The true color, high-definition cameras
What fun is trundling around another planet with cutting-edge rovers if they can’t grab lovely images of it? To that end, Curiosity wields a variety of cameras, including two capable of capturing images at 1600 x 1200 pixels as well as high-definition video at 720p and up to 10 frames per second — specs unprecedented for a rover mission.
“You can think about the Curiosity’s camera system in two ways,” says Vasavada. “In one sense, they’re all a generation or two behind what’s available at Best Buy, because of how we go about qualifying equipment to work in space, but on the other hand, from the Mars perspective, they’re the best cameras we’ve ever flown.”
(PHOTOS: Roving the Red Planet)
Take color, for instance, which all prior Mars cameras have lacked, instead snapping unflattering grayscale pictures and requiring RGB filters to build up a color image — a process that requires three times as many images.
“Now we employ what are called Bayer filters, which are exactly what’s now on all consumer cameras,” says Vasavada, referring to the micro-RGB filters located on a camera’s detection technology itself. “Every time you take a picture, you’re taking a color picture inherently.”
But where the original proposal for Curiosity’s camera system was very ambitious, one of the coolest-sounding features didn’t make the final cut.
“We were originally looking at 15-to-1 optical zoom cameras, both a left and right stereo pair,” says Vasavada, referring to the camera system that at one point had filmmaker James Cameron’s attention. Unfortunately it was a little too ambitious. For instance, Vasavada says the system would have had to fit inside something as small as a lipstick tube.
“About halfway through, we decided to cut our losses and keep all the other capabilities,” says Vasavada. “And we did something interesting, which is that we decided not to have matched left and right cameras.”
NASA loves its panoramic shots, like the latest head-turner recently assembled from a whopping 817 images snapped by the Opportunity rover. Zoom capability would have allowed NASA to zoom out and snap just four or five pictures to assemble a panorama, or, alternately, zoom in to take a high-res panorama of something like a rock in the distance.
“We decided, when we got rid of the zoom capability, to leave just one of the cameras as a kind of telephoto lens, and the other cameras as a medium angle lens. So we have one camera that takes about a three times higher resolution image than the other camera, and they’re both capable of color and high-definition resolution.”
The radio communications system
Curiosity has two ways to talk to us on Earth: a high-gain X-band receiver (Vasavada says it resembles a giant lollipop) that can chat direct with Earth with distance-related delay times of just under 14 minutes, and a UHF radio that can talk to the spacecraft currently orbiting Mars, operating as relay stations.
“Both have their advantages and disadvantages,” says Vasavada. “The upside of talking direct is that you don’t have to rely on an Orbiter, which since it’s orbiting the planet, isn’t available at all times. The downside is that you have to aim it at Earth, so you have to first find the sun in the sky and reorient the Rover. But once you get that going, the direct antenna is the one we’ll use to upload a day’s worth of commands.”
Vasavada says there’s even a third way to talk to Curiosity in a pinch: a low-gain antenna that doesn’t have to be aimed, allowing the rover to simply signal that it’s there or receive rudimentary commands like “reboot.”
CheMin and SAM
“The primary way we look at ancient rocks on Mars to determine if they represent a habitable environment is to acquire samples of the rock with this big power drill that’s on the end of Curiosity’s robotic arm,” says Vasavada. “So we actually jackhammer into rocks, acquire the powder we’ve created and then deliver that powder to two core instruments that we call our laboratory instruments.”
One of those instruments is dubbed CheMin (for “Chemistry and Mineralogy”) and the other is called SAM (for “Sample Analysis at Mars”). Vasavada says these comprise Curiosity’s “core” laboratory capabilities.
CheMin uses technology called X-ray diffraction to shine an x-ray beam through the powdered rock and create diffraction patterns (“Basically like rainbows,” says Vasavada) allowing scientists to discern the rock’s mineral composition, which in turn helps build a much more thorough picture of the environment.
“This is the gold standard technique that’s used on Earth to identify minerals in any sample, and we’re bringing it to Mars for the first time,” says Vasavada.
And then there’s SAM, which includes both a mass spectrometer and a gas chromatograph, giving it CSI-like capabilities, according to Vasavada. Vasavada says SAM is “the biggest, most complex instrument Curiosity carries,” adding, “You could say it’s the one the entire rover was built around.”
When you deposit samples for analysis in SAM, for instance, the mass spectrometer can determine, element by element, what the chemistry of the sample is, while the gas chromatograph is used to separate different chemical compounds from each other and detect organic compounds that contain carbon.
“Organic compounds are where things get really interesting if we find them on Mars, because they could be used as building blocks of life,” says Vasaveda. “Or, and I don’t know if we’ll be able to tell this for sure, they could even be the remnants of life.”