Following up on the near-loss of the Hayabusa I mission in 2003-10, the Japan Aerospace Exploration Agency (JAXA) will be sending Hayabusa 2 to collect samples from an asteroid in 2014. The name “Hayabusa” means “peregrine falcon” in Japanese.
Mission profile
Hayabusa 2 is planned to launch in July 2014, with arrival at its target asteroid in 2018. Up to three backup launch windows are available, with the last being in December 2015. If this deadline is missed, the next launch window will not happen for a decade.
The new target asteroid will be 162173 1999 JU3, a near-Earth asteroid which is approximately 0.6 miles in diameter. 162173 1999 JU3 is an Apollo asteroid, which means that its orbit crosses the Earth’s orbit and never goes too far away from it. This is the same kind of asteroid as Itokawa, which was the target asteroid for the Hayabusa 1 mission.
Unlike Itokawa, 162173 1999 JU3 is a C-type asteroid, which means that it is composed primarily of carbon. Carbonaceous asteroids make up at least 75% of known asteroids. The reason for choosing a carbonaceous asteroid this time is to search for organic carbon compounds, which may have been the source of life on Earth.
Hayabusa 2 will stay at the asteroid for 1-1/2 years. During this time, it will take samples from the surface and interior of the asteroid.
At the end of 2019, Hayabusa 2 will leave the asteroid. It should arrive back on Earth at the end of 2020.
Learning from Hayabusa 1
Most of Hayabusa 2’s technology has been upgraded from similar technology used in Hayabusa 1. This includes upgraded guidance and navigation technology, including new antennas and attitude-control systems. The reaction wheels which controlled the X-axis and Y-axis attitude movement failed at one point during the Hayabusa 1 mission.
Upon arrival at Itokawa, Hayabusa 1’s “bullets” failed to launch correctly. Instead, Hayabusa 2 will launch a slow-moving impactor at the surface of the asteroid. The resulting small crater will reveal materials from the inside of the asteroid, which have not been altered by the constant bombardment of the solar wind. Hayabusa 2 will have two different methods of collecting these samples, in case the first method fails.
Like Hayabusa 1, Hayabusa 2 will use ion engines for its primary propulsion. Hayabusa 1 was the first space mission to use ion engines continuously for more than 1,000 hours. However, a solar flare during the earlier mission damaged the solar cells, which reduced the efficiency of the ion engines and delayed Hayabusa 1’s arrival at Itokawa. The Hayabusa 2 mission is scheduled to take place close to solar maximum, which will increase the risk.
