Sample Analysis at Mars

Photo: MARS RoverIn 2011, NASA will launch the Mars Science Laboratory (MSL), a large, sophisticated rover that will for the first time, make many of Mars’ most intriguing regions viable destinations for investigation. MSL will analyze dozens of samples, scooped from the soil and cored from rocks, as it explores a far greater range than any previous Mars rover. Essentially a robotic laboratory, MSL will carry the most advanced payload of scientific instruments ever used on Mars’ surface, a payload more than 10 times as massive as those of earlier Mars rovers. MSL’s mission is to investigate the past and present potential of Mars to support microbial life.

MSL is about twice as long (about 9 feet) and four times as heavy as NASA’s previous Mars Exploration rovers. It will carry equipment to gather samples of rocks and soil, crush them, and then distribute them to onboard test chambers inside MSL’s analytical instruments. One of the most critical of these instruments, the Sample Analysis at Mars instrument suite (SAM), carries electronics designed and built by the Space Physics Research Laboratory at the University of Michigan.

SAM at a Glance

Description: SAM Illustration

Sample Analysis at Mars

The Sample Analysis at Mars instrument suite will weigh about 83 pounds (38 kilograms) and make up about half the science payload of the Mars Science Laboratory mission. It is a suite of three instruments that will search for carbon-based compounds associated with life. Image credit: NASA/JPL-Caltech

Sample Analysis at Mars (SAM) is a suite of instruments provided by NASA’s Goddard Space Flight Center for the Mars Science Laboratory. SAM comprises a gas chromatograph, a quadrupole mass spectrometer, and a tunable laser spectrometer, with the combined capabilities to identify a wide range of organic (carbon-containing) compounds and to determine the isotopic ratios of key elements. (Isotope ratios are clues to understanding the history of Mars’ atmosphere and water.) SAM will also look for and measure the abundances of light elements, such as hydrogen, oxygen, and nitrogen, typically associated with life. Their relative abundances will be an essential piece of information for evaluating whether Mars can support life now, or could have supported life in the past. (Project website:


Photo: The Mars Science Laboratory (MSL) is planned to launch in late 2011 from Cape Canaveral Air Force Station, Florida.The Mars Science Laboratory (MSL) is planned to launch in late 2011 from Cape Canaveral Air Force Station, Florida.


At present, the entire flight system is undergoing assembly and testing at the Jet Propulsion Laboratory.


As part of NASA’s Mars Exploration Program, the Mars Science Laboratory will expand upon the work of Spirit and Opportunity, the twin Mars Exploration rovers currently on Mars. The anticipated mobility range of MSL is approximately 12 miles and the mission is expected to last at least two Earth years (about one Mars year).

Measurement Objectives

Photo: Measurement ObjectivesThe Mars Science Laboratory will conduct investigations of Mars’ geology in order to assess whether the landing site ever had or still has the potential to support microbial life. The SAM instrument suite will contribute to the mission by providing atmospheric, ground and underground in-situ chemical and isotopic analysis. In order to assess potential habitability, SAM will inventory carbon compounds and detect molecules related to terrestrial life.

Photo: SAM Measurement ObjectivesSAM will also investigate the water-shaped geochemical conditions and processes at Mars, determining the spatial distribution and chemical states of key light elements as well as analyzing the volatiles released from minerals that trace aqueous and geological processes. Because past habitability conditions may have been different than those on Mars today, SAM will examine oxidation chemistry and impact on organic molecules, and quantify isotopic signatures of planetary evolution. This data will greatly contribute to our knowledge of the history of Mars’ atmosphere, water, and geology.


The Space Physics Research Laboratory, continuing a long tradition of joint developments with the Goddard Space Flight Center and Battel Engineering, developed and delivered several key electronics subsystems for the SAM instrument, including:

  • Photo: SAMSThe Command and Data Handling Module (SPRL lead) – performs the instrument’s control and data processing functions, and manages the command and telemetry interface between SAM and the MSL rover
  • The Low voltage Power Supply Module (Battel lead) – provides 240W of conditioned power for all of the SAM instrument subsystems
  • The Valve and Heater Module (Battel lead) – controls the state of 53 valves and 60 independent heaters throughout the instrument
  • The Filament and Bias Module (Battel lead) – provides electrode bias voltages and filament control for the Quadrupole Mass Spectrometer
  • The High voltage module (Battel lead) – provides high voltages for the Quadrupole Mass Spectrometer’s electron multiplier detector
  • The Pyrolysis and Temperature module (Battel lead) – provides precision control of the sample pyrolysis ovens, getters, and gas chromatograph column heaters. It also monitors 63 temperature transducers, located throughout the instrument
  • The Power distribution Module (SPRL lead) – expands the switching capability of the Low Voltage Power Supply for eight additional heater circuits, totaling 10A
  • The Rover Simulators (SPRL lead) – allow independent, pre-delivery operation and test of SAM subsystems, and the integrated SAM instrument, prior to integration with the MSL rover

SPRL also provided flight software test support, RF oscillator design and test support, and systems engineering support to the SAM team for overall instrument design and test.


Photo: SAMSAM team members come not only from Goddard, JPL, and other NASA centers, but also from industry, and universities in the United States and from other countries including France and Mexico.

Charles Edmonson – Project Director