[meteorite-list] Hayabusa 2 Launches on Audacious Asteroid Adventure

[Ron Baalke]

http://spaceflightnow.com/2014/12/03/hayabusa-2-launches-on-audacious-asteroid-adventure/

Hayabusa 2 launches on audacious asteroid adventure
by Stephen Clark
Spaceflight Now
December 3, 2014

A Japanese H-2A launcher blasted off from an idyllic island spaceport 
Tuesday, dispatching a daring six-year expedition to bring a piece of 
an asteroid back to Earth.

The Hayabusa 2 mission's roundtrip voyage began at 0422 GMT Wednesday 
(11:22 p.m. EST Tuesday) with a thunderous ascent from Tanegashima Space 
Center in southern Japan.

The 1,300-pound spacecraft rode a hydrogen-fueled H-2A rocket through 
clouds hanging over the seaside spaceport, leaving a twisting column of 
exhaust in its wake before disappearing hundreds of miles over the Pacific 
Ocean.

The rocket's upper stage engine fired two times to accelerate Hayabusa 
2 on a speedy departure fast enough to break free of the pull of Earth's 
gravity.

The robotic explorer, packed with four stowaway landers to be deployed 
to the asteroid's surface, separated from the H-2A rocket at 0609 GMT 
(1:09 a.m. EST). Applause could be heard in a live webcast of the launch 
provided by the Japan Aerospace Exploration Agency, which manages the 
Hayabusa 2 mission.

The launch marked the opening chapter in the most ambitious mission to 
an asteroid ever attempted. The roundtrip journey will take six years 
to complete, and Hayabusa 2 promises to expand scientists' understanding 
of how asteroids may have seeded Earth with water and organic molecules, 
the building blocks of life.

Hayabusa 2 is heading for asteroid 1999 JU3, a carbon-rich world just 
900 meters - about 3,000 feet - across with a tenuous gravity field 60,000 
times weaker than Earth's.

The mission follows up on the achievements of Japan's Hayabusa 1 probe, 
which made the first roundtrip flight to an asteroid from 2003 to 2010. 
The first Hayabusa mission encountered several crippling problems, including 
a fuel leak, failures in its pointing system, and a glitch with the craft's 
sample collection system.

Despite the challenges, the spacecraft returned to Earth in 2010 - a few 
years late and carrying a fraction of the asteroid specimens intended. 
But Japanese scientists found microscopic samples from asteroid Itokawa 
- Hayabusa 1's research subject - inside the probe's landing vehicle.

The success vaulted Japan into the big leagues of solar system exploration.

"Many scientific milestones have been achieved from asteroid observations 
and samples from the asteroid Itokawa," said Tetsuo Tanaka, associate 
director general of JAXA's Lunar and Planetary Exploration Program Group. 
"Going to a far-off asteroid and returning with samples from it for the 
first time, these are tremendous technological challenges and our success 
in meeting them has brought worldwise admiration."

"For the Hayabusa 2 project, Japan's development of its own deep space 
exploration technology aims to lead the world in that technical field," 
Tanaka said. "The Hayabusa 2 project sets new challenges for Japan's unique 
technologies. How we face those challenges and how we use (the) project 
results will surely bring new impacts to the world."
Artist's concept of the Hayabusa 2 spacecraft at asteroid 1999 JU3. Credit: 
JAXA

But Hayabusa's troubles meant it was prudent for engineers to make changes 
on Hayabusa 2.

"We changed a lot of parts on Hayabusa 2," said Hitoshi Kuninaka, JAXA's 
Hayabusa 2 program manager. "We installed four reaction wheels, and Hayabusa 
1 had only three. The sampling system also has some improvements. Our 
operations software was upgraded for better proximity operations around 
the asteroid."

Hayabusa 2's electrically-powered ion engines were upgraded to produce 
more thrust, and engineers installed a Ka-band antenna to beam data back 
to Earth at four times the rate possible on the first Hayabusa mission.

"Many scientific milestones have been schieved from asteroid oobservations 
and samples from the asteroid itokawa. going to a far off asteroid and 
returning with samples from it for the first time. these are tremendous 
technological challenges and our success in meeting them has brought worldwise 
admiration.

Japan has gained unique exploration experience through projects like Yayabusa, 
Kaguya and Kkaros.

For the Hayabusa 2 project, Japan's development of its own deep space 
exploration technology aims to lead the world in that technical field.

he Hayabusa 2 project sets new challenges for Japan's unique technologies. 
Wow we face those challenges and how we use project results will surely 
bring new impacts to the world.

The spacecraft will arrive at the asteroid in June 2018 after swinging 
by Earth late next year to get a boost to the mission's destination, which 
circles the sun between the orbits of Earth and Mars.

The probe will initially park itself 20 kilometers, or about 12 miles, 
from the asteroid for a comprehensive survey with a set of spectrometers, 
cameras, and other sensors to map the tiny world.

Then scientists will start to look for suitable sites on the asteroid 
to put down four diminutive landing drones and scoop up samples for return 
to Earth.

Hayabusa 2 will spend a year-and-a-half at asteroid 1999 JU3, enough time 
for the probe to pick up rock specimens from three different locations 
on the unexplored asteroid.

One of the samples is supposed to come from material excavated from beneath 
the asteroid's surface. Hayabusa 2 will use explosives to fire a copper 
impactor laden into the asteroid to carve an artificial crater, exposing 
underground pristine rocks for the probe to pick up during a touch-and-go 
maneuver.

"The most difficult operations are, I think, the impactor operations," 
Kuninaka said. "Scientists want to get materials from inside of the asteroid, 
so we developed the impactor - That is a very difficult operation. Once 
we release the impactor from the asteroid, it will be ignited about 40 
minutes later. We cannot stop that ignition, so before the ignition the 
spacecraft will do an escape maneuver to the other side of the asteroid, 
and the time is very limited. We have to do the escape maneuver so the 
spacecraft will avoid serious damage from the impactor. I think that is 
one of the most difficult operations we have ever done."

The spacecraft's sampling mechanism works by shooting a small bullet into 
the asteroid after it dips down to the surface. When the bullet fires 
while Hayabusa 2's sampling funnel is in contact with the asteroid, engineers 
believe bits of gravely rock will be blasted through a tube into a collection 
chamber for storage inside the mission's return capsule.

Hayabusa 2 carries four landers, including a 22-pound robot named MASCOT 
built by the same team that managed the Philae comet lander that touched 
down on comet 67P/Churyumov-Gerasimenko on Nov. 12.

Three other landing craft built in Japan will also descend to the asteroid 
during Hayabusa 2's mission.

The landers are mobile and will use mechanisms to hop across the asteroid 
to study its environment from several locations.

"We are going to operate simultaneously a large group of robotics on the 
surface of the asteroid," Kuninaka said. "That will be an immense engineering 
challenge to operate many robots at the same time on the asteroid."

Once the mission's work at the asteroid is complete, Hayabusa 2 will leave 
and heard for Earth in December 2019.

Hayabusa 2 will release a container with the asteroid samples for a blazing 
re-entry through Earth's atmosphere for a parachute-assisted landing in 
the Australian outback in December 2020.

In an interview with Spaceflight Now before the launch, Kuninaka said 
Hayabusa 2 has a dual purpose as a machine for scientific discovery and 
a testbed for new technologies that could advance space exploration.

"Learning about asteroids is important for the future of space exploration,"
Kuninaka said. "This is a difficult mission, but in order for humans to 
expand from Earth into space, it will be necessary to meet challenges. 
We need a lot of technology and information about the solar system, and 
Hayabusa 2 will make a big step in these areas to help us be ready to 
plan and collaborate in the next step of space exploration."