Science

Audi's Rover on a Mission to the Moon

The automaker is building a Lunar Quattro in aluminium using a 3D process.
15 February, 2017
Audi's latest project is to build a moon rover good enough to win the Google Lunar XPRIZE competition.
Thanks to a sophisticated additive manufacturing process, they're well on their way.

The rules for the rover are straightforward but challenging. The rover has to successfully complete the 384,000-kilometer journey and land safely on the moon. Once there, the unit needs to complete at least a 500-meter drive on the surface, and send HD images back to earth that deliver new, never-seen views.
The first successful team – a definition that also includes proving that 90 percent of the moon mission funding came from private sources – will win the grand prize of $20 million.

There's another catch: They also have to launch before the end of 2017.

That means the clock is ticking for Audi, which is working in partnership with Part-Time Scientists. "For us it's about high engineering ingenuity, not the prize money," says Robert Böhme, the organization's team leader. At Part-Time Scientists, it's about being visionary more than doing the commercial work.
Fortunately, that vision is becoming a reality. The Audi Lunar Quattro rover has been fully developed with a plan to set off in late 2017 on a launch with Spaceflight Inc.

The wheels of the lightweight rover are made entirely with an aluminium alloy powder that is making room for science by cutting back on weight. The XPrize team calculated that a kilogram of payload on the rover is worth €800,000 and the weight savings on four wheels is 1.6 kilograms.

That means the team can load an additional €1.28 million in scientific equipment on board – adding to the scientific value of this moon shot.
The original design called for open-spoke wheels used in the Part-Time Scientist's Asimov Rover, but Audi engineers decided to make the wheels solid to better protect them in the lunar environment and bigger to help them navigate the surface with a four-wheel drive system. Driving speed will be about 3.5 km/h.

That's made possible by using the tiniest of 0.05-millimeter layers of the aluminum-silicon-magnesium-strontium (AlSi10MgSr) powder, processed with a 400-watt diode laser that works in 30-second exposure intervals. All told, it takes 32 hours and 20 minutes to make one of the Quattro Rover wheels.
"3D printing with aluminium makes it possible to produce lightweight parts of almost any shape with a closed shell," said Harald Eibisch, an Audi engineer in casting and 3D development. "The material has also been thoroughly tested in the Audi laboratories. We've been using alloy AlSi10MgSr in the aluminium castings of our Spaceframe bodies for decades."

The Audi Quattro Rover also benefits from the engineering improvements on the suspension system, the vehicle's swing arms, and the camera head. The imaging system on the vehicle includes four cameras that take photos in 360-degree views.
While the design team has been focused on the Lunar Quattro and its test drives here on earth, the Audi engineers aren't stopping there. They're also looking at how to design manned lunar modules in hopes of taking the mission to the next level, and those ideas include designer Sven Vollhardt's two-mode rover.

It allows an astronaut to take samples on a planet without leaving the protective interior of the rover, and relies on a biomimicry design approach that allows it to move like a lizard and "nibble" up samples from the surface. Another design, created by Ramon Sellers-Sirvent, is itself a next generation Quattro, which can rotate 360 degrees and move its wheels like arms.
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