- Awareness in space.
What to study?
For Prelims and Mains: OSIRIS-Rex mission and facts on asteroid bennu.
Context: The US space agency NASA has announced that its asteroid probe OSIRIS-REx set a new record for the closest-ever orbit of a planetary body made by a man-made spacecraft.
The recent maneuver has placed the spacecraft into an orbit 680 meters above the asteroid Bennu’s surface for about seven weeks.
About the mission:
OSIRIS-Rex stands for Origins, Spectral Interpretation, Resource Identification, 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.
Why was Bennu chosen?
Bennu was selected for a the OSIRIS-REx mission from over 500,000 known asteroids, due to it fitting a number of key criteria. These include:
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: Small asteroids, those less than 200m in diameter, typically spin much faster than larger asteroids, meaning the regolith material can be ejected into space. Bennu is around 500m in diameter, so rotates slowly enough to ensure that the regolith stays on its surface.
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.