Over the next couple years, new rovers will explore more of the moon’s surface than ever before. Through its Artemis program, NASA plans to send humans to the moon for the first time in five decades, setting the groundwork for the construction of a permanent lunar base camp. But before any astronauts set foot on the moon, a multinational array of robots will be taking their first steps—or first rolls—across the lunar soil.
In the early 1970s, both the United States and the Soviet Union sent rovers to the moon, but since then, only two new rovers have successfully explored the lunar surface. The Chinese rover Yutu landed in 2013, followed by Yutu-2 in 2019, which is still on the moon today.
Terry Fong, a roboticist at NASA’s Ames Research Center, says lunar rovers in this new wave vary substantially both in size and in technical capabilities, in part because they are each exploring a different part of the satellite. Each rover has unique abilities to match the disparate challenges it will face at its lunar destination. “The environment on the moon is very different depending on where you go,” he adds.
Many of the missions will focus on the lunar soil, or regolith. Some rovers will mark the first attempts of their respective countries to explore the moon. With more than a dozen rover missions planned for the next three years, we sifted through the projects and polled experts to share with you details about five of the most compelling.
This golf-cart-sized rover will seek out underground ice
A key component of NASA’s Artemis program is the Volatiles Investigating Polar Exploration Rover, better known as VIPER. This eight-foot-tall rover will spend 100 Earth days exploring the moon’s South Pole in 2024 in order to study the water found under the lunar surface.
VIPER will help scientists determine how polar water is distributed and whether or not it could be used by future crewed explorations. To carry out this mission, the rover will carry several scientific instruments, including a regolith and ice drill and multiple spectrometers that can detect hydrogen atoms from water.
Parts of the poles are perpetually shadowed, making them the moon’s coldest spots; temperatures can dip below minus 400 degrees Fahrenheit. VIPER will have to survive temperatures that reach 500 degrees Fahrenheit higher in the sunlight. VIPER will also travel over challenging surface textures and obstacles, a potential disturbance for all its sensitive scientific equipment. The rover’s wheels rotate in all directions, giving it the ability to smoothly drive sideways, diagonally or spin in circles. Each wheel can also lift upward independently to extract itself from sandy soils.
VIPER’s movements will be controlled continuously by human engineers back on Earth due to the relatively short distance between the moon and Earth. In contrast to Mars rovers, for which commands and data are generally exchanged only once per day, VIPER’s drivers will direct the rover in real time. As Fong says, VIPER is “going to be operated in a way that's radically different from past NASA rover missions.”
A “beehive” will launch miniscule robots to study lunar dust
While most lunar rovers follow the standard car-like design, Colmena, the first Mexican space mission to land on the moon, breaks out of that box. Colmena, or “beehive” in Spanish, is a small catapult connected to a cylindrical container that houses five tiny autonomous robots. After landing on the moon, the container’s lid will open, and the catapult will launch its robotic worker bees 30 feet across the lunar landscape. The bite-size rovers, less than an inch tall and each weighing next to two ounces, are shaped like flattened rings encircling two wheels and a solar panel. After being shot out onto the surface, the rovers will test out their ability to navigate and group together autonomously, then carry out their main scientific mission of studying the lunar surface.
Colmena was built by the Laboratory for Space Instrumentation at the Universidad Nacional Autónoma de México (National Autonomous University of Mexico) and will travel to the moon’s Lacus Mortis, or “Lake of Death,” later this year aboard a lunar lander made by U.S.-based space company Astrobotic.
Colmena’s tiny rovers will traverse a fluid-like layer of fluffy, floating dust rather than driving over a compact surface as bigger rovers do, which will enable them to study the properties of that electrostatically charged bits. They will measure particle size and magnetic fluctuations just above the lunar surface where that floating dust mixes with plasma from solar winds. The rovers’ findings will help scientists prepare for future exploration involving miniaturized robots.
A dynamic duo will help demystify the magnetic secrets of the lunar swirls
Scientists have proposed multiple explanations for lunar swirls, and David Blewett, principal investigator of the Lunar Vertex project, hopes that the data they collect can help determine which is correct. “There are several hypotheses for how they formed, and they all make predictions about the texture and particle size of the surface,” says Blewett.
The rover is outfitted with a multispectral microscope to take measurements of the regolith. Based on the particles’ coarseness, brightness and other characteristics, scientists can narrow down which lunar swirl origin story is most likely to be true.
The lander and rover also have instruments to measure the magnetic fields of the lunar swirls. “The moon today doesn't have a global magnetic field, the way the Earth does,” explains Blewett, but some regions, such as the lunar swirls, are magnetized. This mission will provide the first on-the-ground investigation of these magnetic anomalies. The data collected could help uncover the source of the anomalies and explain why they co-occur with lunar swirls.
The Lunar Vertex will have just 13 Earth days, the time between lunar sunrise and sunset, to travel around Reiner Gamma and collect as much data as possible. If all goes well, this little rover will help us to understand one of the most beautiful and enigmatic features of the moon.
A transformable rover may pave the way for a crewed lunar vehicle
Lunar landers and rockets have only so much space for all the possible missions, so a major priority for scientists has been to make small and lightweight rovers that can move around and collect data efficiently. The Japan Aerospace Exploration Agency (JAXA) has excelled at this rover miniaturization game. In collaboration with Doshisha University as well as Sony and the toy company Tomy, JAXA developed a tiny rover that weighs just over half a pound and has the ability to transform into different shapes. “The transforming mechanism and technology that Japanese toy manufacturer used in transformable toys are incorporated into our lunar robot,” writes a JAXA representative by email, “which makes it compact when transporting to the lunar surface.”
During the flight to the moon, the small rover will remain in a roughly spherical shape, measuring only three inches in diameter. But once it gets deposited onto the lunar surface, it will split apart horizontally, changing shape to reveal central cameras flanked by two sturdy wheels and a tail. In this expanded state, the rover can move about on the soft and uneven terrain of the lunar surface.
JAXA’s rover will be delivered to the moon later this year by a lunar lander created by Japanese space company ispace. Its goals are to photograph the lunar surface as it responds to disturbance and test out a navigation system. The data will help JAXA optimize the designs for the much larger rover it’s working on next: the Lunar Cruiser. The result of a collaboration between JAXA and Toyota, the Lunar Cruiser will be a fully pressurized vehicle that might carry astronauts thousands of miles across the surface of the moon.
These rovers will work as a team to carry out missions on their own
Engineers at NASA’s Jet Propulsion Laboratory (JPL) are designing teams of rovers that work together to explore both above and below the surface of the moon. Called Cooperative Autonomous Distributed Robotic Explorers, or CADRE, these shoebox-sized rovers are experts at coordinating their actions to carry out a task, with minimal human supervision required.
Four CADRE rovers will be delivered to the moon in 2024 aboard a lunar lander from American space company Intuitive Machines. They will use their teamwork skills, along with ground-penetrating radar technology, to create a 3-D map of the subsurface. Creating this map will require the rovers to move in sync with each other, taking measurements simultaneously from various different locations.
Subha Comandur, the CADRE project lead at JPL, explains that all the engineers need to do is tell the rover team what region to explore, and the machines take it from there. They even pick their own leader to direct the mission. “The leader then decides the path and communicates that to the individual agents,” she says.
According to Comandur, the rovers can work together in teams of any size and flexibly adjust to losing a teammate mid-mission, enabling them to carry out dangerous or risky jobs. “A rover could succumb to the lunar environment, and the remaining team will adapt,” she says.
The rovers are expected to prove useful far beyond the moon as well. “There’s already plans for infusing this technology onto the next Mars mission,” says Comandur. And she suggests that CADRE could one day explore the moons of Jupiter as well.