The latest project, Hayabusa 2, is not an asteroid destruction mission – unlike the planet-destroying Death Star in ‘Star Wars,’ Hayabusa 2 is not primed to boom a giant hunk of rock out of existence. Instead, the probe’s so-called cannon is intended to put an artificial crater into the target, the C-type asteroid 1999 JU3, with a 4-pound projectile, exposing subsurface material. Hayabusa 2, which will have detached from the canon and gone to “hide behind the asteroid” while the cannon does the explosive work, will then sample the material, believed to be rich in water and organic matter.
The craft, set to depart in 2014, is expected to reach the asteroid in June 2018. It is due to return to Earth in December 2020.
Three years ago, Japan’s first iteration of the probe, the Hayabusa (“falcon,” in Japanese), made the first ever round-trip mission to an asteroid. Its seven-year trip to and from the Itokawa asteroid, a member of the common S-type of asteroids, brought back for Japan samples that would go on to answer an outstanding question in astronomy: why don’t meteorites that fall to Earth appear to come from the asteroid belt?
Well, it turns out they do, reported Hayabusa. Based on remote recordings of asteroid’s spectral colors, astronomers had once though that S-type asteroids were too red to be the source of meteorites. But, the Hayabusa team reported, the solar wind had been responsible for distorting the observed colors of asteroids – S-types were not so red, after all. In fact, Hayabusa’s asteroid dust samples turned out to be a compositional match to meteorites. Case closed.
In 2011, the scientific journal Science named the Hayabusa one of the year’s scientific breakthroughs. But it was a mission not without pitfalls. Before Hayabusa touched down and unfurled its asteroid samples, the world had been prepared to call the mission an abject failure.