For decades after its discovery in 1930, Pluto looked like nothing more than a gray smudge in the abyss of space. We knew it was there—even knew its size and gravity—but, without better images, we could not answer seemingly basic questions about it. Was it pocked by craters? What was its atmosphere like?
Our understanding of the orb has slowly improved (with the Hubble Space Telescope’s help), but this week it takes a cosmic step forward. On Tuesday morning, NASA’s New Horizons probe zipped by Pluto and its dwarf moon, Charon. After a nine-year journey from Earth, New Horizons took hundreds of images in mere hours on Tuesday—images that will fill textbooks and museum exhibits for decades, as well as help scientists figure out how our solar system came to support life.
There are three cameras aboard New Horizons.
I talked to Lisa Hardaway, an engineer at Ball Aerospace in Colorado who led technical development of the one called “Ralph.” Ralph captures visible and some infrared light. When you see Pluto looking tan- and sepia-toned in the new, high-resolution photos, you’re looking at data captured by Ralph.
Since it captures visible light, Ralph is in many ways comparable to the camera found in a phone or fancy DSLR. In conventional camera terms, it’s a 75mm lens at f/8.7. But it was far harder to built than a normal camera. Hardaway says that the team was working under a number of big constraints.