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Current Affairs > Science and Technology > 2019-01-02 > Science and Technology

NASA’s OSIRIS-REx breaks record for smallest space object ever orbited

What in news:

·         OSIRIS-REx spacecraft successfully orbited around asteroid Bennu.

About news:

·         NASA’s OSIRIS-REx spacecraft broke a record after successfully entering into orbit around the asteroid Bennu — the smallest cosmic object ever to be orbited by a spacecraft.

·         While many on Earth prepared to welcome the New Year, NASA’s OSIRIS-REx spacecraft, 110 million kilometres away, carried out a single, eight-second burn of its thrusters, NASA said in a statement.

·         “With the navigation campaign coming to an end, we are looking forward to the scientific mapping and sample site selection phase of the mission,” said Laurette.

·         Inching around the asteroid at a snail’s pace, OSIRIS-REx’s first orbit marks a leap for humankind.

·         Never before has a spacecraft from Earth circled so close to such a small space object — one with barely enough gravity to keep a vehicle in a stable orbit.

·         The gravity of Bennu is so small, forces like solar radiation and thermal pressure from Bennu’s surface become much more relevant and can push the spacecraft around it

·         The spacecraft will circle Bennu about 1.75 kilometres from its centre, closer than any other spacecraft has come to its celestial object of study.

·         Previously the closest orbit of a planetary body was in May 2016, when the Rosetta spacecraft orbited about seven kilometers from the center of the comet 67P/Churyumov-Gerasimenko.

·         The comfortable distance is necessary to keep the spacecraft locked to Bennu, which has a gravity force only 5-millionths as strong as Earth’s.

·          The spacecraft is scheduled to orbit Bennu through mid-February at a leisurely 62 hours per orbit.

·         Now that the OSIRIS-REx spacecraft is closer to Bennu, physical details about the asteroid

·          orbit design is highly dependent on Bennu’s physical properties, such as its mass and gravity field.

·         As the team learned more about the asteroid,they incorporated new information to hone in on the final orbit design.

·         The simulations have played a critical role. The OSIRIS-REx mission, after all, was designed based on complex computer programs that predicted the properties of Bennu and how the spacecraft’s trajectory would behave.

·         This diligent preparation allowed the team to navigate the vehicle safely to Bennu in December and put some questions to rest and to fly over its poles and equatorm.

·         The spacecraft will perform a series of close flybys of Bennu for several months to take high-resolution images of every square inch of the asteroid to help select a sampling site.

·         During the summer of 2020, the spacecraft will briefly touch the surface of Bennu to retrieve a sample.

·         The OSIRIS-REx mission is scheduled to deliver the sample to Earth in September 2023.

OSIRIS-REx spacecraft

·         The OSIRIS-REx is a NASA asteroid study and sample-return mission.

·          The mission's main goal is to obtain a sample of at least 60 grams from 101955 Bennu, a carbonaceous near-Earth asteroid, and return the sample to Earth for a detailed analysis.

Bennu asteroid:

·         Bennu is a carbonaceous asteroid in the Apollo group discovered by the LINEAR Project on 11 September 1999.

·          Asteroid Bennu has a roughly spheroidal shape, resembling a spinning top. The direction of rotation about its axis is retrograde with respect to its orbit.

·         Preliminary spectroscopic surveys of the asteroid's surface by OSIRIS-REx spacecraft, detected the presence of the hydroxyl group likely bonded in the clay material of the asteroid.

Expected prelims question

Consider the following statements

1.       OSIRIS-Rex spacecraft was launched by NASA

2.       OSIRIS-REx spacecraft was launched over asteroid Bennu.

Which of the above statements are correct.

a)                   Only 1

b)                  Only 2

c)                   Both 1 and 2

d)                  None of the above

Ans – c

Expected mains question

Describe the features of Bennu Bennu asteroid. Analyse why do most of space explorations Carried out over asteroids and meteors.