Long before the Mars Rover Curiosity landed on August 6, 2012, scientists at NASA were hard at work designing and building prototypes of the next Mars rovers, ones that will accommodate human astronauts exploring the surface of the Red Planet away from a base station for several days at a time.
The original mars landing vehicles, the Viking 1 and Viking 2 landers, arrived 36 years earlier, in 1976. After landing stationary vehicles that could send back information about Mars, NASA landed several roving vehicles: The Pathfinder mission’s Sojurner rover in 1996 and the twin Spirit and Opportunity rovers in 2003.
Each successive mission added new capabilities based on the experiences of the previous ones. The vehicles must be tough enough to survive the intense vibrations of takeoff from Earth, as well as blazing heat during landing on Mars.
Video: Next Mars rover made with 3-D printed parts
Once they arrive, the vehicles will be exposed to dust storms and extreme temperature swings. In addition, rovers must be able to travel long distances over the rough, rocky terrain while cradling and protecting sensitive scientific instruments, and in the future, human astronauts.
The two prototypes, being developed in the Arizona desert, are called the Desert RATS (Research and Technology Studies). The RATS are about the size of a Hummer, and they have pressurized cabins where humans can live for a few days.
In order to design these highly specialized vehicles, NASA is relying on the process of 3-dimensional printing.
Benefits of 3-D printing
3-D printing has been around for 25 years, but its benefits are only recently being exploited. 3-D printing allows engineers to create designs on a computer, and then quickly “print out” a new part, which can be tested, modified, and redesigned as needed.
3-D printers look similar to an oversized coffee maker, and can be used right in an office or laboratory. Several companies make 3-D printers, and they can print parts out of metals or plastics.
For the two prototype Mars Rovers, NASA designers are printing parts out of ABS plastic, PCABS and polycarbonate materials. About 70 complex parts on the rover prototype were built using additive manufacturing, another name for 3-D printing.
How 3-D printing works
Once a piece is designed with the help of a computer, software on the 3-D printer “slices” the design into 2-dimensional layers. These layers will be traced out on the bed of the printer with heated, liquefied plastic, similar to the way an ink jet printer prints out an image on paper.
By building up hundreds of layers of the thin plastic, which fuse together as they cool, a 3-dimensional product.is created.
The printer software also adds support structures that prop up the product as it is being printed. These supports can be broken off easily after the plastic hardens. Once dried, the plastic parts can be sanded, drilled, painted or electro-plated.
The NASA scientists are using a Stratsys 3-D printer to create custom parts, such as flame-retardant vents, camera mounts, a bumper, and pod doors.
Saving taxpayers money
By using 3-D printing, the design process goes much faster, and is much cheaper, than waiting for a machine shop to create each new version of a piece. With a 3-D printer, a new piece can be built within a few hours, rather than days.
Although the (test) rovers used on a desert in Arizona are fitted with 3-D printed parts, the actual rover that takes off for Mars in the future will be made of far more expensive, custom manufactured space-hardened materials.
But by the time those parts are made, NASA—and the American taxpayers who support NASA—will have saved a bundle of time and money in the design process.
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