NASA's Mars Reconnaissance Orbiter (MRO) is being taught a new "roll" maneuver to enhance its ability to detect water on the Red Planet. After almost 20 years in operation, engineers are getting more out of the spacecraft by having it essentially turn nearly upside down.
This new maneuver, which involves rolls of up to 120 degrees (compared to its original design for 30-degree rolls), significantly improves the performance of MRO's Shallow Radar (SHARAD) instrument. By rolling the spacecraft, SHARAD gets a clearer, more direct line of sight to the Martian surface, strengthening the radar signal by 10 times or more. This allows it to peer deeper underground, from about 0.8 to 2 kilometers (half a mile to just over a mile), and better distinguish between materials like rock, sand, and ice, specifically searching for liquid and frozen water.
These "very large rolls" are carefully planned, as they temporarily disrupt communication with Earth and the ability of the solar arrays to track the Sun. However, the potential payoff is significant: gaining a clearer picture of the Martian underground for future astronaut missions, where ice could be vital for producing rocket propellant and drinking water.
Recent findings related to water on Mars, supported by missions like MRO and InSight, indicate:
Subsurface liquid water: Seismic data from the InSight lander has hinted at a vast reservoir of liquid water deep beneath the Martian surface, possibly an aquifer layer between 5.4 and 8 kilometers down, which could hold enough water to cover the entire planet in an ocean hundreds of meters deep.
Recurring slope lineae (RSL): MRO previously provided strong evidence in 2015 for intermittent flows of briny liquid water on present-day Mars, observed as dark streaks on slopes during warmer seasons. These were attributed to hydrated salts like perchlorates. While some subsequent studies have debated if these are solely water-driven, the initial findings from MRO were significant.
Ancient water evidence: MRO has also contributed to mapping chloride salts, indicating that surface water may have left salt minerals behind as recently as 2 to 2.5 billion years ago, extending the timeline of liquid water on Mars.