OSIRIS-REX MISSION
Context
- Recently, NASA’s OSIRIS-REx spacecraft briefly touched down on the surface of asteroid Bennu to collect rock and dust samples.
More About OSIRIS-REx Mission
- This is NASA’s first mission meant to return a sample from the ancient 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 mission promises to bring the largest amount of extraterrestrial material back to our planet since the Apollo era.
- 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. It also utilised this time to survey the surface and identify potential sites to take samples.
- 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.
More About Asteroid Bennu
- Bennu is an ancient asteroid, currently more than 200 million miles from Earth.
- Bennu is classified as a B-type asteroid, which means it contains a lot of carbon in and along with its various minerals.
- Bennu’s carbon content creates a surface on the asteroid that reflects about four percent of the light that hits it. For contrast, the solar system’s brightest planet, Venus, reflects around 65 percent of incoming sunlight, and Earth reflects about 30 percent.
- Bennu is a carbonaceous asteroid that hasn’t
- undergone drastic, composition-altering change, meaning that on and below its deeper-than-pitch-black surface are chemicals and rocks from the birth of the solar system.
- Bennu has been (mostly) undisturbed for billions of years. Not only is it conveniently close and carbonaceous, it is also so primitive that scientists calculated it formed in the first 10 million years of our solar system’s history — over 4.5 billion years ago.
WHAT IS AN ASTEROID?
- Asteroids are rocky objects that orbit the Sun, much smaller than planets. They are also called minor planets. According to NASA, 994,383 is the count of known asteroids, the remnants from the formation of the solar system over 4.6 billion years ago.
- Asteroids are divided into three classes.
- First, those found in the main asteroid belt between Mars and Jupiter, which is estimated to contain somewhere between 1.1-1.9 million asteroids.
- The second group is that of 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.
- The third classification is 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).