Japanese government officials last week gave the green light to Hayabusa 2, a robotic explorer due for launch in 2014 on a journey to retrieve and return rocks from a near-Earth asteroid.

Artist's concept of the Hayabusa 2 spacecraft approaching the target asteroid. Credit: Akihiro Ikeshita/JAXA
 
The Space Activities Commission, a board governing funding for the Japanese space program, formally approved the Hayabusa 2 mission last week. The decision came after a 2010 ruling that directed the Japan Aerospace Exploration Agency to continue preliminary design of the probe.

Launch of Hayabusa 2 must occur in 2014 to reach asteroid 1999 JU3, the mission's 3,000-foot-diameter target. Asteroid 1999 JU3, which is still awaiting a name, is a C-type body, the most common form of asteroid in the solar system. Observations by telescopes on Earth indicate the asteroid is roughly spherical and has dark features.

The probe would reach the asteroid in mid-2018 and depart in December 2019. Landing on Earth is expected at the end of 2020, according to JAXA.

Japan is working on a tight schedule and budget to develop the spacecraft in time for the narrow launch window, which is timed for when the asteroid is in the right position relative to Earth. JAXA officials say a back-up launch opportunity exists in 2015, but the mission would have to wait a decade longer to get off the ground if the probe misses the secondary window.

The project will receive $39 million in the Japanese fiscal year beginning April 1, according to documents released by the Space Activities Commission.

JAXA previously reported the Hayabusa 2 mission's total cost will be more than $200 million.

NEC Corp. of Tokyo announced Jan. 25 it was beginning system design of the 1,300-pound spacecraft, its Ka-band communications system and an intermediate infrared camera. NEC was the builder of the Hayabusa probe, which blasted off in 2003 and returned to Earth with microscopic asteroid samples in 2010.

Hayabusa's sample-collection device malfunctioned, and the craft was crippled by a fuel leak and failures of reaction wheels. But the probe limped back to Earth with an ion propulsion system, jettisoning a canister that parachuted to a soft landing in Australia.

Hayabusa's sample return capsule landed in Australia in June 2010. Credit: JAXA
 
Inside the capsule, researchers found tiny particles of material from asteroid Itokawa, a potato-shaped rock about the size of a city block. The initial research shows the samples inspected contain no organic molecules. Scientists also say the analysis confirms the rocks at Itokawa were formed 4.6 billion years ago at the dawn of the solar system.

Hayabusa 2 will attempt to correct the flaws that hampered Hayabusa's voyage, according to JAXA.

The next mission will feature more durable ion engines, upgraded guidance and navigation technology to ensure a smooth landing on asteroid 1999 JU3, and new antennas and attitude control systems.

Hayabusa 2's sample collection method is also being revamped after problems during Hayabusa's approach to Itokawa in late 2005.

Instead of firing a high-speed kinetic projectile at close range into the asteroid, as Hayabusa was supposed to do, Hayabusa 2 will drop an impactor about 1,000 feet from the surface. After descending slowly, the impactor will detonate once it reaches the asteroid, scattering bits of rock and exposing subsurface material.

Once the dust settles, Hayabusa 2 will approach the impact site and collect rocks with a horn leading into a sample holding chamber. If all goes according to plan, the mission should return a more sizable cache of samples than Hayabusa.