In the Oscar-nominated Hollywood movie ‘Gravity’ the orbiting International Space Station (ISS) is smashed to smithereens by orbiting debris. While in 2012 the whole ISS was gently moved four times because of the dangers from orbiting debris, last year was calmer despite a growing threat from all-too-real debris.
NASA says that 2013 was a relatively quiet year, which is remarkable given that the ISDS has had to readjust its orbit on 16 separate occasions over the past 15 years. However, before the authorities and the astronauts relax too much the fact is that over the past few years the crew had to undertake an emergency transfer to the tethered Soyuz escape capsule on three occasions because the incoming debris warning alarms went off too late to move the complete Space Station.
NASA’s data, gathered from the USA’s Space Surveillance Network (SSN) of sensors, shows that the amount of debris has increased by 60 per cent since the first element of the ISS was launched in 1998. That the threat of damage is real is proved by the close monitoring by SSN of more than 800 items in close proximity to the ISS ranging from less than a kilogram up to more than 1000 kg in size. But the ISS says there are another 5000 objects which intersect the Space Station’s orbit, and that most of these 5000 objects have yet to be recorded into the SSN’s master catalogue.