Phoenix may change the way we think about origins of life
by Marjorie Howard

Visitors to Samuel Kounaves' office are treated to an array of photographs on the wall near his desk: pictures of scientific equipment, of spacecraft, of planets hovering in space. One photograph looks like a scene in Arizona, perhaps. It's not especially inviting but not particularly alien, either. There are boulders strewn around what looks like a light brown desert, a place that looks dry but intriguing. The picture was taken on Mars, a place that has been a part of Kounaves' research since 1996.

An artist's illustration of what the robotic lander Phoenix will look like on Mars when it lands on the planet in 2008.

Kounaves, associate professor of chemistry, is a co-investigator on the $325 million Phoenix Mission, a team of scientists from 17 institutions whose proposal was selected by NASA in August to carry out a mission on Mars in 2007. Phoenix is a robotic lander containing instruments that have three key goals: By landing at high northern latitudes on Mars, it will study an area where a current mission, the Odyssey Orbiter, has determined there is ice near the surface; it will study the history of the water in all its phases with chemical, geological and meteorological measurements; and it will search for habitable zones by assessing liquid water and any organic or biologically interesting material.

"Phoenix has the potential to change the way we think about the origin of life," said Kounaves.

Kounaves had worked on the Mars Surveyor Program, which was scheduled to land on Mars in 2001. That program was cancelled when the Mars Polar Lander was lost while entering the Martian atmosphere near the planet's South Pole in December 1999. NASA later established a competition for a new program, inviting scientists to submit research proposals. Usually, said Kounaves, NASA has its own goals, but this time, the agency asked researchers to come up with a scientific mission of their own. Phoenix was chosen after a nearly two-year competition, beating out 30 other proposals.

Allure of the Red Planet
Of all the planets, Mars has perhaps inspired the most science fiction and the most speculation about life in the form of some sort of alien creature. Around the time Kounaves and his colleagues learned they had received the go-ahead for Phoenix, scientists were alerting the public to the fact that Mars would be at its closest to the Earth in 60,000 years in late August. Kounaves was invited to speak about Mars at the Harvard Smithsonian Center for Astrophysics during that week. There wasn't enough room in the auditorium for the crowd that filled the building, so he ended up giving two talks that night.

What interests people most about Mars, said Kounaves, is the question about whether any kind of microbial life evolved there and if so, what happened to it. While most people, he said, think of Mars as a dusty, dead desert, "it is actually dynamic, with tornados, sand dunes, clouds, frozen water and a climate of its own. Most exciting is that it may have once had oceans covering much of its northern surface."

Phoenix will have two main analytical instruments. TEGA-MS, the thermal evolved gas analyzer-mass spectrometer, will heat soil samples and look for organic material and water content. MECA, the microscopy, electrochemistry and conductivity analyzer, will analyze the soil with an array of sensors and provide information about the soil's chemical composition and what minerals are present that may have formed during a wetter, warmer past climate, and thus whether it has the ability to support life.

A robotic arm on Phoenix will dig up soil samples down to one meter in depth and deliver them for analysis to TEGA and MECA.

Phoenix will also take panoramic photographs as well as pictures from cameras attached to the robotic arm, giving scientists their first-ever views of the subsurface of Mars.

Life's possibilities
Kounaves said it is "surprising" how much ice has been discovered on Mars. "We have found permafrost, just like areas in Canada and the polar regions on Earth," he said. "On Earth, scientists have been able to find microbes in Antarctica and miles underground where it was thought impossible for any life to exist. If life on Earth can exist in such severe places, perhaps it can exist on Mars."

Kounaves had nothing but praise for the way the Phoenix Mission has been organized. "Most of our proposal preparation work was done by e-mail," he said of the intense competition. "We couldn't have done this without the Internet. We had conference calls with everyone looking at the same information on their computer screens. The teamwork and strategy are amazing. I have never worked with such a large and diverse group of scientists: There are chemists, geologists, physicists, biologists and engineers."

This view of Mars, obtained from the Hubble Space Telescope, shows the Martian North Pole at the top (near the center of the bright polar cap). This image was taken on the last day of Martian spring in the northern hemisphere, and clearly shows familiar bright and dark markings known to astronomers for more than a century.

Once Phoenix lands, it will provide several years of data to analyze, which will mean even more funding. Some of the money supports both undergraduate and graduate students who have been working on the project with Kounaves.

Kounaves was originally invited to participate in MECA because of the research and development he had done on electrochemical sensors funded by the U.S. Environmental Protection Agency to assess contaminated Superfund sites. The EPA needed rugged sensors for harsh environments that had to be small enough to go into wells to measure heavy metal contaminants in water or sediments. The same kind of sensors will be used on Mars.

For many years, Kounaves said, he has wanted to address some of the basic scientific questions dealing with understanding the potential for origins of life on other planets. "Our research is focused on unraveling fundamental questions in planetary science using the techniques of modern analytical chemistry and electrochemically based sensors," he said. In the future, Kounaves said he is also interested in applying the same techniques to investigate the sub-glacial oceans on Jupiter's moon, Europa.