The CADRE rovers have finished testing and construction. They will survey the lunar surface collectively as a technology demonstration to highlight the potential of multirobot missions.

Three tiny rovers that will travel around the Moon simultaneously are almost ready to take off. After completing the robots’ assembly, engineers at NASA’s Jet Propulsion Laboratory in Southern California put them through a rigorous battery of tests to make sure they would withstand both their jarring rocket launch into space and their treks across the harsh lunar environment.

Each solar-powered rover, which is a component of the CADRE (Cooperative Autonomous Distributed Robotic Exploration) technological demonstration, is roughly the size of a carry-on suitcase. A lander destined for the Moon’s Reiner Gamma region will be equipped with the rovers and related hardware. During a lunar day, which is equal to around 14 days on Earth, they will carry out experiments by autonomously exploring, mapping, and piercing the Moon’s surface with ground-penetrating radar.

The idea is to demonstrate that a collection of robotic spacecraft can function as a unit to complete tasks and gather data without direct orders from mission controllers on Earth. Should the study be successful, robot teams may deploy on future flights to gather scattered scientific measurements in real time, possibly to assist astronauts.

To complete the hardware, get it through testing, and make it ready for integration with the lander, engineers have put in a lot of overtime testing rovers and fixing issues.

“We have been in overdrive getting this tech demo ready for its lunar adventure,” said Subha Comandur, CADRE project manager at JPL. “It’s been months of nearly round-the-clock testing and sometimes re-testing, but the team’s hard work is paying off. Now we know these rovers are ready to show what a team of little space robots can accomplish together.”

Bake and Shake

Although there are many tests on the list, the most difficult ones include harsh environmental settings to make sure the rovers can survive the rigors of the journey ahead. This involves being imprisoned in a thermal vacuum chamber designed to replicate the airless environment and intense heat and cold of space. Additionally, the gear is fastened to a unique “shaker table” that vibrates violently to ensure that it will withstand the trip outside of Earth’s atmosphere.

“This is what we submit our rovers to: ‘shake’ to simulate the rocket launch itself and ‘bake’ to simulate the extreme temperatures of space. It’s very nerve-wracking to witness in person,” said JPL’s Guy Zohar, the project’s flight system manager. “We’re using many carefully selected commercial parts on our project. We expect them to work, but we’re always a little worried when we go into testing. Happily, each test has ultimately been successful.”

Three hardware components that are mounted on the lander were also subjected to environmental testing by engineers: a camera that will record the rovers’ activities, a base station that the rovers will communicate with through mesh network radios, and the deployer systems that will slowly feed a fiber tether from a motorized spool to lower the rovers to the lunar surface.

Testing Code Additionally

Meanwhile, development models—full-scale replicas of the rovers—have been in JPL’s rocky, sandy Mars Yard for many days, housing engineers working on CADRE’s cooperative autonomous software. These test rovers demonstrated their ability to achieve important project objectives by demonstrating their autonomy and flying software aboard. They formed a convoy while driving together. When unanticipated challenges arose, they collaborated to reorganize coordinated routes and exchanged updated maps. Additionally, the crew waited when the battery on one rover ran low so that they might continue together later.

In order to provide the rovers with harsh shadows and lighting that closely resembled what they would experience during the lunar day, the group conducted multiple nighttime drives under massive flood lamps.

Subsequently, the scientists used flight models—the rovers that will travel to the Moon—in a JPL clean room to conduct comparable driving testing. The robots broke formation when the clean floor there turned out to be a little slick—a texture distinct from the lunar surface. However, they came to a halt, made the necessary adjustments, and resumed their intended course.

“Dealing with curveballs – that’s important for the autonomy. The key is the robots respond to things going off plan, then they replan and are still successful,” said JPL’s Jean-Pierre de la Croix, CADRE principal investigator and autonomy lead. “We’re going to a unique environment on the Moon, and there will, of course, be some unknowns. We’ve done our best to prepare for those by testing software and hardware together in various situations.”

Subsequently, the hardware will be shipped to Intuitive Machines to be installed on a Nova-C lander, which is scheduled to fly from NASA’s Kennedy Space Center in Florida atop a SpaceX Falcon 9 rocket.

Additional Information About the Project

JPL, a branch of Caltech located in Pasadena, California, oversees the CADRE technology demonstration project for NASA’s Space Technology Mission Directorate in Washington, D.C., as part of the Game Changing Development initiative. NASA’s Science Mission Directorate oversees the CLPS (Commercial Lunar Payload Services) program, which includes the payload CADRE. The project was funded by the agency’s Ames Research Center in Silicon Valley, California, and Glenn Research Center in Cleveland, Ohio. At the company’s Pasadena location, Motiv Space Systems created and manufactured essential hardware components. Research from South Carolina’s Clemson University was used to support the proposal.