For the past decade, the High Resolution Imaging Science Experiment — a $40 million camera on board the Mars Reconnaissance Orbiter — has been taking photographs of Mars and its rocky, ever-changing surface.
The spacecraft orbits about 200 miles above the massive planet, but it is powerful enough to zero in on objects as small as three feet across — about the size of your desk at work.
Since it began orbiting the Red Planet in 2006, the HiRISE camera has captured about 50,000 images, thousands of which were commissioned by curious members of the public.
Ingrid Daubar, a research scientist at the Jet Propulsion lab in Pasadena, Calif., told The Washington Post that HiRISE is the largest camera ever sent to another planet and it's known among experts as “the people's camera.”
“I haven't looked at all of the photos, but I think some of the images are beautiful,” said Daubar, who spent nine years on the HiRISE operations team. “Some members of the public are prolific photographers.”
Members of the public don't actually shoot the images with a joystick, but they do play a significant role in identifying target locations for HiRISE to photograph. After selecting a location using NASA maps online, amateur photographers can request that scientists train the camera on their target of choice, often with a persuasive written explanation.
HiRISE team members review the suggestions before adding approved requests to an extensive planning schedule created several weeks in advance.
Planners consider what can be gleaned scientifically from each potential image and whether the photo request aligns with the spacecraft's timeline, as well as the operational schedule of a series of radio dishes around the world that are in contact with the orbiter when they're facing Mars.
“A lot of coordination goes into a single photograph,” Daubar said. “But in the end you can get an image of your favorite crater. There are also valleys and volcanoes and cool geologic formations that people are drawn to.”
Despite taking tens of thousands of snapshots of the Martian surface, Daubar said, HiRISE has only mapped about two percent of the planet's surface.
“The camera operates in visible wavelengths, the same as human eyes, but with a telescopic lens that produces images at resolutions never before seen in planetary exploration missions. These high-resolution images enable scientists to distinguish 1-meter-size (about 3-foot-size) objects on Mars and to study the morphology (surface structure) in a much more comprehensive manner than ever before.”
So far, Daubar said, the images have yielded valuable insights about the Red Planet's surface, which is much more dynamic than scientists initially thought. The images have revealed never-before-seen gullies, craters and valley networks, as well as seasonal changes among the planet's polar caps, which form “crazy patterns” in the layers of dust and ice.
She goes into more detail about the mapping process and her interest in craters in a recent episode of Spacepod.
Many of those images will be featured in “Mars: The Pristine Beauty of The Red Planet,” a book of curated images being published by the University of Arizona Press this year.
“With tantalizing and artistic glimpses at actively eroding slopes, impact craters, strange polar landscapes, avalanches, and even spectacular descent pictures of probes like the Phoenix Lander and the Mars Science Laboratory, we see what researchers are seeing,” the book's description says.
HiRISE's practical function goes beyond producing artistic imagery and helping scientists map the vast planet. The camera is also searching for locations for NASA's upcoming Mars 2020 mission. So far, the agency says, it has located three areas for “further evaluation.”
Daubar said one of the perks of the images is that they have given scientists a chance to compare particular locations over time, a practice that has led to unexpected discoveries.
“We've actually been able to see current geologic activity going on and we've found that Mars is actually a much more active planet than anyone realized,” she said. “We're seeing new craters and dunes move around and we're actually seeing the craters being formed, as well as avalanches and landslides.”
“It's all happening right before our eyes,” she added.