Evidence of life on Mars could come from Martian moon

Jul 04, 2012 by Elizabeth K. Gardner
The image shows the orbits of the Martian moons Phobos and Deimos and the spread of potential particle trajectories from an asteroid impact on Mars. (Purdue University image/courtesy of Loic Chappaz)

(Phys.org) -- A mission to a Martian moon could return with alien life, according to experts at Purdue University, but don't expect the invasion scenario presented by summer blockbusters like "Men in Black 3" or "Prometheus."

"We are talking little green microbes, not little green men," said Jay Melosh, a distinguished professor of earth, atmospheric and planetary sciences and physics and at Purdue. "A sample from the , which is much easier to reach than the Red Planet itself, would almost surely contain Martian material blasted off from large asteroid impacts. If life on exists or existed within the last 10 million years, a mission to Phobos could yield our first evidence of life beyond Earth."

Melosh led a team chosen by NASA's Office to evaluate if a sample from Phobos could contain enough recent material from Mars to include viable Martian organisms. The study was commissioned to prepare for the failed 2011 Russian Phobos-Grunt mission, but there is continued international interest in a Phobos mission, he said. It will likely be a recurring topic as NASA reformulates its .

A Phobos mission was discussed at NASA's Concepts and Approaches for Mars Exploration workshop and a report issued Tuesday stated that the Martian moons are "important destinations that may provide much of the value of human surface exploration at reduced cost and risk."

Melosh collaborated with Kathleen Howell, the Hsu Lo Professor of Aeronautical and Astronautical Engineering, and graduate students Loic Chappaz and Mar Vaquero on the project.

The researchers combined their expertise in impact cratering and orbital mechanics to determine how much material was displaced by particular asteroid impacts and whether individual particles would land on Phobos, the closer of the two Martian moons.

The team concluded that a 200-gram sample scooped from the surface of Phobos could contain, on average, about one-tenth of a milligram of Mars launched in the past 10 million years and 50 billion individual particles from Mars. The same sample could contain as much as 50 milligrams of Mars surface material from the past 3.5 billion years.

"The time frames are important because it is thought that after 10 million years of exposure to the high levels of radiation on Phobos, any biologically active material would be destroyed," Howell said. "Of course older Martian material would still be rich with information, but there would be much less concern about bringing a viable organism back to Earth and necessary quarantine measures."

When an asteroid hits the surface of a planet it ejects a cone-shaped spray of surface material, similar to the splash created when someone does a cannonball into a swimming pool. These massive impacts pulverize the surface material and scatter high-speed fragments. The team calculated that the bulk of the fragments from such a blast on Mars would be particles about one-thousandth of a millimeter in diameter, or 100 times smaller than a grain of sand, but similar in size to terrestrial bacteria.

The team followed the possible paths the tiny particles could take as they were hurtled from the planet's surface through space, examining possible speeds, angles of departure and orbital forces. The team plotted more than 10 million trajectories and evaluated which would intercept Phobos and where they might land on the moon during its eight-hour orbit around Mars.

The probability of a particle landing on Phobos depends primarily on the power of the blast that launched it from the surface, Chappaz said. 

"It is estimated that during the past 10 million years there have been at least four large impact events powerful enough to launch material into space, and we focused on several large craters as possible points of origin," he said. "It turns out that no matter where Phobos is in its orbit, it would have captured material from these powerful impact events."

After the team submitted its report, scientists identified a large, nearly 60-kilometers-in-diameter crater on Mars. The crater, named Mojave, is estimated to be less than 5 million years old, and its existence suggests that there would be an even greater amount of Martian material on Phobos that could contain viable organisms than estimated, Melosh said.

"It is not outside the realm of possibility that a sample could contain a dormant organism that might wake up when exposed to more favorable conditions on Earth," he said. "I participated in a study that found that living microbes can survive launch from impacts on rock, and other studies have shown some microscopic organisms can tolerate a lot of cosmic radiation."

This possibility has been a consideration for some time, and Michael Crichton's "The Andromeda Strain" brought it to public consciousness in 1969. However the movie scenario of a fatal contamination is unlikely, Melosh said.

"Approximately one ton of Martian material lands on Earth every year, " he said. "There is a lot more swapping back and forth of material within our solar system than people realize. In fact, we may owe our existence to life on Mars."

Howell also is optimistic that life is not unique to Earth.

"It's difficult to believe there hasn't been life somewhere out there in the vast expanse of space," Howell said. "The question is if the timeline overlaps with ours enough for us to recognize it. Even if we found no evidence of life in a sample from Phobos, it would not be a definitive answer to the question of whether or not there was life on Mars. There still may have been life that existed too long ago for us to detect it."

Melosh recently presented the team's findings at a joint NASA and European Space Agency meeting in Austria, and Chappaz will present the data at a meeting on July 14 in Mysore, India.

Explore further: Voyager spacecraft might not have reached interstellar space

Provided by Purdue University

3.7 /5 (3 votes)
add to favorites email to friend print save as pdf

Related Stories

Russian craft embarks on voyage to Mars moon (Update)

Nov 08, 2011

A Russian probe on Wednesday set off on a three year return mission to Mars that aims to bring the first sample of a Martian moon back to Earth and re-establish Moscow as a power in planetary exploration. ...

Russia aims for first conquest of Mars

Nov 07, 2011

Russia on Wednesday launches a probe for Mars that aims to collect a chunk of a Martian moon and become Moscow's first successful planetary mission since the collapse of the Soviet Union.

Phobos slips past Jupiter (w/ video)

Jun 17, 2011

(PhysOrg.com) -- Earlier this month, ESA's Mars Express performed a special manoeuvre to observe an unusual alignment of Jupiter and the martian moon Phobos. The impressive images have now been processed into ...

Phobos flyby images (w/ Video)

Mar 15, 2010

Images from the recent flyby of Phobos, on 7 March 2010, are released today. The images show Mars' rocky moon in exquisite detail, with a resolution of just 4.4 metres per pixel. They show the proposed landing ...

Russia Mars probe considered lost: report

Nov 12, 2011

Efforts to resume contact with a Russian space mission to Mars stuck in Earth orbit after launch have failed and the probe must be considered lost, Interfax news agency reported Saturday.

Russia Mars probe may fall to Earth in January

Nov 14, 2011

A Russian probe that was to visit a moon of Mars but is stuck in orbit around the Earth could burn up in the Earth's atmosphere in January, the head of the Russian space agency said Monday.

Recommended for you

Video: A dizzying view of the Earth from space

1 hour ago

We've got vertigo watching this video, but in a good way! This is a sped-up view of Earth from the International Space Station from the Cupola, a wraparound window that is usually used for cargo ship berthings ...

NEOWISE spots a comet that looked like an asteroid

1 hour ago

Comet C/2013 UQ4 (Catalina) has been observed by NASA's Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) spacecraft just one day after passing through its closest approach to the sun. The comet ...

What the UK Space Agency can teach Australia

1 hour ago

Australia has had an active civil space program since 1947 but has much to learn if it is to capture a bigger share of growing billion dollar global space industry. ...

Discover the "X-factor" of NASA's Webb telescope

1 hour ago

NASA's James Webb Space Telescope and Chandra X-ray observatory have something in common: a huge test chamber used to simulate the hazards of space and the distant glow of starlight. Viewers can learn about ...

User comments : 3

Adjust slider to filter visible comments by rank

Display comments: newest first

deatopmg
1 / 5 (1) Jul 05, 2012
Interesting that this obscure and unlikely method to detect life on Mars has been proposed when NASA has, up until this latest Mars mission, failed (avoided?) to send any life detecting instrumentation since one the two Viking missions detected a life like response to an experiment in the '70's, ca. 35!!!!! yrs.

The experiment added a nutrient broth to a soil sample that then released CO2, w/ a diurnal response, for ca. 45 days.
antialias_physorg
not rated yet Jul 05, 2012
Interesting that this obscure and unlikely method to detect life on Mars has been proposed

Because, if you remember, the russians were going to do it last year (but unfortunately their craft never got out of Earth orbit and burned up on reentry in January 2012).
The Phobos-Grunt mission was supposed to return 200-400 grams of material from the Phobos surface. So while the russians were doing their thing it wasn't really sensible to have NASA plan one of their own, was it?
Relations being what they are scientists from around the world would have had access to the data.
Torbjorn_Larsson_OM
1 / 5 (1) Jul 05, 2012
The russians has attempted this a long time. And it is only by recognizing what an effort "Mars Direct" would be that people have started to look more closely what landing on the martian moons would do.

The Viking experiment was, and remains, inconclusive. Which is why NASA _many years ago_ broke it down to look for water (which Viking failed to find; now checked) - look for organics (which Viking failed to do; now ongoing) - assess fossilization/extant life (that Viking wasn't fully tasked to do; a sample return mission goal). It has been a very fruitful approach. Viking not so much, it used wrong ideas on what to find and how to do it.