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Asteroid Bennu

Asteroid Bennu

Context:

NASA’s OSIRIS-REx spacecraft touched asteroid Bennu, from where it is meant to collect samples of dust and pebbles and deliver them back to Earth in 2023.

  • OSIRIS-REx stands for Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer.
  • The asteroid was named after an Egyptian deity by a nine-year-old boy from North Carolina in 2013. 

Asteroids:

  • These are rocky objects that orbit the Sun, much smaller than planets. They are also called minor planets. 
  • According to NASA, there are around 994,383 known asteroids, the remnants from the formation of the solar system over 4.6 billion years ago.
  • Asteroids are divided into three classes:
    1. Tose found in the main asteroid belt between Mars and Jupiter, which are estimated to contain somewhere between 1.1-1.9 million asteroids.
    2. Trojans: These are asteroids that share an orbit with a larger planet. NASA reports the presence of Jupiter, Neptune, and Mars trojans. In 2011, they reported an Earth trojan as well.
    3. Near-Earth Asteroids (NEA): These have orbits that pass close by the Earth. Those that cross the Earth’s orbit are called Earth-crossers. More than 10,000 such asteroids are known, out of which over 1,400 are classified as potentially hazardous asteroids (PHAs).

OSIRIS-REx mission:

  • This is NASA’s first mission meant to return a sample from the ancient asteroid. 
  • The mission was launched in 2016, it reached its target in 2018 and since then, the spacecraft has been trying to match the velocity of the asteroid using small rocket thrusters to rendezvous it. 
  • The mission is essentially a seven-year-long voyage and will conclude when at least 60 grams of samples are delivered back to the Earth.
  • The mission aims to bring the largest amount of extraterrestrial material back to our planet since the Apollo era.

Recent developments: 

  • Recently, the spacecraft’s robotic arm called the Touch-And-Go Sample Acquisition Mechanism (TAGSAM), made an attempt to “TAG” the asteroid at a sample site which was no bigger than a few parking spaces and collected a sample.
  • The spacecraft contains five instruments meant to explore Bennu including cameras, a spectrometer, and a laser altimeter.
    • The departure window for the mission will open up in 2021, after which it will take over two years to reach back to Earth.

Asteroid Bennu:

  • Bennu is an asteroid about as tall as the Empire State Building and located at a distance of about 200 million miles away from the Earth. 
  • Scientists study asteroids to look for information about the formation and history of planets and the sun since asteroids were formed at the same time as other objects in the solar system.
    • Another reason for tracking them is to look for asteroids that might be potentially hazardous.
  • Bennu hasn’t undergone drastic changes since its formation over billions of years ago and therefore it contains chemicals and rocks dating back to the birth of the solar system.
    • It is also relatively close to the Earth.

Source: Indian Express