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Published: 2014-06-25 10:13:00
Updated: 2014-06-25 10:14:21
Posted June 25, 2014
By Tony Rice
Raleigh, N.C. — Exactly one Martian year ago (687 Earth days), I was standing behind the podium in the North Carolina Museum of Natural Sciences theater shortly after 1 a.m. watching the Mars Curiosity rover land.
In front of a standing-room only crowd, I had the task of “talking down” the rover, attempting to describe steps as they happened during entry, descent and landing. The evening began with talks from my fellow NASA Solar System Ambassadors on propulsion systems that got us to Mars, instruments aboard the rover and what geology might reveal about Mars history. Similar events were held at NASA centers around the country. even in New York City's Times Square.
Since landing, Curiosity has traveled 7.95 km (4.94 miles) and gained 48.14 meters (157.94 feet) in elevation over 200 drives. Within weeks of touchdown, the primary mission, a search for signs of conditions necessary to support microbial life, was achieved.
Curiosity landed on an ancient riverbed containing key ingredients for life, including sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon. The pH of clay minerals in the rock even suggests that ankle deep fresh water once flowed there.
“If this water was around and you had been on the planet, you would have been able to drink it,” according to Curiosity chief scientist John Grotzinger.
Perhaps the biggest accomplishment was successfully landing the 1-ton robotic geologist/chemist/meteorologist and doing it all on autopilot.
At the time of landing, nearly 14 minutes were required for signals to travel the 154 million miles from Mars to Earth, twice the time it took to get from the top of the atmosphere to the planet's surface. Any problems had to be handled by the rover’s programming.
Each stage of the landing was tested thoroughly, often in full scale on Earth. However, end-to-end testing is only possible in computer simulations until we figure out a way to simulate Mars gravity here on Earth.
Crowds that gathered to watch the landing sat on the edge of their seats waiting word from mission control. It was Jody Davis, a flight engineer from Langley Research Center (LRC) in nearby Hampton, Va., who shared those first words: “tango delta nominal,” using the phonetic alphabet to indicate the first signs of touchdown.
Other than a few gasps, you could hear a pin drop in the auditorium. Eight long seconds later came “RIMU Stable” from David Way another LRC based engineer. The Rover Inertial Measurement Unit indicated the spacecraft was resting its wheels, another very good sign.
The indication the team was waiting for came from communications engineer Brian Schratz: “UHF strong” an indication that the rover was communicating well with Earth and had successfully detached from the sky-crane. Jody and several other LRC EDL engineers visited the museum for Astronomy Days several months later.
EDL Lead Allen Chen barely got out "touchdown confirmed, we’re safe on Mars" before cheers erupted at mission control and in Raleigh. Within minutes. it got even better as we were treated to the first images from Gale crater with the 5.5 km (18,000 ft) tall Mount Sharp in the background. After the adrenaline had worn off, the bleary-eyed crowd headed home with the knowledge they had a "I was there when" story.
After a (Martian) year exploring the crater floor dating back to about the time when oceans formed on Earth, the rover will spend the remainder of the mission scaling Mount Sharp.
The layered mountain offers a time machine of sorts with increasingly more recent geologic formations to study. Researchers are eager to use what is learned to answer the big question facing Mars: what changed it from the once warm, ocean covered planet to the cold, dry planet it is today.
Tony Rice is a volunteer in the NASA/JPL Solar System Ambassador program and software engineer at Cisco Systems. You can follow him on twitter @rtphokie.