Phoenix Mission to Mars Holds Suspense for ODU's Ash

Robert Ash admits that no one he knows is switching channels from the NBA championships to catch the news and the images coming from the Mars lander Phoenix, which touched down on the Red Planet two weeks ago. But the Old Dominion University aerospace engineer has invested three decades in Mars mission research, and for him just now a robotic arm digging in the dirt 100 million miles away is more exciting than any sporting event could possibly be.

In a word, Ash is interested in water on Mars, how much is there and where. "I'm dying to see what they finally find," he said of the experiments being conducted by Phoenix.

But in the early going, at least, Phoenix's robotic arm has had difficulty putting the ball in the basket, as a sportscaster might phrase it, and suspense is mounting for Ash.

When the arm scooped up clods and dumped them onto a screen that is designed to break up the Martian surface material into tiny pieces, hardly any tiny pieces broke off the clods and fell into the lander's miniature ovens. On Wednesday, June 11, NASA reported that it finally had filled one of the eight ovens with specks of material, but there was no report yet on an analysis.

The ovens are linked to a mass spectrometer. Their purpose is to slowly heat up specks of material and take measurements necessary to determine the content. "If it's water, it will sit at 0 degrees Celsius while it sublimates from solid to vapor phase," Ash explained.

For a variety of reasons, NASA has a stated goal in Mars exploration to "follow the water." If the intriguing white substrate that is visible in Phoenix photographs is water ice, perhaps exposed because the NASA craft stirred up dusty sediment on the northern Mars plane when it landed, this would be encouraging news to scientists who believe life exists or has existed on the fourth planet from the Sun. Easy access to water at suitable landing sites might also promote the notion that Mars could support a human colony.

To Ash, however, H2O is more than just a molecule essential for life on Mars. Water ice (differentiated from frozen CO2 gas, or dry ice) that is scooped up by the Phoenix robotic arm could spark new interest in a 30-year-old report he wrote while he was a researcher at the Jet Propulsion Laboratory (JPL) in Pasadena, Calif. The report was produced after he and two colleagues were asked to investigate the possibility of making rocket fuel from materials found on the Martian surface. For NASA to manage a return mission from Mars to Earth, carrying samples collected or mined by robots, and also perhaps carrying the first humans to set foot on the planet, the fuel for the return trip more than likely would have to be created on Mars.

Fuel weighs too much to be easily transported from Earth to Mars for the return trip, and, besides, NASA prefers not to have a spacecraft make a 200-day trip to Mars carrying both astronauts or hard-to-replace equipment together with highly volatile rocket fuel.

In their 1978 report, Ash, together with JPL's Warren Dowler and Giulio Varsi, explain how rocket fuel could be produced from the CO2-rich Martian atmosphere and available water. (Ash, R. L., W. L. Dowler and G. Varsi, "Feasibility of Rocket Propellant Production on Mars," Acta Astronautica, Vol. 5, pp. 705-724, 1978.)

The proposed approach came to be known as in situ resource utilization, or ISRU, but it didn't gain much acceptance until NASA published a baseline manned Mars mission design in 1997 that incorporated the researchers' approach. "Still, in situ resource utilization seems always to be just over the horizon for NASA," Ash explained. One reason is the lack of proof that sufficient water could be tapped at sites selected as Mars staging locations.

Ash notes that water in clouds over Mars or in surface samples tested during previous Mars missions is present in very small amounts and could not be exploited for fuel production. On the other hand, big deposits of polar ice are inaccessible. So for his in situ scheme to work, large bands of water ice need to be fairly close to the Mars surface in locations such as the flat plane where Phoenix landed. It could be dug up and heated by solar energy or some other heat source for the rocket fuel production and for other uses at a Mars station.

Phoenix has strung out the suspense. Ash is optimistic about the mission photos showing a white substrate, but admits that it could be salt, not water ice.

"If water ice is present in large quantities, then we will have an excellent argument for initiating a permanent robotic base on the Martian surface that could be built up eventually as a human outpost," Ash wrote in a Phoenix update to his colleagues and students on June 9. He is associate vice president for research and economic development, as well as an eminent scholar and professor of aerospace engineering at ODU.

Ash's update explains how a Sabatier chemical reactor could produce a methane fuel from water and the Martian atmosphere, as well as how a Bosch reactor could produce an oxygen propellant from the same raw materials.

"Liquid methane and oxygen can be stored at temperatures around 125 Kelvin (about minus-225 degrees Fahrenheit), and while this is cold compared to an average Mars surface (the Phoenix landing site has ranged from minus-22 to minus-112 degrees Fahrenheit), it is relatively easy to maintain these two cryogenic liquids in propellant tanks on the Martian surface. Then, you would have the ability to fuel large exploration vehicles at a central base and send them out over large distances."

So when will humans set foot on Mars?

Ash says not any time soon. "There are fewer reasons today than in 1978 to put a human on Mars," he explains. "The risks are just too great to try to win bragging rights by planting a flag on Mars." He said today's technological advances allow for effective exploration and measurements without humans being present.

"In my humble opinion, when we finally send people to Mars, it will be because we cannot afford the eight- to 40-minute communication delays resulting from controlling a large number of robotic exploration machines from Earth. It will be necessary to have humans on site to tele-operate the robotic operations from Mars."