Rolling for science: Mars orbiter learns new moves after nearly 20 years in space
by Andrew Good, Karen Fox, Molly Wasser, NASA
edited by Stephanie Baum, reviewed by Andrew Zinin
After nearly 20 years of operations, NASA's Mars Reconnaissance Orbiter (MRO) is on a roll, performing a new maneuver to squeeze even more science out of the busy spacecraft as it circles the Red Planet. Engineers have essentially taught the probe to roll over so that it's nearly upside down. Doing so enables MRO to look deeper underground as it searches for liquid and frozen water, among other things.
"Not only can you teach an old spacecraft new tricks, you can open up entirely new regions of the subsurface to explore by doing so," said Gareth Morgan of the Planetary Science Institute.
The orbiter was originally designed to roll up to 30 degrees in any direction so that it can point its instruments at surface targets, including potential landing sites, impact craters, and more.
We're unique in that the entire spacecraft and its software are designed to let us roll all the time," said Reid Thomas, MRO's project manager at NASA's Jet Propulsion Laboratory.
The process for rolling isn't simple. The spacecraft carries five operating science instruments that have different pointing requirements. To target a precise spot on the surface with one instrument, the orbiter has to roll a particular way, which means the other instruments may have a less-favorable view of Mars during the maneuver.
| Instrument | Type | Function |
|---|---|---|
| SHARAD | Radar | Peering below the Martian surface |
| HiRISE | Camera | High-resolution imaging |
| MARSIS | Radar | Detecting subsurface materials |
That's why each regular roll is planned weeks in advance, with instrument teams negotiating who conducts science and when. Then, an algorithm checks MRO's position above Mars and automatically commands the orbiter to roll so the appropriate instrument points at the correct spot on the surface. At the same time, the algorithm commands the spacecraft's solar arrays to rotate and track the sun.
Very large rolls, which are 120 degrees, require even more planning to maintain the safety of the spacecraft. The payoff is that the new maneuver enables SHARAD to have a deeper view of Mars than ever before.
Significance of SHARAD
Designed to peer from about half a mile to a little over a mile (1 to 2 kilometers) below ground, SHARAD allows scientists to distinguish between materials like rock, sand, and ice. The radar was especially useful in determining where ice could be found close enough to the surface that future astronauts might one day be able to access it. Ice will be key for producing rocket propellant for the trip home and is important for learning more about the climate, geology, and potential for life on Mars.
In 2023, the team decided to try developing 120-degree very large rolls to provide the radio waves an unobstructed path to the surface. What they found is that the maneuver can strengthen the radar signal by 10 times or more, offering a much clearer picture of the Martian underground.
Challenges of Large Rolls
While SHARAD scientists are benefiting from these new moves, very large rolls face operational challenges. The large roll is so extensive that the spacecraft's communications antenna isn’t pointed at Earth, and its solar arrays can't track the sun. "The very large rolls require a special analysis to make sure we'll have enough power in our batteries to safely do the roll," Thomas said.
Given the time involved, the mission limits itself to one or two very large rolls a year. But engineers hope to streamline the process for more frequent use.
Conclusion
In summary, NASA's Mars Reconnaissance Orbiter's ability to perform special rolling maneuvers not only allows for advancements in Martian research but also demonstrates the continued adaptability and longevity of space missions. The findings from these new capabilities continue to enhance our understanding of Mars's geology and potential for future exploration.
For More Information
For a more in-depth understanding of the technology and its implications, refer to the following:
This article is based on data provided by NASA and peer-reviewed studies conducted in the domain of planetary science.
