Sarah Kaplan
Washington - In one photo, the rover's wheels sit atop an expanse of reddish dust pocked with pebbles. In another, there's a cluster of small rocks full of spongelike holes.
That dark feature in the distance - could it be a cliff face? Did these deposits form from a volcanic eruption, or are they sediments left behind by vanished water?
In the 24 hours since NASA's Perseverance rover touched down on Mars on Thursday, scientists and engineers have been ecstatically scouring every image it sends back to Earth. The mission to search for signs of ancient life on the Red Planet has been years in the making. Now, pictures of the rover's perilous descent and perfect landing offer the first clues about the place they've chosen to explore.
Over the coming days and weeks, engineers will begin to deploy the sophisticated cameras and other instruments that can reveal the composition of the rocks and the history of the surrounding landscape. It will take years, if not decades, for scientists to determine whether life ever dwelled here.
For now, they're happy goggling at the pictures.
Scientists were rendered almost speechless by the image taken from the rover's rocket-powered descent stage Thursday, mere seconds before it gently lowered the robot to ground.
In the photo, the rover dangles from four cables, its six wheels poised barely 20 feet above the rocky surface. An electronic umbilical cord spirals up to an unseen spacecraft, while plumes of dust puff upward at the vehicle's approach.
"The clarity, and just - the reality of it," Pauline Hwang, strategic mission manager for the rover's surface operations, said at a news briefing Friday. A veteran of four Mars missions, Hwang has seen her share of landings. But this was the first time a camera had captured some of the "seven minutes of terror" that occur between the second a spacecraft enters Mars' atmosphere and the moment it touches down.
"We just - it was just - it was unbelievable," Hwang said. "All of us just gazed in awe last night."
NASA on Friday also released an image taken by the Mars Reconnaissance Orbiter, a satellite positioned above Perseverance's landing site at Jezero Crater. It shows the faint bright blur of the spacecraft hurtling above the vast desolation of the Red Planet.
Early images taken by the rover's engineering cameras depict the robot positioned on relatively level ground.
"When I look at this image, first of all, I feel a great sense of relief," Aaron Stehura, the entry, descent and landing flight system engineer, said Friday. "I see a landing site that looks relatively safe."
The spot has tremendous scientific significance. The rocks beneath the rover date back more than 3.5 billion years, to the time when Mars had a thicker atmosphere and liquid water on its surface, said deputy project scientist Katie Stack Morgan. Back then, a sprawling river delta spilled into a lake that filled Jezero Crater. If any microorganisms swam in those waters, their fossils might be preserved in the sediments that accumulated in the delta.
When Perseverance's first images came down overnight, "our chats just lit up with the science teams saying, 'Look over here,' " Stack Morgan said Friday. "We're picking out different colours and tones and textures, trying to figure out what these rocks might represent."
And they're already debating what route the rover should take to reach the cliffs of the delta.
"Between us and the delta, we have a lot of interesting science to do," Stack Morgan said.
Landing on Mars is notoriously difficult; about half of all missions to the planet have failed. But Perseverance is the ninth NASA spacecraft to reach the surface of the Red Planet. It is also the second mission to use the ambitious "sky crane" technique.
Perseverance's voyage will be better documented than any other interplanetary mission in NASA history. There are 19 cameras on the rover, plus four more on parts of the spacecraft involved in Thursday's entry, descent and landing. NASA expects to release video of the terrifying landing process in the days ahead.
Microphones affixed to the rover were set to record the spacecraft's arrival at the Red Planet and capture sound throughout its mission. Stehura said Friday it's not yet clear whether the microphones captured audio during the descent.
Perseverance's machinery is in good condition, Hwang reported Friday. Engineers have released the high gain antenna it will use to communicate with Earth. Soon, they'll command the rover to raise its head (called the mast) and start photographing its surroundings with more powerful cameras.
Once the rover has gotten a software update and a clean bill of health, it will drive to a flat spot that can serve as a landing pad for the small, experimental helicopter that hitched a ride on the robot's underbelly. Engineers will spend about 30 days testing out the helicopter, named Ingenuity - the first-ever experiment in controlled, powered flight on another planet.
Then, Perseverance will spend at least the next two years traversing the landscape in search of potential fossil-bearing rocks, which it will collect and store in sterilized tubes. NASA and the European Space Agency are in the early stages of designing follow-up missions to retrieve the sample tubes and return them to Earth, where they can be studied in state-of-the-art laboratories.
