Catherine Johnson lends expertise to asteroid sampling mission OSIRIS-REx
UBC planetary geophysicist Catherine Johnson is watching today’s launch of NASA's OSIRIS-Rex mission with more than a passing interest.
The Canadian Space Agency’s contribution to the mission is the OSIRIS-Rex Laser Altimeter (OLA), an instrument designed to map the shape of the asteroid Bennu. Johnson is deputy instrument scientist for OLA, assisted by UBC Earth, Ocean and Atmospheric Sciences colleagues Lydia Philpott and Manar Al Asad.
“OLA will map the asteroid shape in unprecedented detail, down to a resolution of a few centimeters,” says Johnson. “This is a first for asteroid studies and will provide insights into the interior structure and origin of the asteroid, as well as help OSIRIS-REx successfully return a sample from the surface.”
Johnson will collaborate with an international science team on OLA, including lead instrument scientist Michael Daly at York University and colleagues at the University of Calgary, Johns Hopkins University Applied Physics Laboratory, Lockheed Martin Space Systems, MacDonald, Dettwiler and Associates, and Optech.
OSIRIS-REx will map and subsequently sample Bennu. The carbonaceous asteroid is leftover material from our protoplanetary disk, the cloud of gas and dust leftover from the Sun’s formation that collapsed to form the Solar System. The asteroid’s material remains relatively untouched since that event 4.5 billion years ago. Scientists intend to use samples of the asteroid to better understand the origins of our Solar System and the chemical precursors to life on Earth.
As it approaches Bennu in August of 2018, it will use a set of precise thrusters to match the asteroid’s orbit around the sun. OSIRIS-REx will map Bennu’s shape, topography and surface features for over a year. OLA collects data by emitting laser pulses and timing how long the light takes to return to its sensors after reflecting off the asteroid’s surfaces.
The topographic information collected by OLA, together with other physical and chemical data collected from OSIRIS-Rex’s four other imaging instruments, will be used to select a location on the asteroid from which to sample material. In a delicate maneuver, OSIRIS-REx will extend an arm to touch the asteroid’s surface, collecting at least 60 g of material in a few seconds of contact. OSIRIX-REx will return home with the sample to Earth in 2023.