OSIRIS-Rex
is the first-ever US mission designed to visit an asteroid and return a sample
of its dust back to Earth. OSIRIS-Rex stands for Origins, Spectral
Interpretation, Resource Identification, and Security-Regolith Explorer.
OSIRIS-Rex
is the third mission in NASA’s New Frontiers program, which previously sent the
New Horizons spacecraft zooming by Pluto and the Juno spacecraft into orbit
around Jupiter.
Orbiting
Bennu
Bennu
is an asteroid. Bennu was selected for a the OSIRIS-Rex mission from over
500,000 known asteroids, due to it fitting a number of key criteria.
The
criteria included – proximity to the Earth, size, composition etc.
Proximity
to Earth: In order for OSIRIS-Rex to reach its
destination in a reasonable timeframe, NASA needed to find an asteroid
which had a similar orbit to Earth.
Size:
Bennu is around 500m in diameter, so rotates
slowly enough to ensure that the regolith stays on its surface. Regolith meant the layer of unconsolidated solid material covering the
bedrock of a planet. Smaller asteroid spin faster.
Composition: Bennu is a primitive asteroid, meaning it hasn’t significantly
changed since the beginning of the Solar System (over 4 billion years ago). It
is also very carbon-rich, meaning it may contain organic molecules, which could
have been precursors to life on Earth.
Additionally,
Bennu is of interest as it is a Potentially Hazardous Asteroid (PHA).
Every 6 years, Bennu’s orbit brings it within 200,000 miles of the Earth, which
means it has a high probability of impacting Earth in the late 22nd Century.
The
unmanned Spaceship
The
$800 million (roughly Rs. 5,600 crores) unmanned spaceship launched two years
ago from Cape Canaveral, Florida and arrived December 3 at its destination,
some 70 million miles (110 million kilometers) away.
The
plan is for OSIRIS-Rex to orbit Bennu through mid-February, using a suite of
five scientific instruments to map the asteroid in high resolution to help
scientists decide precisely where to sample from.
It
was launched in September 2016, and it will reach in 2020. It will use its
robotic arm and touch the asteroid in a maneuver Rich Kuhns, OSIRIS-Rex program
manager with Lockheed Martin Space Systems in Denver, described as a “gentle
high-five.”
Using
a circular device much like a car’s air filter, and a reverse vacuum to stir up
and collect dust, the device aims to grab about two ounces (60 grams) of
material from the asteroid’s surface, and return it to Earth in 2023.
