Posted: Mon, Nov 5, 2012, 6:28 AM ET (1128 GMT)

Scientists working on NASA's Curiosity Mars rover said Friday that initial measurements of the Martian atmosphere failed to turn up any evidence of methane, a constituent detected in some previous observations that could be linked to life. a laser spectrometer on Curiosity's Sample Analysis at Mars instrument measured the composition of the atmosphere at the Gale Crater landing site, putting an upper limit of just a few parts per billion on any methane in the atmosphere there. Methane, which has been seen in some previous observations of the Martian atmosphere, is of interest since its lifetime in the atmosphere would be very short, implying it must have been produced recently. Methane can be produced by lifeforms, or through geological activity. Additional measurements are planned throughout the rover's multiyear mission to look for any changes in the atmosphere's composition and to improve the accuracy of those measurements.