One of the Curiosity rover's main missions is to determine the likelihood that Mars could support life, either now or in the past, and a new instrument developed by NASA's Goddard Space Flight Center could function as "a rover's sense of smell" to aid the search. Using lidar, a light-based sensing system that works like radar, the instrument can detect organic particles that indicate living organisms, and even determine how recently that life may have been present.
Lidar systems operate in the same kind of way as radar, but make their measurements with lasers instead of radio waves. The technology appears in navigation systems for autonomous cars, is being developed by the ESA to study Earth's wind patterns, and is used by the military to remotely detect potentially harmful chemicals, pathogens and toxins in the air. Now Branimir Blagojevic, a technologist at Goddard, has created a prototype that would use fluorescence-based lidar to sniff out signs of life on other planets.
"NASA has never used it before for planetary ground level exploration," says Blagojevic. "If the agency develops it, it will be the first of a kind. If the bio-signatures are there, it could be detected in the dust."
Once on another planet, the device, which the team calls the Bio-Indicator Lidar Instrument (BILI), will search for plumes of dust from its perch atop a mast on a rover. When it finds a viable dust sample, it pulses UV light from two lasers through it and studies the way the particles glow in response. That can alert the scientists back on Earth to the presence of organic particles, their size, and even how recently they may have been created.
Branimir Blagojevic, the developer of the BILI prototype, in front of a screen showing the device's user interface
Equipped with lidar, a rover could perform these analyses from a few hundred meters away with great precision and speed, allowing it to study normally inaccessible areas and do so without contaminating the samples. Like the CO2 Sounder Lidar, which would measure levels of CO2 in Earth's atmosphere from space, the instrument could also be attached to a spacecraft to conduct the search from orbit.
"This makes our instrument an excellent complementary organic-detection instrument, which we could use in tandem with more sensitive, point sensor-type mass spectrometers that can only measure a small amount of material at once," says Blagojevic. "BILI's measurements do not require consumables other than electrical power and can be conducted quickly over a broad area. This is a survey instrument, with a nose for certain molecules."
Before it's ready for takeoff, the team is testing the range of organic molecules that BILI can detect and at what concentrations, as well as ensuring the device is as durable and compact as possible.
"We are ready to integrate and test this novel instrument, which would be capable of detecting a number organic bio-signatures," says Blagojevic. "Our goal is increasing the likelihood of their discovery."