Design, characteristics and scientific tasks of the LASMA-LR laser ionization mass spectrometer onboard Luna-25 and Luna-27 space missions

Abstract

The laser-ionization time-of-flight mass spectrometer LASMA-LR is part of the scientific payload of the Luna-25 and Luna-27 missions. The instrument is able to perform analysis of elemental and isotopic composition of solid samples (regolith and dust) with high accuracy and high spatial resolution. The principle of the instrument operation consists in complete atomization and ionization of the substance by a laser pulse, separation of ions during their free expansion, depending on their mass and charge, and subsequent registration of the ions time of flight from the sample to the detector. The instrument has small dimensions (130 × 206 × 254 mm), low weight (2.8 kg) and low mean operating power consumption (8 W). The limits of detection for element analysis are at least 50 ppmA (ppm atomic fraction) in one mass spectrum and 5 ppmA at analysis of an accumulation of 100 mass spectra. The scientific data which will be obtained by LASMA-LR can be essential for a wide range of studies, such as the geological characteristics of spacecraft landing sites, analysis of the lunar dust composition, search for rare earth elements, native metals and alloys, determination of the content of chemically bound water in regolith, and others. Achievement of these tasks will contribute to the study of fundamental questions ranging from the formation and evolution history of the Moon to the advancement of a number of applied problems of the Moon exploration and colonization.With the LASMA-LR instrument we have demonstrated that it is possible to provide all these analytical capabilities in a very compact, lightweight and at low power, which lends itself to operational concepts not only for robotic probes landed on the Moon, but also for proposed human spaceflight missions to the Moon and robotic missions to asteroids for the local prospection of mineral resources with a portable device, possibly as equipment carried by astronauts during their surface missions.