[meteorite-list] Japan Nears Launch of Hayabusa 2 Probe to Retrieve Asteroid Samples

[Ron Baalke]

http://www.spaceflightnow.com/news/n1409/01hayabusa2/

Japan nears launch of probe to retrieve asteroid samples
BY STEPHEN CLARK
SPACEFLIGHT NOW
September 1, 2014

The Hayabusa 2 asteroid probe, on track for liftoff this winter, will 
be shipped to its island launch base at the end of September for final 
preparations to start the most audacious space exploration mission ever 
attempted by Japan.
 
The mission will take off on top of an H-2A launcher as soon as December, 
fly to an asteroid scientists believe is a relic from the genesis of the 
solar system, drop a European-built lander, and return to Earth in 2020 
with extraterrestrial rock samples.

The Japan Aerospace Exploration Agency revealed Hayabusa 2 to media Sunday 
as it neared the finish line in a four-year effort to design, construct 
and test the spacecraft.

Japanese officials have not announced the target launch date, but they 
say the mission is on schedule to lift off as soon as December in a narrow 
window when Earth and Hayabusa 2's target asteroid are properly positioned 
to make the journey possible.

Backup launch windows are available in June and December 2015.

The spacecraft, now almost fully assembled for flight, will soon wrap 
up testing at JAXA's Sagamihara campus near Tokyo, according to Hitoshi 
Kuninaka, Hayabusa 2's project manager.

"At the end of September, the spacecraft will be transported to Tanegashima," 
Kuninaka said.

Hayabusa 2's launch is next in line for liftoff from the Tanegashima Space 
Center -- located on Tanegashima Island in southwestern Japan -- after 
an Oct. 7 launch of the Himawari 8 weather satellite.

Once the spacecraft arrives at the launch site, Kuninaka said technicians 
will install pyrotechnic charges for its mission, which include explosives 
to excavate material from beneath the asteroid's surface. Ground crews 
will also add the mission's flight batteries and fill the probe with xenon 
gas and hydrazine propellant.

JAXA says the Hayabusa 2 mission's cost is 28.9 billion yen, or about 
$275 million.

Hayabusa 2's launch follows four years after its namesake -- the hard-luck 
Hayabusa mission -- returned to Earth with microscopic specimens collected 
from asteroid Itokawa.

Engineers designed Hayabusa with upgrades to expand its scientific payoff 
and increase its chance for success.

Hayabusa 2 carries four xenon-fueled ion thrusters for the voyage to asteroid 
1999 JU3, an object with a diameter of about 3,200 feet that researchers 
believe is made of primitive rock left over from the ancient solar system.

After a swingby of Earth in late 2015 to get a gravity boost, the 1,320-pound 
craft will arrive at 1999 JU3 in June 2018 and loiter around the asteroid 
for about 18 months.

Once it arrives at asteroid 1999 JU3, Hayabusa 2 will survey the rock 
with an array of instruments, including imagers, a spectrometer, and a 
terrain-mapping altimeter.

The craft will also release a small Japanese rover named MINERVA to hop 
across the surface of the asteroid and deploy the MASCOT lander developed 
by the German Aerospace Center, or DLR.

Hayabusa spent about three months exploring Itokawa, an asteroid about 
half the size of 1999 JU3.

Hayabusa 2's destination is a different type of miniature world than Itokawa. 
Asteroid 1999 JU3 is a C-type asteroid, a classification of primitive 
objects made of organic and hydrated minerals.

Itokawa is an S-type asteroid composed of rocks and metals heated and 
modified over the solar system's 4.5 billion year history, causing the 
material to lose chemical markers left over from the dawn of the solar 
system.

Scientists expect the Hayabusa 2 samples to hold a record of the tumultuous 
early phases of the solar system's formation, including the basic building 
blocks of life such as amino acids.

Hayabusa 2 will collect up to three samples from 1999 JU3, including material 
blasted from beneath the asteroid's surface by a explosive grapefruit-sized 
copper impactor released from the mothership.

Depending on the texture of the rocks on 1999 JU3, Hayabusa 2 should pick 
up between a gram and several grams of samples.

After up to three close approaches to acquire samples, Hayabusa 2 will 
depart the asteroid in December 2019 and deploy a sample-bearing re-entry 
capsule into Earth's atmosphere in December 2020.