VEGA1 HALLEY FLYBY MAGNETOMETER DATA

On MARCH 6, 1986, AT 7:20:06 UT, the Vega spacecraft passed the nucleus of comet Halley at a distance of 8,890 km with a relative velocity of 78 km/s. The magnetic field experiments MISCHA carried four fluxgate sensors, with three sensors mounted on a boom at the end of the solar panels and the fourth sensor mounted one meter closer. During the cruise phase, the TRASSA-1 mode of the instrument (1 vector/2.5 min) was used. The sensors were switched to the TRASSA-2 mode (1 vector/min) during the flyby which started roughly two days before the encounter. From 3 h before closest approach (CA) until 1 hour after CA, the HS-mode (1 vector/6s) and the DT-mode (1 vector/100ms) was used [DELVAETAL1991].