The OPTIMISM/MAG Mars-96 experiment: magnetic measurements onboard landers and related magnetic cleanliness program

Abstract The paper presented is a comprehensive description of the MARS-96 SAS (small autonomous station) magnetometer experiment. Starting with a detailed discussion of what is known about the magnetic field on and around Mars as well as the Moon and Earth in comparison, the scientific objectives clearly lead to the design goals for a magnetic field instrument to be part of the scientific payload of a Mars lander. The magnetometer is presented in general and partly in more detail e.g. how to achieve a fairly good temperature stability over the expected temperature range of −80°C–+40°C, or with respect to the design of the attitude determination devices. In a final part, a discussion of the magnetic cleanliness of spacecrafts (S/C) in general, and the SAS in detail, is given. As a result it is shown, that despite the reduced Mars-96 magnetic cleanliness programme as for the SASs only, a distortion field of less than 10 nT at the magnetometer's sensor position was achieved. This gives strong confidence for the magnetic field measurements.