MET comprises a scanning LIDAR, a temperature (T) sensor, and a pressure (P) sensor. MET will provide data for characterizing Mars' present climate and weather processes at the landing site. The LIDAR provides data on the Martian PBL depth; the location, structure, and optical properties of clouds, fogs, and dust plumes within the PBL; and some wind data. The structure and evolution of the Martian PBL is key to understanding surface atmosphere interactions, particularly the exchange of volatiles. The LIDAR can probe the Martian atmosphere up to 20 km altitude. Data obtained from this height will complement the data obtained by MET's collocated pressure and temperature sensors. LIDAR observations of the formation, duration, and movement of clouds, fog, and dust plumes will improve the modeling of atmospheric processes.

MET LIDAR can pan and tilt, allowing it to point in various directions. The requirement for MET location on the deck ensures that the LIDAR has a clear field of view of at least 100 mrad about the beam axis. Temperature will be measured with thin wire thermocouples, a technology that also has substantial Martian flight heritage. MET thermocouples will be mounted on a polyamide frame that provides electrical insulation, low thermal expansion, strength, and rigidity. The thermocouples will have a small diameter (0.75 µm) to reduce frame conduction, velocity errors, and radiative errors. Chromel constantan thermocouples (Type E) with triple redundant, insulated, gold-plated junctions reduce thermal emissivity.

MET pressure sensor is a Tavis P4, a device similar to the successful sensors used by the Viking and Mars Pathfinder landers. The sensor's analog output will be converted to two digital pressure scales. One scale, ranging from 0 to 14 h Pa, will allow a zero-setting verification during cruise. A second nominal pressure scale, ranging from 9 to 14 h Pa, will maximize the pressure resolution once Phoenix is on the surface. The Tavis P4 measurement accuracy is ±9 Pa. lander electronics function as a backup software system test laboratory (STL). Special test cells for TEGA and MECA will test sample delivery.