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 p ropulsion and aims at investigating the compatibility of innovative technol ogy with scientific measurements. DS1 performed a successful flyby at the a steroid Braille on July 29th, 1999. This closest-ever encounter allowed for the first time a direct measurement of an asteroidal magnetic field. The m anifold magnetic disturbances caused by the ion propulsion onboard DS1, how ever, required an elaborate data processing scheme in order to extract the magnetic signature of Braille. Its successful application to the magnetomet er data of the asteroid flyby reveals a magnetic moment of 2.1 . 10(11) Am- 2 for Braille.