Source: MESSENGER Mission
The MESSENGER Magnetometer (MAG) is mounted behind the
spacecraft at the end of a 3.6-m-long boom to ensure that the
instrument is well-separated from fields created by the spacecraft
electronics and moving parts.Image credit: NASA/Messenger.
MESSENGER carries a sensitive Magnetometer that measures the vector magnetic field at the location of the spacecraft. The mission is now trying to map Mercury's magnetic field with an accuracy never achieved before. (read more)