The original Hayabusa garnered worldwide attention after the near-miraculous completion of its mission. Following a mishap-laden encounter with its intended goal, the asteroid Itokawa, and the failure not only of its main propulsion systems but also of all but one of its ion guidance propulsion systems, it was initially thought lost in space.
Despite this, in a brilliant display of grit, skill, and improvisation, Japanese mission control successfully guided Hayabusa back to an earth flyby, and dropped a capsule containing material from Itokawa in the Australian desert.
The target this time is a roughly 3,000-foot diameter asteroid known by the rather unromantic scientific designation of 1999 JU3.
“This asteroid has been chosen because it is a type C Asteroid which is the most common type of asteroid in the solar system,” says the Japanese Space Commission.
Asteroids are small planets or celestial bodies. Some of them are large enough to have their own gravity and even their own moons. The largest are over a thousand kilometers in diameter, but they are rocks floating in space.
“American and European space probes have concentrated almost exclusively on taking samples from comets,” says Robert Forester, an astronomer who has been following the Japanese space efforts. “Unlike asteroids, which are small planetoids, comets can be thought of as big balls of ice and gas hurtling orbiting through the universe. We’re now finding out that they are made of much more minerals than we expected.”
In 2005, the NASA space probe Deep Impact fired an impactor (projectile) into a comet to determine its composition, and in 2006, NASA’s probe Stardust collected samples of cosmic dust from another comet, Wild 2, and parachuted them back to earth.”
The European Space Agency also has the Rosetta probe on the way to a comet. It will attempt to put a lander down on the comet sometime in 2014.”
However, Forester points out, Japan has been unique in its exploration of asteroids, which may hold clues to the origin of the universe. While NASA and ESA concentrate on comets, Japan has been concentrating its efforts almost exclusively on asteroids.
“Comets draw considerable attention because of they are so largely exposed of gas and ice,” Forester said. “There is some speculation that these gases and ice may contain some of the same primordial building blocks that lead to life on earth. But asteroids may have come into existence with the big bang, like the sun and the planets. They may contain some of the oldest matter in existence.”
The window of opportunity to launch Hayabusa 2 will be sometime during 2014, when the earth and 1999 JU3 reach optimal position for a launch. Hayabusa 2 should reach the asteroid, which is described as “roughly spherical” by 2018 and then, after landing on the surface and collecting material, begin its return voyage to earth in 2019.
Many changes are being made in Hayabusa 2 to avoid the problems that plagued the original Hayabusa. The ion engines will be upgraded to feature improved durability, and improvements in landing technology should insure a smooth set down on 1999 JU3.
The most significant change will be in the way Hayabusa 2 attempts to gather mineral samples from the asteroid. According to the Japan Space commission, it will not involve firing a projectile at close range into the asteroid, which may have been the cause of some of the problems with the original Hayabusa. This has also been the pattern followed by NASA and ESA in their comet probes.
Hayabusa 2 will use an entirely new approach: it will drop an explosive impactor designed to slowly descend to the surface of 1999 JU3 when Hayabusa 2 is around three hundred meters from the asteroid. After the impactor detonates, Hayabusa 2 will descend to the asteroid and collect samples from the scattered debris and dust.
If everything goes according to plan, Hayabusa 2 will return with perhaps the largest cache of material ever garnered on a robotic planetary mission. Both NASA and ESA probes, like the original Hayabusa probe have only brought back small amounts of material. The Hayabusa 2 mission could potentially supply important clues about the beginning of the universe.