Leonard David's INSIDE OUTER SPACE

Recurrent Slope Linae on the Palikir Crater walls on Mars.
Credit: NASA/JPL/University of Arizona

Those perplexing recurring slope lineae (RSL) on Mars might be explored in the future by a Pop-Up Flat Folding Explorer Rover.

The idea was detailed at the recent American Geophysical Union’s Fall Meeting held in San Francisco.

NASA Mars Reconnaissance Orbiter’s HiRISE image of recurring slope lineae in Melas Chasma, Valles Marineris. Arrows point out tops and bottoms of a few lineae.
Credit: NASA/JPL-Caltech/University of Arizona

According to an abstract overview by Kalind Carpenter and his colleagues, definitive confirmation of current liquid water activity on Mars would be a major step in establishing the present day habitability of Mars and the possibility of extant life. RSL’s are one of the most intriguing targets for exploring current water activity on the Red Planet.

Carpenter is a robotics engineer in the Robotic Vehicles and Manipulators Group at the Jet Propulsion Laboratory in Pasadena, California.

Steep slopes

RSL have been identified as seasonally dependent streaks that darken and grow downward on steep slopes.

“Currently, they are best explained as intergranular briny water flows percolating through the top layers of the regolith, but orbital observations cannot provide a definitive confirmation,” Carpenter and his project teammates noted.

Features called recurrent slope lineae (RSL) have been spotted on some Martian slopes in warmer months. Some scientists think RSL could be seasonal flows of salty water. Red arrows point out one 0.75-mile-long (1.2 kilometers) RSL in this image taken by NASA’s Mars Reconnaissance Orbiter.
Credit: NASA/JPL-Caltech/Univ. of Arizona

While the features are indeed intriguing, landing and probing near RSL presents a number of challenges to traditional mission architectures “including stringent planetary protection requirements of a Mars special region mission.”

Spacecraft sterilization

Enter the Pop-Up Flat Folding Explorer Rover (PUFFER).

Mobile Instruments for Mars Exploration includes the Pop-Up Flat Folding Explorer Rover (PUFFER).
Credit: NASA/JPL-Caltech

Two versions were noted at the AGU gathering, devices capable of traversing greater than 50 degree slopes and able to be cleaned to a greater then “log 7 reduction in bioburden” – a spacecraft sterilization standard.

The rover concept would be equipped with the Thermal and Electrical Conductivity Probe and/or a miniature version of the Tunable Laser Spectrometer to characterize RSL and establish habitability.

Having multiple PUFFER agents increases the communication range of the field survey by using individual PUFFERs as repeaters.

Go with the flow

The exploration rover would be able to gauge the permafrost freeze-thaw cycle that drives the underlying RSL processes at sites on Mars and characterize the chemical makeup of the flows.

“This will inform on the period of liquid phase and the available chemicals for biological processes,” according to Carpenter and his colleagues.

Overall, the Mobile Instruments for Mars Exploration (MIME) mission concept addresses fundamental NASA priorities of searching for life and habitable areas in our solar system.

Modern-day habitability?

On Mars, present day habitability is still fundamentally tied to finding liquid water.

NASA Curiosity rover on the Red Planet prowl since August 2012 and assessing the habitability of Mars.
Credit: NASA/JPL-Caltech/MSSS

The currently operating Curiosity rover has provided abundant evidence of Mars habitability 3-4 billion years ago in the active lacustrine system of Gale Crater – the robot’s exploration site.

MIME would pursue evidence for modern day liquid flows, and hence modern day habitability.

“A confirmed detection of liquid activity near the surface of Mars would intensify the already robust debate about the suitability of exploring Mars not only for signatures of past life, but also for signatures of extant life,” Carpenter and colleagues explained at the AGU.