Langmuir Probe and Waves instrument on Mars Atmosphere and Volatile EvolutioN mission

To understand how the water was lost at Mars it is critical to understand the atmosphere. One important parameter that is needed and is complicated to model is the electron temperature. At present time most atmospheric models use a fixed temperature profile based on only two in-situ measurements made over 30 years ago by the Viking landers. How important the ion outflow at Mars is for the atmospheric loss depends on how much heating takes place close to the exobase. At Mars the frequencies of the fluctuations in the solar wind can couple directly to the exobase, where such frequencies are close to the heavy ions gyro motion allowing efficient energy transfer from the solar wind to the ions at the exobase. Another part of the puzzle of the atmospheric escape is the ionization rate that is mainly driven by wavelengths in EUV from the sun. Therefore, the newest NASA mission, Mars Atmosphere and Volatile EvolutioN (MAVEN) mission, to be launched in November 2013 and arrive at Mars September 2014, has included a Langmuir Probe and Waves (LPW) instrument which incudes and EUV detector. This instrument measures (1) electron temperature and density via a Langmuir probe; (2) DC and AC electric fields; and (3) the most critical EUV bands of the solar irradiance with a separate detector. This presentation describes the instrument capabilities and the expected impact the data will have on the field.