Context
NASA’s Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) spacecraft will depart asteroid Bennu, and start its two-year long journey back to Earth.
About the OSIRIS-REx mission
- NASA’s first mission: To visit a near-Earth asteroid, survey its surface and to collect a sample from it.
- Sample collection: The spacecraft touched asteroid Bennu and collected samples of dust and pebbles.
- 7 year mission: The mission is essentially a seven-year-long voyage and it will conclude with at least 60 grams of samples are delivered back to the Earth.
- Launch: The mission was launched in 2016.
- It reached its target in 2018.
- Since then, the spacecraft was trying to match the velocity of the asteroid using small rocket thrusters.
- Instruments: The spacecraft contains five instruments to explore Bennu including cameras, a spectrometer and a laser altimeter.
What is asteroid?
- Asteroids are rocky objects which orbit the Sun.
- They much smaller than planets and are also called minor planets.
- There are around 994,383 known asteroids.
asteroid Bennu
- Bennu is a tall asteroid and located about 200 million miles away from the Earth.
- Bennu is said to have been born in the Main Asteroid belt between Mars and Jupiter and because of gravitational tugs from other celestial objects.
- Bennu is named after an Egyptian deity.
- The asteroid was discovered by NASA-funded Lincoln Near-Earth Asteroid Research team in 1999.
- Bennu is classified as a Near Earth Object (NEO).
- NEOs are comets and asteroids nudged by the gravitational attraction of nearby planets into orbits which allow them to enter the Earth’s neighbourhood.
- Bennu is a B-type asteroid which implies that it contains significant amounts of carbon and various other minerals.
- Because of the high carbon content, the asteroid reflects about 4% of the light that hits it, which is very low in comparison to Venus, which reflects about 65 per cent of the light and Earth that reflects about 30 per cent.
- There is a slight possibility that Bennu, might strike the Earth in the next century between the years 2175 and 2199.
Reason behind its study
- This is studied for information about the formation and history of planets and the sun because asteroids were formed at the same time as other objects in the solar system.
- Bennu is considered to be an ancient asteroid which has not gone much composition-altering change through billions of years.
- It means that below its surface lie chemicals and rocks from the birth of the solar system.
- It might give the clues about the origins of the solar system, the sun, the Earth and the other planets.
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How the spacecraft collected the sample in October 2020?
- Rock stirring: The spacecraft contacted the surface of the asteroid and fired a burst of nitrogen gas that stirred the rocks and soil.
- After the surface was disturbed, the spacecraft’s robotic arm captured some samples.
What will scientists do with the samples?
- Samples: The spacecraft will return in September 2023 and will bring back the largest sample collected by a NASA mission since the Apollo astronauts.
- The samples will be used to study the formation of the solar system and of habitable planets such as Earth.
