Packed with toys to deploy on the asteroid (Image: JAXA)

We can’t get enough of space rocks. Just weeks after Rosetta’s comet landing, Japanese space agency JAXA today successfully launched Hayabusa 2 – an ambitious follow-up to its Hayabusa probe, which landed on an asteroid in 2005.

Hayabusa 2 will peck at the asteroid’s surface to take samples and place four devices on it – including Mascot, a lander based on Philae technology. More spectacularly, it will hurl a 2-kilogram explosive device called a small carry-on impactor at the asteroid to create an artificial crater. Ejected material and the rock layers exposed by the impact can then be analysed. Watch a test firing of the explosive here.

Hayabusa 2 launched from the Tanegashima Space Center in Japan on an H-IIA rocket and will arrive at asteroid 1993 JU3 in 2018. That rock has been chosen because its reflectivity suggests it contains much organic matter and water, hopefully revealing insights into the origins of water, and therefore life, in the solar system.


Little leaping landers

Unlike Rosetta, Hayabusa 2 will sample the surface itself, using a probe mechanism slung beneath the craft to catch surface dust. To aim for a good sampling spot, the spacecraft will drop a target marker on the asteroid’s surface – effectively a beanbag it can home in on. It will also send back to Earth a sample from the artificial crater it creates, and this should arrive in 2020.

Hayabusa 2 is carrying three tiny, hopping rovers that will land on the asteroid – they are upgraded versions of one lost in space on the original Hayabusa mission. Inside the rovers are weights called torquers, and swinging these is what enables them to hop around.

The Mascot lander has been designed by German aerospace lab DLR – where Philae was developed. A simple box-shaped lander with no legs, Mascot’s aim is to study the surface with four imaging and magnetic sensing instruments. Like the Minerva rovers, Mascot will also contain a swinging weight, letting it make surface hops.