Drawing: Mars rover mission
Corby Waste  /  NASA
Clues that part of Mars may have been soaked with water have opened discussion on the best way to further explore the Red Planet.
By Senior Space Writer
updated 3/5/2004 2:46:26 PM ET 2004-03-05T19:46:26

The early eye-opening results from NASA’s Opportunity Mars rover mission are helping shape the scope, direction, and timing of future robotic missions to the red planet -- and how soon humans will be Mars bound.

The tell-tale clues that Meridiani Planum was water soaked at one time have opened the floodgates of discussion in how best to study Mars in ever-greater detail, as well as sharpen our search for past and even present life.

Already on the books is a potent flotilla of NASA Mars craft, such as the Mars Reconnaissance Orbiter for 2005, the Phoenix Mars lander in 2007, and a Mars Science Laboratory rover for 2009.

But thanks to glimpses provided courtesy of both Spirit and Opportunity, Mars never looked better.

Rewrite the text books
The revelations relayed back to Earth by Opportunity have spotlighted future Mars exploration needs for the next decade, said Ed Weiler, NASA head of the Office of Space Science.

"It’s clear we’re going to have to do a sample mission," Weiler said during Tuesday’s Mars press briefing at NASA Headquarters in Washington, D.C. Money needs to be also spent on miniaturizing equipment for transport to Mars. Another priority is to land instruments that pave the way for eventual human landings on the red planet, he said.

Gauging the toxicity of martian soil has to be done, Weiler said. Also, how best to use the minerals on Mars for conversion to oxygen, or to power rockets is high on his action item list.

Some future work on Mars may be totally science oriented, Weiler said, some may be totally human preparation oriented. "I have a feeling that all of the missions are going to be a mix of those two things," he said.

Predicting right now what those missions might look like -- other than a sample return next decade -- is dangerous, Weiler said.

"Mars doesn’t tend to read our textbooks. It tends to write them for us. And rewrite them every time we send a mission," Weiler concluded.

Complicated planet
Bits of Mars back in the lab are needed, not only to unravel in a lot more detail what the planet’s geological history has been, but also to address the questions about life.

That’s the view of Bruce Jakosky, professor of geological sciences and Director of the Center for Astrobiology at the University of Colorado, Boulder. "I think that answering the question about life [on Mars] is going to take a sample return," he said.

Slideshow: Week 9 Mars is a complicated planet, Jakosky said. "I think what we’re seeing is that things are not globally uniform. There are environments where liquid water does quite well…and probably places where there hasn’t been any. And we now know that in at least one place it’s a great environment for life at some time in the past," he said.

Jakosky said that NASA is also evaluating the role of a possible Astrobiology Field Laboratory. That rover would haul science gear tuned specifically to peruse Mars for traces of life.

"Every time we have sent a new spacecraft to Mars, we might have as well sent it to another planet…because we see it’s very different from what we’ve expected. We are not just learning about the same processes in more detail. Each time we send a new spacecraft, a new instrument, or visit a new site, we learn about an entirely unexpected suite or processes," Jakosky told SPACE.com.

Major shot in the arm
The upshot from Opportunity’s survey work has rocketed throughout the science community.

The output from Opportunity is enthralling, said David Grinspoon, Principal Scientist in the Southwest Research Institute’s Department of Space Studies, Boulder, Colorado. "Through exploration, we can learn something definite about whether we have living company in the universe beyond Earth. Well, the universe has just dropped us a big hint."

Grinspoon recently authored the book: Lonely Planets: The Natural Philosophy of Alien Life (HarperCollins, November 2003).

"This discovery proves that Mars is indeed an important place for astrobiology exploration – a place that should have had life in the past, given our current understanding of life and evolution, a place where we can and should look for fossils of bygone creatures," Grinspoon said.

Thanks to the Mars rover, confirmation has overtaken growing suspicion, Grinspoon said. There are places on Mars which were at one point habitable according to certain untested but widely assumed criteria for what a planet needs to support life, he said.

"We now know that we can go and test our current ideas about life by looking for fossils in these places on Mars, Grinspoon explained.

Among other things, Grinspoon added, the rover’s findings will be a major shot in the arm for desires and plans for a future mission that returns martian samples to Earth. "With the right Mars rocks in terrestrial laboratories we will be able to more definitively test the idea that life once graced our red planetary neighbor," he said.

First encounter
Mars history is locked away in the rocks at the Opportunity site, said Jim Rice, a team member of the Mars Exploration Rover Project from Arizona State University in Tempe.

"This is an amazing story. You have Meridiani Planum sitting there looking very unassuming and frankly sort of boring compared to the vast awe inspiring canyon complexes of Valles Marineris and the gargantuan Tharsis volcanoes," Rice told SPACE.com .

Meridiani Planum is a vast, relatively flat and smooth featureless plains region, Rice noted. "Yet it is this very site that will go down in the history books as the first encounter we’ve had with the past presence of liquid water on another world other than our own home."

Slideshow: Mars halftime show The story of Spirit and Opportunity is far from over, Rice predicted. "That proverbial fat lady hasn't even thought so much about humming yet…her singing is a long, long way off."

Rice likened the Mars rover science team as the 21st century equivalent to Lewis and Clark's Corps of Discovery that were exploring and discovering a new land 200 years ago.

The future of Mars exploration by both robots and humans is today arguably the best it has ever been, Rice said. "Opportunity’s findings -- combined with the President's new space exploration initiative -- make it a great time to be a Mars scientist," Rice stated.

While the rover missions at Gusev Crater and Meridiani Planum continue to be on a roll, several technical points have already come to the forefront.

The importance of mobility on Mars has proven critical, said Benton Clark, Chief Scientist of Space Exploration Systems at Lockheed Martin Space Systems in Denver, Colorado. As a Mars rover team scientist, he said that Opportunity’s ability to use its Rock Abrasion Tool in two outcrop spots just 17 inches (44 centimeters) apart made a big difference in science results.

"The mobility has proven itself. A lander wouldn’t have worked," Clark said. "You had to drive to them."

Clark said that the environmental conditions found by Opportunity are not incompatible with some bacteria we know about here on Earth. The robot, however, is not outfitted with the right science gear to measure organic materials, he said.

The Phoenix Mars lander in 2007 is equipped to dig down in the martian topside and probe for ice. "It will be very important to get down and see if ice is really there. Finding organic compounds in that ice would be another huge smoking gun for life," Clark said. The follow-on Mars Science Laboratory in 2009 could carry sophisticated drilling gear to help understand what lies beneath the martian landscape, he said.

Clark said the Opportunity landing site at Meridiani Planum is a great place for building up a human outpost.

New generation of instruments
The Opportunity findings show that the strategy of "follow the water" was the right direction to pursue, said Geoff Briggs, Scientific Director of the Center for Mars Exploration at the NASA Ames Research Center at Moffett Field, California.

Briggs said that the forthcoming Mars Science Laboratory mission will carry a new generation of instruments to help decipher "in the field" the history of the red planet.

The prospect of a returning to Earth soil and rock specimens from Mars next decade, while sure to be scientifically rewarding, would also flex the technology muscle to eventually send humans there, Briggs said.

Over the years, Briggs said, robotically returning samples from Mars has been inhibited by two things: high cost and high risk.

The NASA initiative that calls for humans to Mars in the foreseeable future, Briggs said, should give more programmatic support and the funds to make a robotic return sample effort happen before astronaut explorers set foot on the planet.

Briggs said that, ever since the Viking landers of the mid-1970s, robotic missions to Mars show the orders of magnitude difference between humans and automatons - in terms of speed and job performance.

"I've always been an advocate of sending human explorers to Mars because the science is very challenging and humans will do so much more in a fraction of the time," Briggs stated.

Nail in the coffin
Not to take anything away from the robots, Spirit and Opportunity also show their limitations when put up against flesh-and-bone investigators.

"I’ve maintained for some time now that Gusev was going to be a difficult story to untangle…and I think that was a correct prediction," said Ronald Greeley, planetary geologist from Arizona State University and a Mars Exploration Rover scientist.

The Athena science package carried on both Spirit and Opportunity is well-suited to investigate Mars, Greeley said. "You have to take all the pieces and put them together. No one of them is likely to be the nail in the coffin," he told SPACE.com .

Greeley underscored the fact that the robots are doing an impressive job at Gusev Crater and Meridiani Planum. However, the robots also point out just how invaluable humans are in conducting on-the-spot science.

Slow-going science
One early message from Mars, Greeley said, is the slow-going nature of Spirit and Opportunity machinery. Even the easiest of tasks performed by a human, when attempted by the robots, turns into a painful process, he observed.

"The frustration does enter when you want to go from here to over there and do something. The rovers have got to go through an awful lot of machinations just to do the simplest of things," Greeley said.

Compared to robots taking a day or two on Mars to perform duties, human explorers could quicken the pace of work."

The eye-brain is a marvelous combination of things that machines can’t begin to touch. The things Opportunity is doing at the outcrop, humans could do pretty quickly," Greeley said.

As example, a human standing where Opportunity is now exploring would not be fooled when eyeing the outcrop of rocks. For the robot, the viewing geometry and illumination it surveys are fixed, Greeley said. A flesh-and-bone geologist could instantly move about to rapidly consider whether or not a scientific interpretation was or wasn’t correct.

"With the rover, you’ve got a fixed perspective. You don’t have the luxury of doing a lot of finagling," Greeley added.

Mars underground
Similar in view is Penny Boston, Research Associate Professor of Cave and Karst Science at New Mexico Tech’s Department of Earth and Environmental Science in Socorro, New Mexico.

"Let any of us go up there with a geology hammer and a good microscope. We’d already have a lot of answers. But keeping us alive, that is really the sticky point," Boston said.

Boston said that the rover work on Mars has been impressive. But it’s clearly not the last word on the problems of underground Mars – where ground water and brines still could exist, along with martian biology that might be alive and well today.

"I’m excited about the surface water…but it’s pretty premature to draw any serious biology conclusions," Boston said.

Opportunity’s water find is vindicating, Boston said, and blows open the whole issue of looking for sedimentary rocks.

"There’s clearly a lot of sedimentary action that has gone on in the past. And where there are sedimentary rocks on Earth there are organisms. They are inextricably bound with that on this planet. It remains to be seen whether they are inextricably bound with the history of water and sedimentary rocks on Mars," she said.

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