This artist's concept features NASA's Mars Science Laboratory Curiosity rover, a mobile robot designed to Mars' past or present ability to sustain microbial life. Photo by NASA/JPL-Caltech.
NASA scientists call it the seven minutes of terror: the amount of time it will take the Curiosity rover to plunge through the Mars atmosphere and deploy a massive parachute and sophisticated landing system called a sky crane and then -- hopefully -- touch down safely on the surface of the Red Planet.
Then for 14 minutes, scientists will wait as the radio signal travels the 150 million miles from Mars to Earth. NASA created this video on the suspense of those seven minutes.
Sticking that landing will make the one-ton, Mini Cooper-sized rover the seventh craft to land on Mars. This graphic from NASA's Goddard Spaceflight Center shows the landing sites of the six that are already there -- Viking 1, Viking 2, Pathfinder, Spirit, Opportunity and Phoenix -- plus the target location where they're hoping Curiosity will touch down.
Curiosity is expected to complete its nine-month, 354-million-mile journey to Mars on August 6. NASA's 11-year-old Mars Odyssey spacecraft, which is orbiting Mars, has been repositioned to track and provide confirmation of the robot's landing.
If all goes as planned, it will land about 4.5 miles south of the planet's equator on the ancient Gale Crater, which Richard Cook, deputy project manager of the Mars Science Laboratory mission called "the Grand Canyon of Mars" in an interview last year.
But it's like an inverse Grand Canyon, said astrogeologist James Rice, who was involved in selection of the landing site. The Gale Crater, he said is 96 miles in diameter and includes a mountain of layered rock that rises three miles high and includes clay and sulfate minerals, a possible indicator of water.
The rover's main mission is to search for signs that the planet was once suitable for life, life's chemical building blocks. That could mean organic material, methane, carbon-rich soil, anything that indicates the planet once hosted water.
To have life, Rice said, you need liquid water, an energy source -- which could be sun or volcanic energy -- and organic materials.
"You have to have all three -- they're the common denominators for life," he said. "But if you have all three, it doesn't guarantee you have life."
Curiosity is hauling a sophisticated set of instruments to Mars to sleuth for those signs, such as an arm equipped with a rotary percussive drill to take samples. Cook explains how that will work here in his interview with Hari Sreenevasan from the mission's launch last November.
"We're actually going to drill into the rocks on Mars and take that powder that comes out of those rocks and feed it into the instrument," he said.
The drill tools on its arm will deliver the samples to a laboratory inside the rover. There it will heat, study and X-ray the samples to understand their chemistry.
"We know there was water on Mars, we know heat sources were there - in the past Mars had volcanic activity," Rice said. "The one we don't know is whether organics were there. This will check that box."
