[meteorite-list] NASA Plans to Visit a Near-Earth Asteroid with OSIRIS-RE

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue, 16 Aug 2011 16:27:21 -0700 (PDT)
Message-ID: <201108162327.p7GNRLkr017549_at_zagami.jpl.nasa.gov>

http://science.nasa.gov/science-news/science-at-nasa/2011/16aug_osirisrex/

NASA Plans to Visit a Near-Earth Asteroid
NASA Science News
August 16, 2011

In a few years a NASA spacecraft will seek the
building blocks of life in a shovelful of asteroid dirt. The
OSIRIS-REx spacecraft, targeted for launch in September 2016, will
intercept asteroid 1999 RQ36, orbit it for a year, and then reach out a
robotic arm to touch its surface.

"We call it 'touch and go,'" explains principal investigator Michael
Drake of the University of Arizona. "OSIRIS-REx will approach the
surface at 0.1 m/sec (only 0.2 mph, less than a tenth of walking pace)
and, without landing, stretch out its arm equipped with a sample
collector. We'll simply agitate the asteroid's surface with ultra-pure
nitrogen to stir up material for capture."

Asteroids appear to be as lifeless as Yorick's skull, yet material
captured from 1999 RQ36 could hold clues to life's origin on Earth.

Some scientists believe Earth's surface was sterilized soon after the
planet was formed some 4.5 billion years ago. Planetoids and other
debris left over from the genesis of planets pummeled Earth, turning it
into a cratered wasteland. The tremendous kinetic energy from the
collisions heated Earth to the boiling point.

"Earth at 'time zero' had a steam atmosphere that was wrung out to make
a boiling hot ocean," says Drake. "Imagine standing on a lava lake in
Hawaii, but it's a planet-wide, 600 mile deep lake. You and everything
else, including any organics and any one-celled organisms, would be
converted to carbon dioxide and water. Gone."

In this scenario, an infusion of organics from elsewhere might be
required to ignite life here. The building blocks for life on our planet
may have come, at least in part, from asteroids.

"Observations by ground-based telescopes suggest that asteroid 1999 RQ36
has a wealth of carbon-based compounds, but we don't know exactly what
is there. Are there amino acids? To find out, we need to bring a sample
home where we have sophisticated, exquisitely precise instruments, plus
the ability to react to new discoveries."

Obtaining that sample is a key part of OSIRIS-REx's mission.

Upon reaching 1999 RQ36 in 2019, the spacecraft's suite of cameras and
instruments will spend a year photographing the asteroid and measuring
its surface topography, composition, and thermal emissions while its
radio provides mass and gravity field maps. This information will
increase our understanding of asteroids as well as help the mission team
select the most promising sample site.

Like the ancient Egyptian god Osiris, the OSIRIS-REx mission is
associated with death as well as life, with both our destiny and our
origin. That's because 1999 RQ36 is the Near Earth Object "Most Likely
to Succeed" ??? in affecting our destiny, that is. It has a 1/1800 chance
of hitting Earth by the 22nd century.

Evidence suggests that a 6-mile wide asteroid smashed into Earth about
65 million years ago, wiping out the dinosaurs and altering the history
of life. Instead of dinosaurs prevailing, mammals flourished, evolving
into humans.

"We're the first species that can mitigate asteroid extinction," notes
Drake. "With enough information, we can project the orbit of a
threatening asteroid."

If researchers can track an NEO's precise path, they can devise a way to
nudge the object out of a collision course with Earth. OSIRIS-REx wil
help NASA learn to navigate near an asteroid, laying the groundwork for
landing on one. That could be pretty tricky, considering asteroids like
1999 RQ36 have so little gravity.

"If you simply pushed your finger into the surface, you'd fly off into
space, disappear, and never come back!"

OSIRIS-REx, however, will hang close, and its cameras will give us
window seats to watch its delicate sampling maneuvers. The mission team
plans near-live coverage of the operations. But the real action starts,
says Drake, when the sample is returned to Earth in 2023.

A future story from Science at NASA will explain how the sample will be
handled upon return and lay out some of the experiments researchers will
do with it. Stay tuned.


Author: Dauna Coulter
Editor: Dr. Tony Phillips
Credit: Science at NASA
Received on Tue 16 Aug 2011 07:27:21 PM PDT