New Scientist – Planetary Resources would like to put up at least 10 or 15 asteroid spotting space telescopes into orbit in the next five years, some of them on Virgin Galactic rockets. The Planetary Resources telescopes will be a lot less capable than Hubble, which is a billion dollar space vehicle the size of a school bus.
Our telescopes – which we call the Arkyd 100 spacecraft – are cubes half-a-metre on a side and will cost around $1 million each, though the first one, of course, will cost much more. But when they are developed to a high level of performance, we want to print them en masse on an assembly line. They will have sub-arc-second resolution, which is just a mind-blowing imaging capability.
The smaller we can make them the lower they cost to launch. Making them the size of a mini fridge, with 22-centimetre-diameter optics, hits the sweet spot between capability and launch cost.
Question – How can you tell if an asteroid might have platinum, gold or water deposits?
We’ll characterise them by studying their albedo – the amount of light that comes from them – and then with the appropriate instruments we can start to classify them, as to what type of asteroid they are, whether they are stony, metallic or carbonaceous. We’re starting with optical analyses though we could use swarms of Arkyd 100s with spectroscopic, infrared or ultraviolet sensors, too, if needed.
Question – Once you spot a likely asteroid, what then?
We’ll send other spacecraft out to intercept and study them. They will be rocket-assisted versions of the telescope – the Arkyd 200 for nearer Earth space, and the Arkyd 300 which is the same except that it will have a deep space communications capability. We’ll make sure we understand every cubic inch of that asteroid. We’ll find out where it is, what its inertia is, what its spin rate is, whether it has been burned, impacted, or is carbonaceous or metallic. We’ll know that asteroid inside and out before we go there and mine it.
Question – Will you be able to tell, remotely, if a space rock has lucrative platinum deposits, say?
Probably not. But we would be able to tell metals from water or silicates. There’s an asteroid out in the main belt right now called 24 Themis, and we’ve been able to sense water ice on its surface from way back here on Earth. Identifying metals will require spectrometry and direct analysis of the materials returned. The Arkyd 300 will get right up to the asteroid, land on it and take samples – like NASA’s NEAR and Japan’s Hayabusa missions did – then return pictures, data and grain samples back to Earth for analysis.
The data the 300-series gathers will allow us to design the mining spacecraft. There are many, many different options for that. They could vary from very small spacecraft that swarm and cooperate on a bunch of tasks, to very large spacecraft that look seriously industrial. Before we can begin the detailed design of a mining spacecraft, we need to actually go there, explore the asteroid and learn where the specific opportunities are.
Moving Asteroids closer to Earth
One of the ways that we could do that is simply to turn the water on an asteroid into rocket fuel and burn it in a thruster that nudges its trajectory. Split water into hydrogen and oxygen, and you get the same fuels that launch space shuttles. Some asteroids are 20 per cent water, and that amount would let you move the thing anywhere in the solar system.
Another way is to set up a catapult on the asteroid itself and use the thermal energy of the sun to wind up the catapult. Then you throw stuff off in the opposite direction you want the asteroid to go. Conservation of momentum will eventually move the thing forward – like standing on a skateboard and shooting a gun.