OSIRIS-REx Spacecraft Arrives at Asteroid Bennu

• 04 Dec 2018

OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer) mission has arrived at asteroid Bennu after a two-year journey.

• OSIRIS-REx was launched from Cape Canaveral, Florida on September 8, 2016.
• The OSIRIS-REx mission is not the first to ever visit an asteroid and attempt a sample return — Japan has done (Hayabusa Mission) it before and Europe (Rosetta Mission) has managed to land on a comet.

Mission

• The Mission aims to study asteroid Bennu, collect a sample and return it to Earth in 2023.
• The mission will spend 2.5 years, mapping its surface and studying its composition.
• In mid-2020, scientists will direct Osiris-Rex to drop down to the asteroid and grab at least 60g of regolith, or "topsoil".
• This will be packed away in a sterile capsule to be returned home in 2023.

Mission Objective

• The OSIRIS-REx name is an acronym of the mission objectives, which are:
  • Origins: Return and analyze a pristine carbon-rich asteroid sample
  • Spectral Interpretation: Provide ground truth or direct observations for telescopic data of the entire asteroid population
  • Resource Identification: Map the chemistry and mineralogy of a primitive carbon-rich asteroid
  • Security: Measure the effect of sunlight on the orbit of a small asteroid, known as the Yarkovsky effect—the slight push created when the asteroid absorbs sunlight and re-emits that energy as heat
  • Regolith Explorer: Document the regolith (layer of loose, outer material) at the sampling site at scales down to the sub-centimeter

Significance of Mission

• Origins of the Solar System
  • In order to understand the origin and evolution of the solar system.
  • Bennu may have molecules of carbon and water, both of which are necessary for life.
  • As Earth formed, and afterward, objects like Bennu delivered these materials to our planet. By studying Bennu, we can better understand how life originated on earth.
• Protecting Earth
  • Bennu is one of the most potentially hazardous asteroids currently known to Earth. Bennu has a 1‐in‐2,700 chance of impacting earth during one of its close approaches to Earth in the late 22nd century.
  • Close observations by OSIRIS-REx will help get more information about Bennu's journey and help scientists working on safeguarding our planet against hazardous asteroids.
• Mining, LaunchPad, and Future Explorations
  • The mission will help to explore the possibility of using asteroids as refueling stations for spacecraft on the way to farther-flung destinations.
  • Asteroids might also help astronauts restock their supplies. For example, Bennu likely has water bound in clay minerals, which could perhaps one day be harvested for providing water to astronauts.
  • Asteroids contain a range of valuable minerals, there is a possibility of mining asteroids in the future.

About Bennu

• The asteroid was discovered by the Lincoln Near-Earth Asteroid Research (LINEAR) survey on September 11, 1999.
• It was originally named as 1999 RQ36.
• The name Bennu comes from an Egyptian deity related to the Sun, often depicted as a gray heron.
• Bennu is a 500-meter wide asteroid in an elliptical orbit around the sun. It is a carbonaceous asteroid composition including a large amount of carbon.

Why Bennu?

• It's close to Earth
  • Bennu’s orbit is close in proximity to Earth's, even crossing it. The asteroid makes its closest approach to Earth every 6 years.
  • It also circles the Sun nearly in the same plane as Earth, which makes it simple to launch the spacecraft out of Earth's plane and into Bennu's plane.
• It's the right size
  • Small asteroids, with diameters of 200 meters or less, spin very fast. This rapid spinning makes it difficult for a spacecraft to match an asteroid's velocity and collect samples.
  • Bennu's size makes it approachable and makes landing possible.