We're still several years away from a Mars Sample Return Mission. So, for now, we'll have to settle for the next best thing. NASA's Jet Propulsion Laboratory has created a true-size facsimile of "Block Island"— a Martian meteorite discovered by the Opportunity rover in 2009.
Usually, meteorites break apart upon hitting the Martian surface, since the atmosphere is too thin to slow them down. Scientists believe Block Island remained intact due to the combination of a very specific entry point into the atmosphere and a very shallow flight path.
Whatever the reason, this is the largest meteorite yet found on Mars: at two-feet wide and comprised of iron and nickel, it is estimated to weigh about a half-ton.
Block Island's plastic doppelgänger here on Earth is considerably lighter, but the resemblance is startling. Scientists based the design on detailed measurements and stereo images taken by Opportunity's panoramic camera. Still, the rover was not able to see every square inch of the meteorite, which created data holes in the computer model. Earlier attempts at printing a 3D replica fell apart.
Eventually, the scientists solved the problem by building several small models of the meteorite, which allowed them to visualize the missing data points. Next, they used software—normally used to create navigation terrain maps for rovers—to generate depth meshes of the meteorite's surface from six positions, which were then combined into a 3D digital model.
Since Block Island was too large to print all at once, the scientists printed out 11 different segments and assembled them together. Total time to print the parts: 305 hours and 36 minutes. NASA says the project opens the door to other detailed models of objects and terrain on Mars, or elsewhere in the solar system.