By Mary O’KEEFE

After three years of traveling over the Martian surface the robot Opportunity has arrived at Endeavour crater to begin studying rocks that have never been seen before.

Opportunity and its twin rover Spirit were launched in the summer of 2003 and completed their 90-day prime mission in April 2004. However the “little rovers that could” continued to explore the Martian surface well beyond their prime mission was over. Recently Spirit exploration ended after it got stuck in the Martian sandy surface, but Opportunity continued to roll.

After exploring and climbing out of Victoria crater, Opportunity traveled about 13 miles to what scientists have named Spirit Point on the rim of Endeavor crater. The location is of interest to scientists because of the older rock and terrain. Deciding on a location to study is a joint effort between data gathered in the past and satellites that orbit the planet. Mars Reconnaissance Orbiter had detected clay minerals in the crater that may have formed in an early warmer and wetter period.

As Opportunity continues its exploration, the new rover Mars Science Laboratory (MSL), or Curiosity, is preparing for its launch.

After five years of brainstorming, debates and friendly discussions a landing site has been chosen for Curiosity.

“We had five workshops, starting about five years ago,” said Ashwin Vasavada, deputy project scientist for Curiosity at the Jet Propulsion Laboratory.

There was an open invitation to all scientists who work on Mars projects or Earth models of the Martian surface to participate in choosing the location.

“It is kind of a long process [but] NASA wants to involve the entire community of scientists,” Vasavada said.

About 125 people attended the meetings that began with an open discussion when any scientist could propose a site based on their research. Those initial suggestions were narrowed down to about 60 sites, then those were trimmed to 30 sites, then to 10, Vasavada said.

In 2008 it was down to four site candidates.

“We have been studying [those four] since then,” he said.

The scientists used models, past research data and images from Mars Reconnaissance Orbiter to find the local that would best tell the history of Mars, and keep within the goal of all Mars missions – to “follow the water.”

Water equals life, so the search for water may answer the millennium old question of whether there is, or was, life on Mars.

“The [Gale crater] site offers a visually dramatic landscape and also great potential for significant science findings,” stated Jim Green in a prepared release. Green is the director for the Planetary Science Division at NASA headquarters in Washington.

“Gale gives us attractive possibilities for finding organics, but that is still a long shot,” stated Michael Meyer, lead scientist for NASA’s Mars Exploration Program at agency headquarters. “What adds to Gale’s appeal is that, organics or not, the site holds a diversity of features and layers for investigating changing environmental conditions, some of which could inform a broader understanding of habitability on ancient Mars.”

Vasavada said the crater has layer after layer of sediment. Curiosity can examine those layers much like paleontologists study the layers of sediment on Earth to help develop a timeline of Earth’s history.

The two rovers, Spirit and Opportunity, that preceded Curiosity were smaller than a small golf cart. Curiosity is twice as long and more than five times as heavy, about the size of a Volkswagen. It will have more ability to study the surface of Mars as well with its 10 science instruments including two for ingesting and analyzing samples of powdered rock that the rover’s robotic arm collects.

As with every mission to Mars there are high hopes tempered with scientific reality. It is a foregone conclusion however that once Curiosity lands it will discover new information about the planet. Vasavada has seen several landings on Mars and is anxious to begin the mission and to receive the first data from Curiosity.

“To see it with our own eyes, that there [was once] a water canyon. We really have a chance to find it on this mission,” he said.

Curiosity is targeted to launch from Cape Canaveral Air Force Station in Florida between Nov. 15 and Dec. 18. It will arrive on Mars in August 2012. NASA’s JPL manages the mission.

  Mary Okeefe