The Peregrine Ion-Trap Mass Spectrometer (PITMS) after successfully completing tests in a vacuum chamber. The aperture cover (held by the operator) is open in this image; this is the nominal position for measurement. On the Moon, the cover will be opened shortly after landing.
PITMS is a device that will sniff out molecules close to the Moon's surface to chart the composition of the lunar exosphere, the particles buzzing around its surface that don't quite make up an atmosphere.
The Peregrine lander is aiming for a lunar touchdown near the Gruithuisen volcanic domes later this year, on the northern lunar hemisphere. It is the first time that a spacecraft will land this area, and it will give the mass spectrometer a good overview of the exospheric modules in a pristine location.
The PITMS instrument is a collaboration between ESA/ESTEC and NASA's Goddard Space Flight Center, where ESA provides the Exospheric Mass Spectrometer that is at the heart of the PITMS instrument, and Goddard provide structural, mechanical and thermal design elements. The PITMS operations are led by Principal Investigator B. Cohen (NAA GSFC) with support from a NASA/ESA selected science team.