When NASA's Mars 2020 mission sets down on the Red Planet in three years, it will have a record number of cameras aboard. The unmanned, nuclear-powered rover will carry 23 cameras that will have higher resolution more 3D capability, and larger bandwidth than any previous Mars explorer – including one camera inside the rover's laboratory to monitor sample collection and storage.
It wasn't that long ago that lunar and planetary landers were lucky if they had a camera, much less a number of them. And even if they did, in the days before computer enhancement and remastering the results were often blurry and distorted. But as camera technology has evolved and capabilities improved, the number of cameras that can be carried has increased as their size and cost has decreased.
The first functional Mars lander was the Soviet Mars 3, which landed on the planet in 1971 and was equipped with two very basic video cameras that sent back a partial image before the spacecraft failed after a mere 20 seconds of activity and less than two minutes after landing.
The 1976 Viking 1 and 2 NASA landers used a pair of more sophisticated semi-mechanical scanning cameras that allowed them to take not only conventional, but stereoscopic images, though at a very slow rate of transmission. By the time 1997's NASA Mars Pathfinder mission set down, it had five cameras – two on the lander mast and three on the Sojourner mini rover. Meanwhile, the Spirit and Opportunity rovers that reached Mars in 2004 had 10 cameras each and the Curiosity rover of 2012 had 17 cameras.
But Mars 2020 won't just have more cameras, it will have cameras that are much more sophisticated than anything ever flown on a Mars mission before. For example, Curiosity carries a suite of engineering cameras called Navcams and Hazcams that are used for navigation and avoiding hazards, respectively. These are in black and white and only have a resolution of one megapixel.
The ones on Mars 2020 will be in full color with a resolution of 20 megapixels and will have wider field-of-view lenses. This means they can view an entire scene in a single image instead of panning and stitching smaller ones together, which takes time and can produce motion blur.
Another improvement is the Mastcam-Z (3-D-printed model pictured above), which replaces Curiosity's Mastcam. The Mastcam-Z now has a 3:1 zoom lens and is stereoscopic, so it can take more 3D images than its predecessors. According to NASA, this will allow Mars 2020 to provide 3D "field notes" to contextualize samples and better identify interesting geological features.
Then there's the SuperCam Remote Micro-Imager (RMI), which is the highest-resolution remote imager sent to Mars and now has color; the CacheCam for monitoring rock samples inside the rover; six entry, descent, and landing cameras to record the touchdown of the rover as well as the first opening of a parachute ever seen on another planet; the Lander Vision System Camera that uses computer vision and a new technology called terrain relative navigation to guide the landing; and the SkyCam for studying clouds and the atmosphere.
NASA stresses is that the camera upgrades are made possible by more than improvements in camera technology. The ability to use such sophisticated imagers is also dependent on the new high-speed communication relays that the space agency has been developing. Along with data compression inside the rovers and landers, NASA is now using the Mars Odyssey orbiter as well as the Mars Reconnaissance Orbiter, MAVEN, and the European Space Agency's Trace Gas Orbiter as relays to send large amounts of imaging data more quickly and has already enjoyed promising results from experimental transmissions through NASA's Mars Odyssey orbiter.
"We were expecting to do that mission on just tens of megabits each Mars day, or sol," says Jim Bell of Arizona State University, Tempe, principal investigator for 2020's Mastcam-Z. "When we got that first Odyssey overflight, and we had about 100 megabits per sol, we realized it was a whole new ballgame."
The Mars 2020 Rover and all its cameras are set to launch in July or August 2020, and reach the Red Planet in February 2021.