Imagine, for a moment, what an incomprehensible event it would be if you were walking down your street, minding your own business, and you were randomly struck by a bullet fired during World War II, half a world away and many decades ago. Somehow, that bullet has been flying around all this time until it just happened to find you. What would you do? Maybe the person who fired it has since died of old age. Maybe the country they fought for no longer exists. On whom does the responsibility fall? Not that it makes much difference to you in the moment, does it? Ouch!
Fun with hypotheticals aside, we know such a thing couldn’t happen on Earth because of gravity and atmospheric drag. Space debris is different. Something very much like this can happen in space because the vast speed at which orbiting objects travel is sufficient to beat gravity, and the length of time these objects can stay in space is due to the lack of atmospheric drag. The space debris problem will persist for decades to come, and the questions of responsibility are much the same.
The statistics on space debris are worrisome. According to the recently updated ESA space debris by the numbers page, there are now an estimated 34,000 pieces of space debris larger than 10cm in orbit around Earth (these are the ones that can be tracked), with another 900,000 objects big enough (>1cm) to do catastrophic damage to any spacecraft with which they happen to run cross paths.
Most of these are in Low Earth Orbit (LEO), since that’s where the majority of humankind’s activity in space has been. Of course, if you look at the absolute density of debris, the numbers might seem very low. The roughly 8400 tons of artificial objects in space are spread out over an area larger than the size of Earth’s surface, and even a back of the envelope calculation will tell you this works out to about 14 grams per square kilometre. Then consider that this is spread over a volume hundreds of kilometres in altitude, and you realise the standard graphic of space debris showing the space around Earth thick with particles is merely an artistic representation.
The nature of the problem becomes more clear when you contemplate the phrase “hypervelocity impact”, and see images like this solid block of aluminium after impact by a small (~1cm) metal projectile travelling at approximately 8km/s:
Several innovative shielding approaches are being developed at NASA and elsewhere in an attempt to protect human-rated spacecraft from the millions of debris objects of this size, but clearly, prevention is better than a cure. The problem won’t go away until we make it go away.
If anything, the problem will get worse before it gets better: Another 10,000 or so satellites are planned to be launched in the next decade, many of which will be in the orbits where debris populations are highest. This is in addition to the 1800 or so currently functional satellites. The odds of further random collisions between satellites and debris (or indeed between debris and other debris objects) creating further clouds of space debris, is not insignificant, and it’s because of this fact that a sizeable space debris clean-up industry is currently in the gestational stages. We now expect this industry to be in the billion $/year range by 2030, given that the total space industry is projected to reach a trillion-plus $/year at or soon after this date.
Exodus Space Systems intends to be a leader in the space debris clean-up industry, and we think Western Australia’s growing prowess for space situational awareness (SSA) makes it an ideal location from which to operate. We’ve been hard at work developing a novel technology which will cost-effectively solve this problem, a complete financial model showing who will pay for it and why, as well as a pack for investors describing all the details.
Here’s to some exciting meetings in the next few weeks!