The technology that will guide NASA's Mars 2020 mission to a landing on the surface of Mars began testing recently in the skies over Death Valley in California. Installed in an Airbus helicopter, an engineering prototype of the Lander Vision System (LVS) was put through a series of pre-planned maneuvers designed to test the device's ability to collect and analyze images of the mountainous desert landscape for landing navigation purposes.
Landing on another planet is a dangerous operation with a notoriously high failure rate. One reason for this is that, up until now, every unmanned planetary landing has been made blind. Though modern spacecraft are capable of some impressive autonomous functions, they have no way beyond crude radar to sense where they are landing.
Instead, every landing is based on pre-loaded navigation instructions that put the lander down inside an elliptical area that has been selected for flatness and lack of craters, boulders, and crevices. Essentially, a robotic planetary landing is a matter of starting descent and keeping fingers crossed.
The LVS, as part of the Terrain-Relative Navigation (TRN) guidance system, will steer the Mars 2020 spacecraft to a landing on the Red Planet at Jezero Crater in the Syrtis Major region on February 18, 2021. The LVS is an integrated, bolt-on sensor package that provides the onboard computer with a continuous stream of data on terrain relative position, velocity, attitude and altitude. Made from off-the-shelf components, it does this by means of a camera for feature tracking and velocity estimation, while a dual-use flash lidar looks for surface hazards.
The idea is that the LVS helps the lander build up a terrain map during descent so the computer can select a safe landing site. It can not only zero in on a particular site, but also, if fuel is low, select from other relatively safe sites within the lander's flight range.
This is not only to improve the odds of a safe landing, but to also allow mission planners to make the mission more successful from a scientific point of view. The kind of places that scientists would like to visit are often too far from a conventional landing site for a rover to get to. With the help of the LVS and the TRN system, the hope is that Mars 2020 will be able to land in more hazardous areas with a much smaller ellipse footprint.
Mars 2020 is scheduled to lift off from Cape Canaveral Air Force Station sometime in July of next year.
Source: NASA