Japan is pitching the rover, and Toyota hopes for a decision from the international consortium on whether to use its proposal by year's end, Sato said. Part of the competition might be various rover concepts floated by NASA, but the U.S. agency has signaled its interest in collaborating with the Japanese.
The rover's mission is to roam the polar regions in search of large deposits of water, in either liquid or solid form. The plan calls for leaving the rover on the moon for five years. Each year, the rover will search a different location for about six weeks.
Its fuel — hydrogen and oxygen — will be dropped off in tanks until the rover finds sufficient H20 on the surface. Then it can make its own fuel through electrolysis. Fuel cells have been a go-to technology for space missions from the 1960s Gemini project through Apollo and the space shuttles. In human-operated craft, the heat and water emissions can be used to help keep the crew alive.
Lunar travel brings challenges completely alien to Toyota's engineering team.
The vehicles have to endure radiation that could fry sensors, extreme heat that would bake plastic or rubber components and fast-flying space debris that could puncture the airtight cabin.
"We must protect against all that," Sato said. "It's like making a bulletproof vest for the vehicle."
The moon is a hard place to drive. It has a dusty, rocky surface that can demand as much as 10 times the energy needed to traverse Earth, and the craters have slopes as steep as 20 degrees.
The Lunar Cruiser must also be self-driving to provide rest and work time for the astronauts. This presents its own challenges in a moonscape lacking roads or high-definition maps.
And most importantly, it must not break down.