Space calamity boffins at Airbus and the European Space Agency (ESA) have come up with a new take on that old "massive, rogue impactor striking the Earth and wiping out all life on the planet" chestnut.
Rather than sending teams of astronauts, cosmonauts, and unlikely groups of oil workers to destroy the incoming rock with nuclear weapons, the European rocket scientists reckon they could knock it off course by pelting it with hijacked communications satellites.
The Airbus/ESA whitecoats felt that if humanity detected a possible asteroid impactor early enough to give us three years' warning, given the time it would take for any solution to get to the point of impact, it still might not give us enough time to create, build, and launch a suitable defence.
This means that if we were going to try and deflect the asteroid (a proposal which is probably easier and more predictable in its results than trying to blow it up, as depicted in the movies Armageddon and Deep Impact), we would ideally need something that is big, heavy, steerable, and numerous.
Fortunately for us, we already have an ample supply of such resources. Modern comms satellites are chunky beasts that can weigh between four and six tonnes. They normally live on geostationary orbits around the Earth's equator, in a band 22,236 miles (35,786km) from the planet's surface. They also have engines to keep them on station and aligned with the relevant transmitters on Earth.
And there are also a lot of them, with 15 such satellites being ordered in 2019 alone. This means that during any given year, there will normally be more than a dozen comms satellites at various stages of construction.
The Airbus/ESA plan – known as the Fast Kinetic impactor Deflection mission, or FastKD – is to "hijack" the production of those satellites at whatever stage they are at, remove the communications equipment, install a new kinetic deflector (KD) pack incorporating more engines and control gear, load it on a rocket, and launch it at our potential incoming doom.
Although the six-tonne interceptors would be tiny in comparison to the 1000-ft (304.8m) diameter asteroid projected in the FastKD study*, if the world was able to get them launched quickly enough to hit the rock far enough away, the tiny changes in trajectory caused would hopefully be enough to nudge it away from its collision course.
The speed of the project is therefore key. Given a time of three years between detection and projected Earth impact, the FastKD timeline allows only six months for political decision-making and the commandeering, adaptation and testing of under-construction satellites. It also allows only a one-month window to launch all of the necessary vehicles, in order to have them hit the incoming asteroid in quick succession for maximum effect.
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Despite the difficult timeframe, Albert Falke, the project lead at Airbus, thinks it is possible.
"These telecommunication platforms, in addition to being large and heavy, are also built with quite a high frequency," he said in an interview with Space.com. "That means we can expect them to be available readily in the integration facilities. That's something we can take for granted."
With a prospective extinction-level impact on the cards, you'd hope so. Having the birds ready to be hijacked is not the only possible problem, though.
"The bottleneck will be the rockets," Falke added. "[But] we think we could expect about 10 to 15 launches available within one month around the entire globe." This sounds optimistic, but it's that or we all die so you'd hope everyone would be on board.
After launch, the kinetic deflectors would cruise for 6-18 months before hopefully hitting their target. Our continued survival as a species would at that point depend on the boffins getting their maths right.
They will be helped in this by the NASA DART (Double Asteroid Redirection Test) project, which is on track to intercept an asteroid called Didymos in September next year. NASA then intends to crash an 600kg impactor into Didymos's 160m (520ft) diameter moonlet at a speed of 6.6km per second (4.1 miles per second) just to see what happens.
Hopefully the DART project will allow impact-dodging scientists of all kinds to perfect their extinction-avoidance techniques in a way that will not make Liv Tyler cry, a criteria which everyone agrees exceeds all others in importance. ®
*Although FastKD does not give a mass for the asteroid, the similarly sized 99942 Apophis – which is expected to come within 19,800 miles (31,900km) of Earth in 2029 – is estimated to weigh around 61 million tonnes. We at The Register suspect an impact by such an object would make Liv Tyler very, very unhappy indeed, so is to be avoided at all costs.