[meteorite-list] NASA Curiosity Rover Detects No Methane on Mars

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 19 Sep 2013 12:10:58 -0700 (PDT)
Message-ID: <201309191910.r8JJAw6V001980_at_zagami.jpl.nasa.gov>

September 19, 2013

Dwayne Brown
Headquarters, Washington
202-358-1726
dwayne.c.brown at nasa.gov

Guy Webster
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6278
guy.webster at jpl.nasa.gov
     
RELEASE 13-288
     
NASA Curiosity Rover Detects No Methane on Mars

Data from NASA's Curiosity rover has revealed the Martian environment lacks
methane. This is a surprise to researchers because previous data reported by
U.S. and international scientists indicated positive detections.

The roving laboratory performed extensive tests to search for traces of
Martian methane. Whether the Martian atmosphere contains traces of the gas
has been a question of high interest for years because methane could be a
potential sign of life, although it also can be produced without biology.

"This important result will help direct our efforts to examine the
possibility of life on Mars," said Michael Meyer, NASA's lead scientist for
Mars exploration. "It reduces the probability of current methane-producing
Martian microbes, but this addresses only one type of microbial metabolism.
As we know, there are many types of terrestrial microbes that don't generate
methane."

Curiosity analyzed samples of the Martian atmosphere for methane six times
from October 2012 through June and detected none. Given the sensitivity of
the instrument used, the Tunable Laser Spectrometer, and not detecting the
gas, scientists calculate the amount of methane in the Martian atmosphere
today must be no more than 1.3 parts per billion, which is about one-sixth as
much as some earlier estimates. Details of the findings appear in the
Thursday edition of Science Express.

"It would have been exciting to find methane, but we have high confidence in
our measurements, and the progress in expanding knowledge is what's really
important," said the report's lead author, Chris Webster of NASA's Jet
Propulsion Laboratory in Pasadena, Calif. "We measured repeatedly from
Martian spring to late summer, but with no detection of methane."

Webster is the lead scientist for spectrometer, which is part of Curiosity's
Sample Analysis at Mars (SAM) laboratory. It can be tuned specifically for
detection of trace methane. The laboratory also can concentrate any methane
to increase the gas' ability to be detected. The rover team will use this
method to check for methane at concentrations well below 1 part per billion.

Methane, the most abundant hydrocarbon in our solar system, has one carbon
atom bound to four hydrogen atoms in each molecule. Previous reports of
localized methane concentrations up to 45 parts per billion on Mars, which
sparked interest in the possibility of a biological source on Mars, were
based on observations from Earth and from orbit around Mars. However, the
measurements from Curiosity are not consistent with such concentrations, even
if the methane had dispersed globally.

"There's no known way for methane to disappear quickly from the atmosphere,"
said one of the paper's co-authors, Sushil Atreya of the University of
Michigan. "Methane is persistent. It would last for hundreds of years in the
Martian atmosphere. Without a way to take it out of the atmosphere quicker,
our measurements indicate there cannot be much methane being put into the
atmosphere by any mechanism, whether biology, geology, or by ultraviolet
degradation of organics delivered by the fall of meteorites or interplanetary
dust particles."

The highest concentration of methane that could be present without being
detected by Curiosity's measurements so far would amount to no more than 10
to 20 tons per year of methane entering the Martian atmosphere, Atreya
estimated. That is about 50 million times less than the rate of methane
entering Earth's atmosphere.

Curiosity landed inside Gale Crater on Mars in August 2012 and is
investigating evidence about habitable environments there. JPL manages the
mission and built the rover for NASA's Science Mission Directorate in
Washington. The rover's Sample Analysis at Mars suite of instruments was
developed at NASA's Goddard Space Flight Center in Greenbelt, Md., with
instrument contributions from Goddard, JPL and the University of Paris in
France.

For more information about the mission, visit:

http://www.nasa.gov/msl

and

http://mars.jpl.nasa.gov/msl

To learn more about the SAM instrument, visit:

http://ssed.gsfc.nasa.gov/sam/index.html

-end-
Received on Thu 19 Sep 2013 03:10:58 PM PDT