The CADRE rovers have completed construction and testing, and together they will map the lunar surface as a technical demonstration to demonstrate the possibilities for multi-robot missions. Three small rovers, which will explore the moon in synchrony with each other, are approaching launch. Engineers at NASA’s Jet Propulsion Laboratory in Southern California recently completed assembling the robots and then subjected them to a series of grueling tests to ensure they would survive arduous rocket rides into space and travel through the unforgiving lunar environment.

Part of a technology demonstration called CADRE (Cooperative Autonomous Distributed Robotic Research), each solar-powered rover is about the size of a carry-on suitcase. The rovers and associated equipment will be installed on a lander bound for the Rainier Gamma region of the moon. They will spend the daylight hours of a lunar day (equivalent to about 14 days on Earth), conduct experiments, independently explore, map, and use ground-penetrating radars to scan beneath the lunar surface.

The goal is to demonstrate that a group of robotic spacecraft can work together as a team to perform tasks and record data without receiving explicit commands from mission controllers on Earth. If the project is successful, future missions could include teams of robots deployed for simultaneous distributed science measurements, potentially to support astronauts.

Engineers spent many hours testing the rovers and resolving errors to finalize the hardware, test it, and prepare it for integration with the lander.

“We have been very active in preparing this technical demonstration for the lunar adventure,” said Subha Komandur, JPL CADRE project manager. “It has been tested and sometimes retested almost around the clock for months, but the team’s hard work is paying off. “We now know that these rovers are ready to show what a team of small space robots can achieve together.”

While the list of tests is extensive, among the most challenging are extreme environmental conditions to ensure the rovers can withstand the challenging road ahead. This includes being in a thermal vacuum chamber that simulates the airless conditions and extreme high and low temperatures of space. The hardware is also attached to a special “shaker tray” that vibrates intensely to ensure it can survive the journey outside Earth’s atmosphere.

“We subject our rovers to this: ‘shaking’ to simulate a rocket launch and ‘baking’ to simulate the extreme temperatures of space.” “It’s very frustrating to watch in person,” said Guy Zohar, flight system project manager at JPL. “There’s a lot of cherry-picking in our project. We use commercial parts. We expect these to work, but we always get a little nervous when we start testing. “Fortunately, every test was ultimately successful.”

Engineers also conducted environmental tests on three pieces of hardware installed on the lander: a base station with which the rovers will communicate via network radios, a camera that will provide an overview of the rovers’ activities, and delivery systems that will bring the rovers down. the lunar surface via a fiber cable slowly fed from a motorized reel.

Meanwhile, engineers working on CADRE’s collaborative autonomy software spent many days at JPL’s rocky, sandy Mars shipyard with full-scale versions of the rovers, called development models. These test rovers with flight software and autonomous capabilities demonstrated that they could achieve key project goals.

They rode together in formation. When they encountered unexpected obstacles, they changed plans as a group, shared updated maps, and replanned agreed-upon routes. And when one rover’s battery ran low, the entire team paused to continue together later.

The project conducted several trips at night under large floodlights so that rovers could experience extreme shadows and lighting similar to what they would encounter during a lunar day. The team then conducted similar test runs with flight models (moon rovers) in the JPL clean room. Things got out of hand when the perfect ground turned out to be a little slippery (a different texture than the lunar surface). But they stopped, adapted and went the way they planned.

“Working with curveballs is important for autonomy. What’s important is that robots react to things that don’t go according to plan and then replan and still succeed,” said JPL’s Jean-Pierre de la Croix, CADRE’s principal investigator and head of autonomy. “We are entering a unique environment on the Moon, and of course there will be some unknowns. We have done our best to prepare for them by testing software and hardware together in different situations.”

The hardware will then be delivered to Intuitive Machines for installation on NASA’s Nova-C lander, which will launch atop a SpaceX Falcon 9 rocket from the Kennedy Space Center in Florida.