THE WASHINGTON POST – Images of Mars from the past decade have shown amazing craters, dust storms and colourful mineral deposits. The photos come from the most powerful camera ever sent to a planet. It’s called High Resolution Imaging Science Experiment, or HiRISE, and it’s helping scientists understand the planet where NASA has sent rovers and where it may send humans.
Launched in 2005, the camera was designed to take detailed photos while orbiting the Red Planet. HiRISE has transmitted nearly 69,000 images since 2006 and is still sending pictures. The images are colour-enhanced to allow scientists to see important details their eyes could not ordinarily detect.
HiRISE photos helped NASA evaluate potential landing sites for the Perseverance rover to explore. Scientists selected Jezero Crater, a dried lake where they hope to find signs of ancient life on Mars.
The cost to build and launch Perseverance was about USD2.4 billion, so NASA wanted to make sure it landed safely. NASA turned to HiRISE and studied 81 images of Jezero Crater to determine a safe landing target within the crater.
“We’re looking for a nice level area we can drive out of with no troubles,” said Rich Zurek, project scientist for the Mars Reconnaissance Orbiter. “We want to avoid hard things that are big, like rocks, and we want to avoid soft things like sand, that don’t provide good traction.”
After Perseverance landed February 18, HiRISE continued to play a key role in the mission.
“You can see the rover tracks with the HiRISE camera,” Zurek said. “You can see where it’s going and where it’s been.”
When you’re operating a robotic rover from about 140 million miles away, the ability to see its path is invaluable.
HiRISE images have also given scientists a new understanding of what many people thought was a “dead planet.”
“The largest breakthrough in Mars science that we’ve learned from HiRISE images is that there are active geological processes at work today,” said Candice Hansen, HiRISE deputy principal investigator. “Prior to HiRISE, the conventional wisdom was that all the ‘action’ on Mars happened billions of years ago.”
The camera takes many images of the same place at different times, which allows researchers to detect changes on the surface.
“We’ve seen avalanches off the northern polar cap,” Hansen said. “We’ve seen dunes migrate.”
Scientists have even calculated how fast Mars’s dunes travel – up to three feet in a Martian year (687 Earth days) – by examining HiRISE photos taken at different time intervals.
Using HiRISE images, researchers are studying many of Mars’s changing features, such as canyons, ice and craters.
For example, one photo of an impact crater with steep slopes contained clues that led scientists to believe water may be seeping down its slopes.
The sharp rim indicated it’s a fresh, young crater. (Impact craters form when a meteoroid, asteroid or comet collides with a planet or moon.)
So what’s next for HiRISE?
“We’ve only covered less than four per cent of Mars surface at the HiRISE resolution,” said Zurek.
If all goes well, this powerful camera will continue to operate and answer questions about the Red Planet for years to come, Zureck said. “We hope it will go for another decade.”
– The HiRISE camera is orbiting Mars between 125 and 250 miles from its surface.
– HiRISE is riding on a spacecraft called the Mars Reconnaissance Orbiter, or MRO.
– It takes HiRISE images 15 minutes to travel roughly 140 million miles back to Earth.
– To see more fascinating HiRISE images, check out the catalogue at uahirise.org/catalog.