Mastcam-Z sees details of Martian dust dynamics

01 Feb 2023

Video camera records movement of dust blown up by Ingenuity helicopter.

The first "real world" study of how Martian dust is lifted from the surface of the planet by moving air currents has been carried out by Stevens Institute of Technology, the Space Science Institute, and JPL.

Martian atmospheric dust is known to be a major driver of planetary weather, but how the dust gets carried from the surface into the air has not been extensively studied, with much uncertainty remaining about minimum wind stress and the exact types of sand particles involved.

The new data came from an experiment combining two elements of the Perseverance Mars rover, in which the Mastcam-Z camera carried on the rover filmed dust raised by the rotors of Ingenuity, the small robotic helicopter that travelled to Mars as part of the same mission.

As reported in Journal of Geophysical Research: Planets, the images captured by Mastcam-Z will help increase understanding of how Martian dust is mobilized from the surface into the air, currently the least understood aspect of the global distribution of atmospheric dust on Mars.

The findings could also assist NASA's Mars Sample Return Program, which will ultimately retrieve samples collected by Perseverance, or the Dragonfly mission that will head for Saturn's moon Titan in 2027.

Mastcam-Z includes two zoom cameras mounted on Perseverance's remote sensing mast, and is an evolution of the camera instruments on board Curiosity, the previous Mars rover. The cameras each include a digital 1600 x 1200 pixel CCD sensor, an 8-position filter wheel, a zoom assembly and single-lens focusing assembly.

The instrument was commissioned in 2014 from Arizona State University. "These cameras will be the main eyes of NASA's next rover," commented ASU's Jim Bell at the time. "This matched pair of zoom cameras will each provide broad-band red/green/blue (RGB) color imaging, as well as narrow-band visible to short-wave near-infrared multispectral capability."

Mastcam-Z opens up a new line of research

Mastcam-Z recorded video from six flights of Ingenuity, imaging the dust that lifted from the surface during the helicopter's ascents, traverses and descents. Image processing of the low-resolution videos captured by Perseverance allowed the project to identify tiny variations between video frames and monitor the light intensity of individual pixels, from which the size and total mass of the dust clouds could be calculated.

"It was exciting to see the Mastcam-Z video from Perseverance, which was taken for engineering reasons, end up showing Ingenuity lifting so much dust from the surface that it opened a new line of research," said Mark Lemmon from the Space Science Institute.

The data indicated that Ingenuity kicked up about a thousandth of its own mass in dust each time it flew, many times more dust than would be generated by an equivalent helicopter on Earth, although the project noted that direct comparisons are tricky.

A greater understanding of dust movement could indicate ways to keep solar panels operational for longer on Mars, or give new insights into the role of wind and wind-carried dust in weather patterns and erosion on the planet or elsewhere.

"When you think about dust on Mars, you have to consider not just the lower gravity, but also the effects of air pressure, temperature, air density - there's a lot we don't yet fully understand," said Jason Rabinovitch from Stevens Institute of Technology. "That's what makes studying Ingenuity's dust clouds so exciting."