Despite its reputation for wackiness and love of robots, building terrifying running robots and proto-Terminators is something Japan generally leaves to America. No, Japan is too busy figuring out how to mug you in space. And they’ve now got a working prototype of a space cannon!
Building a ballistic weapon in space is harder than it looks. Despite what you might think, a gun would work in space; lack of oxygen isn’t the issue. Temperature, however, is. It’s pretty hard to make something blow up when it’s at absolute zero; that’s why most space weaponry that’s actually been proposed and built tends towards lasers or railguns, which are less sensitive to temperature and also more appealing to the eight-year-old in us all.
Fortunately, Japan doesn’t want to blast your house from orbit. They want to blow a big-ass hole in a space rock.
The space cannon is to be mounted on the Hayabusa-2 vehicle, which will carry it to the asteroid, which orbits between Earth and Mars. This is essentially a kinetic impact weapon that relies on an explosive charge to launch a 4lb slug into the surface. The spacecraft will release the weapon, allowing it to float downward while it takes cover on the opposite side of 1999JU3.
Here’s a video demonstrating how it works. You… might want to mute this one.
The idea is that 1999JU3 is a rock from the very beginning of the universe, and blowing a hole in it will allow JAXA (yes, Japan’s space agency is called JAXA) to get a better idea of what it’s made of, thus possibly opening doors to a better understanding of the beginning of the universe. Owning a space cannon, strapping it to a satellite, and blowing stuff up with it is just a bonus.
Alas, this won’t be happening soon; the actual asteroid blasting won’t happen until 2018 and we won’t get data until 2020. But who cares? We want to see how DARPA one-ups this. We’re assuming it will be the same thing, but with more explosives and set off by a laser.