MARLI and Mars: Measuring Martian Winds

NASA scientists adapt technologies to produce its first planetary wind LIDAR.

Scientists, cartoonists, authors, filmmakers, elementary kids, hobbyists, a random average Joe (or Jane) … Time and time again, this seemingly random list of earthlings has shown a shared fascination with its closest neighbor: Mars.

Whether a 19th-century story about Martians referenced as a cartoon character’s home planet, a research project by a kid or the next Hollywood blockbuster, Mars continues to enthrall the masses. Luckily those masses include some of the brightest minds that just happen to work for NASA.

Since its first successful attempt to explore the planet in 1969 with the launch of orbiters Mariner 6 and 7, NASA has helped the human understanding of Mars grow exponentially. Orbiters have provided weather satellite communications and extensive geographical data. New technologies resulted in successful craft landings with rovers that provided previously unattainable geophysical mapping and soil samples.

But like any nosey neighbor, now that we’ve met, our interest has only been piqued. Thanks to information from a recent press release, understanding our neighbor’s quirks will soon become firsthand information. Adaptation of recently developed technologies has provided scientists the ability to develop the experimental MARLI, short for MARs Lidar. It would provide details on the winds of Mars—secret information our neighbor has yet to provide—which have been measured at 45 miles per hour or faster and often create a cloud that covers the planet in dust.

MARLI instrument breadboard and optical etalon. (Image courtesy of NASA.)

MARLI instrument breadboard and optical etalon. (Image courtesy of NASA.)

“After 20-plus years of launching orbiters and rovers, we’ve learned a lot about environmental conditions on Mars, including temperatures and atmospheric gases,” said Mike Smith, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md. “If we were going to write a list of the things we don’t know about, winds would top the list.”

Scientists hope that MARLI will mature into a future orbiter mission and serve as NASA’s first interplanetary wind light detection and radar (Lidar)—a remote-sensing method that uses light to analyze particle composition in the atmosphere. MARLI would be used to profile the vertical distribution of dust and ice particles and measure the wind velocities to monitor conditions in different locations and seasons, which could help determine the best landing spots.

Once in orbit, MARLI would point its beam approximately 30 degrees directly below the craft. This would allow it to act similarly to a Doppler radar. Instead of measuring velocity, like radar, MARLI would continuously pulse infrared light on the surface with its laser. Dust and ice particles would create some light scatter before reaching the surface, but some of that light would make its way back to an onboard telescope that gathers returning backscatter signals and directs them to detectors. The result: true measurements of wind speed and distribution of dust and ice in the atmosphere of that location.

“Our approach has a high likelihood of success,” Smith said. “It leverages key laser and receiver technologies from previous space lidar missions and other developments. The hardest part is getting a ride to Mars.”

While we still have a few years before scientists get MARLI road ready, it’s good to know that us nosey neighbors will soon get to know our neighbor even better. To learn more about LIDAR and space exploration, check out “Can LIDAR Find Life on Mars?