Featured Research

from universities, journals, and other organizations

Curiosity shakes, bakes, and tastes Mars with SAM

Date:
December 3, 2012
Source:
NASA/Goddard Space Flight Center
Summary:
NASA's Curiosity rover analyzed its first solid sample of Mars in November with a variety of instruments, including the Sample Analysis at Mars instrument suite.

SAM's three instruments are visible in this view taken before installation of its side panels: the tunable laser spectrometer (TLS) at lower left, the quadrupole mass spectrometer (QMS) at upper right, and the gas chromatograph (GC) at lower right. SAM's solid sample inlet tubes (SSIT), visible at top right, are the routes by which Curiosity's robotic arm will deliver samples of soil and powdered rock for analysis.
Credit: NASA

NASA's Curiosity rover analyzed its first solid sample of Mars in Nov. with a variety of instruments, including the Sample Analysis at Mars (SAM) instrument suite. Developed at NASA's Goddard Space Flight Center in Greenbelt, Md., SAM is a portable chemistry lab tucked inside the Curiosity rover. SAM examines the chemistry of samples it ingests, checking particularly for chemistry relevant to whether an environment can support or could have supported life.

Related Articles


The sample of Martian soil came from the patch of windblown material called "Rocknest," which had provided a sample previously for mineralogical analysis by Curiosity's Chemistry and Mineralogy (CheMin) instrument. CheMin also received a new sample from the same Rocknest scoop that fed SAM. SAM has previously analyzed samples of the Martian atmosphere.

SAM can get a solid sample of Mars from either a drill or a scoop attached to the end of Curiosity's robotic arm. Since Rocknest is essentially a pile of loose soil, the scoop was used this time.

"This is the first time we've analyzed a solid sample using all three instruments that comprise SAM," said Paul Mahaffy, SAM Principal Investigator at NASA Goddard. "We also cleaned Curiosity's sample manipulation system and successfully tested our ability to move the sample from the manipulation system through the instrument suite."

A complex choreography was required to get the sample inside SAM for analysis, according to Mahaffy. First, since the scoop might still have had contamination from Earth, the first three scoops were shaken, run through a sieve, then dumped right back on the surface with the idea that they would carry away any contaminants with them. A sieved portion of the fourth scoop -- just a few thousandths of a gram -- was then delivered to SAM. A cover that protects SAM from accidentally ingesting windblown material was opened, and Curiosity's arm positioned the sample over SAM's inlet funnels. Before the sample was dropped, SAM turned on its inlet funnel vibrators, which move the sample into a tiny quartz cup. After the sample dropped, the vibrator was turned off, the cover was closed, and the cup, which is on a carousel holding 74 sample cups, was lowered and moved to one of two ovens.

After the sample was baked to release its gases, SAM's three instruments "digested" them and gave Curiosity its first "taste" of Mars. A basic three-step process will be used to analyze future samples as well:

Separate the molecules:

Gas from the sample first travels to the Gas Chromatograph (GC) instrument. The purpose of this instrument is to sort out all the different molecules in the sample, and tell how much of each kind there is. It accomplishes this by using a stream of helium gas to push the sample down a long, narrow tube (which is wound into a coil to save space). Helium is used because it is inert, meaning it won't react with and change any of the sample molecules. The inside of the tube is coated with a thin film. As molecules travel through the tube, they stick for a bit on the film, and the heavier the molecule, the longer it sticks. Thus, the lighter molecules emerge from the tube first, followed by the middleweight molecules, with the heaviest molecules bringing up the rear.

Identify the molecules:

Since molecules of different weights emerge from the tube of the gas chromatograph at different times, the GC can send groups of different weights, one at a time, to SAM's next instrument, which will determine exactly what kind of molecule makes up each of the groups. This is the Quadrupole Mass Spectrometer (QMS) instrument. It fires high-speed electrons at the molecules, breaking them up into fragments and giving the molecules and their fragments an electric charge. These molecules and their fragments with an electric charge can be moved by electric fields. The QMS uses both direct current and alternating current fields to sort the electrically charged molecules and fragments based on their weight (mass). Molecules and fragments of different mass are counted by a detector at different times to generate a mass spectrum, which is a pattern that uniquely identifies molecules.

Identify the volatiles and determine the isotopes:

After the QMS identifies the molecules, the sample is directed into the Tunable Laser Spectrometer (TLS), which can identify and analyze certain volatile molecules, like methane and carbon dioxide. The sample enters a chamber with precisely positioned mirrors at both ends. A laser is fired through a tiny hole in one of the mirrors. As the laser light bounces between the mirrors, it illuminates the sample. Different molecules will absorb certain colors (frequencies) of light, so the TLS identifies the molecules by which colors of the laser are blocked (since the laser is tunable, it can be adjusted to shine in a range of colors).

The TLS can also identify isotopes the same way. Isotopes are versions of an element that are a little bit heavier because their nucleus contains more neutrons. For example, carbon 13 is an atom of carbon with an extra neutron, so it is a heavier version of the more common carbon 12. Occasionally, a carbon 13 will take the place of a carbon 12 in an organic molecule. This is important since life prefers to use the lighter isotopes, because chemical reactions with them require less energy. So if we measure the isotopes of carbon in a material and discover that there is more light carbon relative to heavy carbon than would be found randomly, we might guess that we are seeing the effects of life.

Finally, since volatile molecules are found in the atmosphere as well as in soil and rock, samples of the Martian air can be sent directly to the TLS without going through SAM's other instruments.

SAM was developed at NASA Goddard, but with significant elements provided by industry, university, and NASA partners. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Curiosity/Mars Science Laboratory Project for NASA's Science Mission Directorate, Washington. JPL designed and built the rover.

For more information about SAM, refer to the "SAM I am" site at: http://ssed.gsfc.nasa.gov/sam/samiam.html

For more information about the Curiosity rover, visit: http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl


Story Source:

The above story is based on materials provided by NASA/Goddard Space Flight Center. Note: Materials may be edited for content and length.


Cite This Page:

NASA/Goddard Space Flight Center. "Curiosity shakes, bakes, and tastes Mars with SAM." ScienceDaily. ScienceDaily, 3 December 2012. <www.sciencedaily.com/releases/2012/12/121203145948.htm>.
NASA/Goddard Space Flight Center. (2012, December 3). Curiosity shakes, bakes, and tastes Mars with SAM. ScienceDaily. Retrieved December 22, 2014 from www.sciencedaily.com/releases/2012/12/121203145948.htm
NASA/Goddard Space Flight Center. "Curiosity shakes, bakes, and tastes Mars with SAM." ScienceDaily. www.sciencedaily.com/releases/2012/12/121203145948.htm (accessed December 22, 2014).

Share This


More From ScienceDaily



More Space & Time News

Monday, December 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

NASA Prepares for Next Phase of Hubble Successor

NASA Prepares for Next Phase of Hubble Successor

Reuters - Innovations Video Online (Dec. 22, 2014) Scientists and engineers prepare for the next phase of the James Webb Space Telescope, the scientific successor to the Hubble. Nathan Frandino reports. Video provided by Reuters
Powered by NewsLook.com
Spokesman: 'NORAD Ready to Track Santa'

Spokesman: 'NORAD Ready to Track Santa'

AP (Dec. 19, 2014) Pentagon spokesman Rear Adm. John Kirby said that NORAD is ready to track Santa Claus as he delivers gifts next week. Speaking tongue-in-cheek, he said if Santa drops anything off his sleigh, "we've got destroyers out there to pick them up." (Dec. 19) Video provided by AP
Powered by NewsLook.com
NASA's Planet-Finding Kepler Mission Isn't Over After All

NASA's Planet-Finding Kepler Mission Isn't Over After All

Newsy (Dec. 18, 2014) More than a year after NASA declared the Kepler spacecraft broken beyond repair, scientists have figured out how to continue getting useful data. Video provided by Newsy
Powered by NewsLook.com
Rover Finds More Clues About Possible Life On Mars

Rover Finds More Clues About Possible Life On Mars

Newsy (Dec. 17, 2014) NASA's Curiosity rover detected methane on Mars and organic compounds on the surface, but it doesn't quite prove there was life ... yet. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins