[meteorite-list] Japan's Hayabusa 2 Asteorid Mission Checks Out

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 9 Mar 2015 16:29:00 -0700 (PDT)
Message-ID: <201503092329.t29NT0PZ029212_at_zagami.jpl.nasa.gov>

http://spaceflightnow.com/2015/03/09/japans-hayabusa-2-asteroid-mission-checks-out/

Japan's Hayabusa 2 asteroid mission checks out
by Stephen Clark
SpaceFlight Now
March 9, 2015

Three months into an interplanetary cruise expected to last three-and-a-half
years, Japan's $300 million Hayabusa 2 mission is in good health as it
begins an ion-powered pursuit of an asteroid to return a piece of it to
Earth.

The robotic spacecraft is already traveling more than 20 million miles
from Earth after launching Dec. 3, and Japanese officials say the probe
has passed health checks and is ready for the long-distance journey ahead.

The Hayabusa 2 spacecraft "completed its initial functional confirmation
period on March 2, 2015, as all scheduled checkout and evaluation of acquired
data were completed," the Japan Aerospace Exploration Agency said in a
statement. "The explorer has been under inspection for about three months
after its launch on Dec. 3, 2014."

The probe carries four ion thrusters to nudge it on course toward 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 engines produce little thrust, but the units can be operated for thousands
of hours, building up energy to reshape Hayabusa 2's path around the sun.

JAXA says two of the ion engines will fire for about 400 hours in March
to give the spacecraft a boost. Two thrusters will be operated again in
early June.

The two periods of near-continuous propulsion will change the probe's
velocity by about 60 meters per second, or 134 mph, to align Hayabusa
2 with an encounter with Earth in December. The close flyby of Earth will
use the planet's gravity to slingshot Hayabusa 2 toward its destination,
where it is due to arrive in June 2018 after more firings of the craft's
ion engines.

Since Hayabusa 2's launch in early December, ground controllers tested
the probe's X-band and Ka-band communications systems, batteries, science
instruments, reaction wheels, and all four ion engines. Hayabusa 2 also
extended its sampling device in preparation for scooping up material at
the asteroid.

[Graphic]
Diagram of the positions of Earth, Hayabusa 2, and asteroid 1999 JU3 as
of March 3, 2015. Credit: JAXA

Engineers tested Hayabusa 2's German-built lander named MASCOT built by
the same team that managed the Philae comet lander, which was carried
aboard Europe's Rosetta spacecraft and touched down on comet
67P/Churyumov-Gerasimenko in November.

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.

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.

Once the mission's work at the asteroid is complete, Hayabusa 2 will leave
and head 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.
Received on Mon 09 Mar 2015 07:29:00 PM PDT