Today (Sept. 22, 2017), NASA's asteroid-hunting spacecraft, Origins-Spectral Interpretation-Resource Identification-Security-Regolith Explorer (OSIRIS-REx), will fly by Earth using the planet's gravitational force to slingshot itself back out into space into asteroid Bennu's orbital plane. This maneuver, known as an Earth gravity assist, will put OSIRIS-REx on course to visit Bennu, where it will collect a sample of some of the oldest material in the solar system.
Just over a year from now, in October 2018, a year-long survey of the asteroid begins. After a preliminary survey and the transition from star-based navigation to Bennu landmark-based navigation, the detailed survey will begin to determine the spectral, thermal, and geological properties of Bennu. OSIRIS-REx is carrying the Visible and Infrared Spectrometer (OVIRS), which will play a key role in the spectral portion of this survey; this instrument contains an optical linear variable filter (LVF) array made by Viavi Solutions (Milpitas, CA; formerly JDS Uniphase).
OVIRS will measure visible and infrared light from Bennu and is sensitive from blue through near-infrared wavelengths, spanning 0.4 to 4.3 microns. With the help of Viavi's filter, OVIRS will split the light received from Bennu into its component wavelengths to enable identification of different chemicals, each with their unique spectral signatures. OVIRS will provide spectral maps that identify mineral and organic material globally and of candidate sample sites. It will also gather local spectral information of candidate sample sites.
The OVIRS images will help mission scientists choose a sample site. Once the site is chosen, OSIRIS-REx will move to the surface, scoop up a handful of rock and dust, and send the sample capsule toward Earth.
The primary objective of OSIRIS-REx's mission is to return a sample of pristine carbonaceous material from the early Solar System. Scientist believe this material will provide important clues to the origin of life on Earth and the likelihood that life may have originated elsewhere in our solar system.
Source: Viavi Solutions' Optical Security and Performance Products (OSP) business