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Explained: NASA’s OSIRIS-REx mission successfully picks samples from asteroid Bennu, but there is a problem

26th October, 2020 Science and Technology

Context: NASA’s OSIRIS-REx spacecraft, which was sent to collect rocks and dust from the surface of a near-Earth asteroid, is now so stuffed with cosmic rubble that a door was wedged open and precious samples are presently leaking into space.

So, what is happening with the mission now?

  • The spacecraft’s collector had gathered far more samples than anticipated.
  • The large rocks and rubble had jammed the flap that was designed to keep the samples inside the sample container.
  • Spacecraft’s robotic arm, also called the Touch-And-Go Sample Acquisition Mechanism or Tagsam, had made contact with the surface of the ancient Bennu asteroid.
  • The mission was required to collect a minimum of 2 ounces, or 60 grams, of rocks and dust from the asteroid’s surface. But researchers now believe that the arm captured at least 400 grams of material.

What is asteroid Bennu?

  • Asteroid Bennu was first discovered by a team from the NASA-funded Lincoln Near-Earth Asteroid Research team in 1999.
  • It was named after an Egyptian deity
  • Located around 200 million miles away from Earth, asteroid Bennu is around the size of the Empire State Building in New York.
  • 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.
  • In 2016, NASA launched the OSIRIS-REx — Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer — mission to collect samples of pebbles and dust from the surface of the ancient asteroid for the first time in history.
  • 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.
  • During this time it also surveyed the surface to identify sites from which it could collect 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 Earth.