NASA’s OSIRIS-REx begins asteroid operations campaign

Washington, August 27: After an almost two-year journey, NASA’s asteroid sampling spacecraft, the Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx), caught its first glimpse of asteroid Bennu last week and began the final approach toward its target. Kicking off the mission’s asteroid operations campaign on Aug. 17, the spacecraft’s PolyCam camera obtained the image from a distance of 1.4 million miles (2.2 million km).

OSIRIS-REx is NASA’s first mission to visit a near-Earth asteroid, survey the surface, collect a sample and deliver it safely back to Earth. The spacecraft has traveled approximately 1.1 billion miles (1.8 billion km) since its Sept. 8, 2016, launch and is scheduled to arrive at Bennu on Dec. 3.

As OSIRIS-REx approaches the asteroid, the spacecraft will use its science instruments to gather information about Bennu and prepare for arrival. The spacecraft’s science payload comprises the OCAMS camera suite (PolyCam, MapCam, and SamCam), the OTES thermal spectrometer, the OVIRS visible and infrared spectrometer, the OLA laser altimeter, and the REXIS x-ray spectrometer.

During the mission’s approach phase, OSIRIS-REx will:

• regularly observe the area around the asteroid to search for dust plumes and natural satellites, and study Bennu’s light and spectral properties;
  
  
• execute a series of four asteroid approach maneuvers, beginning on Oct. 1, slowing the spacecraft to match Bennu's orbit around the Sun;
  
  
• jettison the protective cover of the spacecraft’s sampling arm in mid-October and subsequently extend and image the arm for the first time in flight; and
  
  
• use OCAMS to reveal the asteroid’s overall shape in late-October and begin detecting Bennu’s surface features in mid-November.

After arrival at Bennu, the spacecraft will spend the first month performing flybys of Bennu’s north pole, equator and south pole, at distances ranging between 11.8 and 4.4 miles (19 and 7 km) from the asteroid. These maneuvers will allow for the first direct measurement of Bennu’s mass as well as close-up observations of the surface. These trajectories will also provide the mission's navigation team with experience navigating near the asteroid.