First direct magnetic field measurements of an asteroidal magnetic field: DS1 at Braille

Deep Space 1 (DS1) is the first interplanetary spacecraft (s/c) using ion propulsion and aims at investigating the compatibility of innovative technology with scientific measurements. DS1 performed a successful flyby at the asteroid Braille on July 29th, 1999. This closest‐ever encounter allowed for the first time a direct measurement of an asteroidal magnetic field. The manifold magnetic disturbances caused by the ion propulsion onboard DS1, however, required an elaborate data processing scheme in order to extract the magnetic signature of Braille. Its successful application to the magnetometer data of the asteroid flyby reveals a magnetic moment of 2.1 · 1011Am² for Braille.