What is asteroid Bennu, and why is NASA studying it?

Asteroids are small, rocky objects that orbit the Sun. Although asteroids orbit the Sun like planets, they are much smaller than planets. They are also called minor planets.

First are the kind which are found in the main asteroid belt between Mars and Jupiter, which is estimated to contain somewhere between 1.1-1.9 million asteroids.
Second are called the trojans, which 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.
Third are Near-Earth Asteroids (NEA), which 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).

bennu

It was discovered in 1999 by NASA and has been named after an Egyptian deity.
It is about 200 million miles away from the Earth.
This asteroid is a B-type asteroid, implying that it contains significant amounts of carbon and various other minerals. It reflects only 4% of light which falls on it.

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This is NASA’s first mission to extract material from the Bennu asteroid.
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 spacecraft contains five instruments meant to explore Bennu including cameras, a spectrometer and a laser altimeter.
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 get itself attached to the asteroid.
It also analysed the places where it can take out the samples.
On October 20th 2020, the spacecraft made contact with the Bennu asteroid. It used Touch-And-Go Sample Acquisition Mechanism (TAGSAM) to tag with the asteroid.
The spacecraft will detach with the asteroid in 2021 and will return back to the earth in 2023.

The study will give information about the formation and history of planets and the sun since asteroids were formed at the same time.
Bennuasteroid 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.
Tracking these asteroids may also be useful as it can be hazardous in the future. There is a slight possibility that Bennu, which is classified as a Near Earth Object (NEO), might strike the Earth in the next century, between the years 2175 and 2199

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