- March 21, 2019
- Posted by: InsightsIAS
- Category: INSIGHTS
- Awareness in space.
What to study?
For Prelims and Mains: OSIRIS-Rex mission and facts on asteroid bennu.
Context: NASA’s OSIRIS-REx spacecraft has detected particle plumes ejecting off of the surface of asteroid Bennu. That makes Bennu an active asteroid that is regularly ejecting material into space, which is rare. This is the first time scientists have had close-up observations of particle plumes erupting from an asteroid’s surface.
- The particles range from centimeters to 10s of centimeters, and some of them are slow-moving while others are quickly making their way through interstellar space. Some fall back onto the surface, while others go into orbit around it, like small satellites. The researchers don’t currently understand why this is happening, but it poses no risk to the spacecraft.
OSIRIS-REx’s instruments have confirmed that hydrated minerals, including magnetite, are abundant and widespread on the asteroid. The asteroid is full of valuable materials that may even contain clues about how life began. Bennu is essentially a leftover from the formation of our solar system billions of years ago, although some of the minerals inside it could be even older.
OSIRIS-Rex is the first-ever US mission designed to visit an asteroid and return a sample of its dust back to Earth. 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 kilometres) away.
The plan is for OSIRIS-REx to orbit Bennu, using a suite of five scientific instruments to map the asteroid in high resolution to help scientists decide precisely where to sample from.
- Then, in 2020, it will reach out with 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.
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.