Japanese scientists successfully tested a ‘space cannon’ this week

Not content with merely breaking the bonds of gravity and touching the face of God, now we want to fire plastic explosive into it.

By Ian Steadman

A reminder there are some damned exciting space plans being worked on right now – in Japan, scientists report that a “space cannon” they have been building is armed and fully operational, and has been tested successfully (albeit not actually yet in space).

Hayabusa-2, designed and built by the Japan Aerospace Exploration Agency (JAXA for short) will be launched into space next year, and head off to intercept the orbit of an asteroid called 1999JU3. It’s the successor probe to Hayabusa-1, which landed on the asteroid Itokawa in 2005, collected some samples, and returned home. It was the first such sample-and-return mission, one which Hayabusa-2 will build on.

1999JU3 is roughly a kilometre in diameter, and is an Apollo asteroid. That’s a class of asteroid that orbits the Sun within the orbit of Mars, in between the innermost three plants of Mercury, Venus and Earth. They occasionally cross into our orbit, making them a threat – that’s what the Chelyabinsk meteor was – but 1999JU3 isn’t. It is an interesting one, though, because it’s assumed to be made up of material similar to those found on the early Earth, and thus carry some of the organic compounds that we assume, on our planet, become life.

But you’re here for the space cannon, right? Here’s how it’s going to work.

After arriving at the asteroid sometime in 2018, and after taking 18 months’ worth of readings, Hayabusa-2 will deploy its cannon on one side of the asteroid (plus a camera so it can watch) before heading over to the opposite side. That way, nothing from the explosion should damage it.

Then, the space cannon will drift in. As it gets close to the surface it’ll detonate, firing a bullet containing 4.5kg of plastic explosive into the asteroid’s surface, blowing a crater into the asteroid’s side. Hayabusa-2 will emerge from hiding on the far side, swoop down to the exposed wound, and scoop up some samples. Then it’ll fly home, returning by 2020.

Alas, it is not quite as cool as Nasa’s awesome plan to capture an asteroid and pull it into orbit around the Moon. If we did that, we could send astronauts to it as practice for tricky things like landing on Mars or even distant moons. We might be watching footage of humans setting foot on another tiny alien world as soon as 2021, as long as funding can be found.