what extent? In the first edition of FEAR we tackle an issue high above our heads, space debris.

The importance of the space industry is often understated and in recent decades the economic and emotional frenzy of the Apollo program has given way to a more intuitive, though not necessarily correct, sense that everyday earthly issues are far more pressing. With this in mind it is important to restate the just how vital it is for humanity to maintain a strong space industry.

In the long term it is expected that space technology will allow humanity to permanently cut itself loose from the gravitational umbilical cord that tethers it to a doomed Mother Earth, a subject that is discussed brilliantly here. Admittedly the short term is less exciting, but the use of satellites is essential for many things we take for granted including weather prediction, communications and navigation, as well as research into climate change and famine.

Space debris, which is largely comprised of satellites and rocket stages that have ceased to be operational (although humanity has been creative when it comes to making space debris, see the table), poses an existential threat to all working satellites. The collapse of space infrastructure may leave the next generation pining for widespread mobile data coverage and satnav in the same way that I long for the transcendental excitement provided by the Apollo missions or Concorde.

Method Who When Example
Anti-Satellite Weapons USA, China and the USSR USA and USSR during the Cold War, also China in 2007 and USA in 2008 In 2007 China blasted one of its satellites into over 3,000 pieces of trackable debris (>10 cm) and probably a shitload more of the smaller stuff that we can’t detect (until it destroys something useful).
Not venting Fuel Tanks All spacefaring nations All the time until recently In 2012 at least 1,000 trackable fragments were produced when fuel in the upper stage of a Russian Briz-M rocket decided to explode. Thanks Russia.
The West Ford Projects USA 1960s Hundreds of millions of tiny (1.78 cm) copper needles were released into orbit in an attempt to bounce radio signals off them. Some of the needles were deployed incorrectly and remained in clumps that still orbit to this day.
Clumsiness Astronaut and Cosmonauts More often than you’d like to think Many items were lost on spacewalks or jettisoned during the lifetimes of the International Space Station (ISS) or Mir, the Russian Space Station. Like this toolbox.

Proof of the damage space debris is capable of. Left: 1.2 cm ball bearing fired at 6.8 km/s (via ESA). Right: Damage to a window on the Challenger spacecraft, caused by a 0.2 mm fleck of paint (via NASA).

What endows space debris with its destructive power is its tendency to travel at incredibly high speeds, up to around 7 km/s (~17,500 mph). At these speeds a collision with anything larger than 10 cm will rip an orbiting satellite to pieces and even a 1 cm piece of debris can hit with an energy equivalent to an exploding hand grenade. Collisions inevitably create more debris and increase the likelihood of further collisions in a domino effect that eventually becomes self-sustaining. This is known as Kessler syndrome and if it occurs everything in orbit will be ground into a fine dust and the orbits surrounding the Earth will become entirely unusable for spacecraft for decades.

space debris graph

Distribution of space debris as of 2007. From G. Forden, Massachusetts Institute of Technology. For an excellent interactive graphic click here.

Now, if you’re optimistic that this scenario is unlikely because all that debris is tiny in the vast infinity of space… allow me to rein you in with some hard facts.

Firstly, space, at least the regions of it where satellites and debris orbit, is not that big. Most satellites are found in two regions, Low Earth Orbit (LEO) which extends from 160-2000 km above the Earth’s surface and Geostationary Orbit (GEO) at 35,786 km above the Earth. The evidence suggests that Kessler syndrome is most likely to begin in LEO, more specifically in crowded orbits over the poles at altitudes of 600-1200 km.

iridium and cosmos collision

Two satellites, Iridium 33 (active, 560 kg) and Cosmos 2251 (de-activated, 950 kg), collided in 2009. The collision created over 1,600 trackable debris items in regions frequented by telecommunications satellites (via NASA).

Secondly, humanity has left a lot of debris up there. The US Air Force track >22,000 objects larger than 10 cm in LEO using radar, while computer simulations estimate that there are 150,000-700,000 objects >1 cm and hundreds of millions >1 mm.

Some of this debris has already begun to collide, see image on the right. Estimates from 2010 suggested an average collision rate of once every five years. Since then, computer simulations have suggested that even if new launches were to cease, the multiplication of debris will be self-sustaining.

Obviously a moratorium on launches is ridiculous and impractical. In fact, a new space race is underway, driven by a mixture of emerging spacefaring nations and rapid commercialisation of space. A result of this is the shift towards the use of CubeSats. These are cheap satellites that companies plan to use in large constellations. The idea is well intentioned as CubeSats offer the potential to make space exploration far less exclusive, however, you get what you pay for and many of these CubeSats lack manoeuvrability, making them highly likely to collide and do more harm than good.

Essentially, Kessler syndrome is already upon us (can’t stress enough just how bad that is) and as time passes space will become an increasing harsh environment to operate in. Ignoring the problem will render space too dangerous for future use and send many of the systems that modern society is dependent on into terminal decline. Now that I’ve got you worried I’ll let you know what our best and brightest are doing to save us all.


GIF showing a net capture mechanism for use in the e.Deorbit mission (via ESA).

Leading the charge is ESA, which has begun working on a mission called e.Deorbit (due for launch in 2021) to bring a defunct satellite out of polar LEO. Several mechanisms for removal have been mooted, including the use of a net as shown on the right.  Where possible, ESA has also begun to remove its satellites from crowded orbits at the end of missions (e.g. ERS-2). Further to this, the risk of satellites exploding is being managed by draining fuel, venting tanks and switching off batteries.

Brief aside: As a UK citizen I’m shocked at how little we fund ESA. The UK contributes less than half of the amount France and Germany do and Italy push us into 4th place! No offence Italians, but we should be doing better than you, so some offence I suppose.

The US Air Force has also invested in a new generation of space surveillance called Space Fence, which will be capable of tracking 200,000 objects that are smaller than those currently tracked. This infographic by Lockheed Martin describes how Space Fence will protect US “warfighters”, in case we were wondering where their priorities lie. Contracts have been negotiated to allow other bodies access to the data, but the extent of this access has not been made public, probably because the US has a habit of being precious about its military operations. This may be the reason why a group of European nations are planning to develop detection infrastructure independent of the USA.

To summarise humanity’s plan, the Europeans plan to limit the mess they make and remove a dead satellite (that’s “a dead satellite”, as in, just the one and it’s going to cost millions) and the US is going to have a front seat if they fuck it all up. In order to stop the debris collisions becoming self-sustaining we need to remove 5-10 pieces per year and this is a mission to remove one piece in six years’ time. It leaves me thinking that this just isn’t good enough and that more would be achieved with international collaboration.

Ah international collaboration, the dreamer’s solution to all world issues. But wait, space is one of the few areas that buck the trend of simmering contempt between nations, the International Space Station stands alongside the Montreal Protocol on CFCs as one of the few real international successes. Unfortunately, this bonhomie doesn’t extend to space law so the UN hasn’t really gone near it since the 1970s. This leaves us with international agreements whose application to space debris is vague and insufficient for the contemporary space industry.

In conclusion, we appear to have a “tragedy of the commons” situation where our long term losses will outstrip our short term gains. Current efforts to mitigate space debris are insufficient and the required funding to tackle the problem quickly and effectively is not forthcoming. Further to this, an international agreement is unlikely and failing that we’re looking for someone/something to act unilaterally and at considerable expense to save us from what will be a social disaster. Yeah I’m worried about this.




One thought on “FEAR #1: Space Debris

  1. Pingback: FEAR #5: The Hunt for E.T. | Current Offence

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