A made-in-Canada laser aboard NASA's OSIRIS-REx spacecraft has produced high-resolution topographic maps of the four locations on asteroid Bennu that mission scientists have identified as candidates for sample collection.
The OSIRIS-REx Laser Altimeter, or OLA, is equipped with two lasers that scanned the asteroid's surface to produce detailed images of the boulders, craters and other geological features at each of the four sites. These maps will be crucial in helping mission scientists select the safest and most scientifically interesting of the approximately 10-metre-wide candidates – known as Nightingale, Kingfisher, Osprey, and Sandpiper.
OLA's high-resolution results follow the activation of the instrument's low-energy laser transmitter (LELT) at the beginning of . The LELT is designed to fire 10,000 light pulses per second at the asteroid, and operates at a range of less than 1 km above Bennu's surface.
In previous mission phases, OLA's high-energy laser transmitter (HELT) – firing 100 pulses per second from greater distances – collected data that enabled the creation of the first 3D lidar map of the asteroid in .
By , OLA's HELT had collected about 9 million additional measurements to complete coverage of the entire asteroid, compiling the first global map of asteroid Bennu's topography.
Mission scientists anticipate that high volumes of data collected by OLA's LELT – in the order of several billion measurements – will enable the creation of a new, higher-resolution global map, featuring one data point per 7 centimetres and offering an unprecedented level of detail over Bennu's entire surface.
High-resolution maps of the four potential sample sites, like that of the Sandpiper site below, will allow OSIRIS-REx scientists to:
- assess the safety and accessibility of each region
- locate landmarks that will help the spacecraft navigate during sample collection
- identify areas of fine-grained material compatible with OSIRIS-REx's sampling device
OLA's LELT will continue to work in tandem with other instruments on the spacecraft to gather crucial data about the surface of the asteroid. A primary and a backup site will be announced in , and the spacecraft is scheduled to begin rehearsing sampling manoeuvres in early .
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