This graphic shows tenfold spiking in the abundance of methane in the Martian atmosphere surrounding NASA's Curiosity Mars rover, as detected by a series of measurements made with the Tunable Laser Spectrometer (TLS) instrument in the rover's Sample Analysis at Mars (SAM) laboratory suite.
The graph covers a span of time from August 2012 to September 2014, labeled on the horizontal axis by the number of sols, or Martian days, since the rover's landing on Mars -- sols 1 through 750. The TLS measurements are indicated by small black squares on the graph, each with a vertical bar representing the margin of uncertainty in that sol's measurement. The measurements cover a 20-month span. Methane concentration in the Martian atmosphere samples climbed to several parts per billion by volume (ppbv, meaning several methane molecules per billion molecules of Martian atmosphere) during a short portion of that period. It averaged about 7 ppbv in those measurements. Both before and after the spike, the measured concentration was at or below about 1 ppbv, averaging 0.7 ppbv.
The TLS technology from Curiosity is being tested for use on Earth as utility-company safety equipment to check for leaks in pipelines carrying natural gas. Methane is a major component of natural gas.
NASA's Mars Science Laboratory Project is using Curiosity in Mars' Gale Crater to assess ancient habitable environments and major changes in Martian environmental conditions. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, built the rover and manages the project for NASA's Science Mission Directorate, Washington. JPL developed and built the TLS. NASA's Goddard Space Flight Center, Greenbelt, Maryland, built and operates SAM.