The Camera Behind the New Pluto Photos - How to build a camera that travels billions of miles from Earth
“We were cruising for nine and a half years,” Hardaway told me. “So our system would have to handle the space environment, specifically radiation and thermal fluctuation, for nine and a half years.”
“Going out that far, there are some fluctuations,” Hardaway says. “It can get quite cold, and materials will shrink as they get colder. But different materials shrink at different rates.” The answer, then, was to build almost the entire camera out of just one type of material. “We actually built the mirrors and the chassis out of aluminum so that as they shrink, they would shrink together, to maintain the same focal length. We could do a reasonable test on Earth and still expect the same quality image,” she says.
Even the camera’s mirrors were made out of aluminum. (To turn dull aluminum into mirrors, Ball sharpened it with diamonds.) The lens was one of the few pieces of the camera that could be safely made out of glass.
Full article: http://www.theatlantic.com/technology/archive/2015/07/the-camera-behind-the-new-horizons-pluto-photos-ralph/398549/