This image captures the MESSENGER team carrying out a critical test to measure the magnetic field from the spacecraft. Over the past two years, the MESSENGER Magnetometer team measured all of the magnetic components used in the spacecraft and added up these contributions to estimate MESSENGER's total magnetic field. The team then figured out what magnets were needed and where to put them on the spacecraft to cancel out its overall magnetic field.
To make sure this "magnetic balancing" was done right, on Nov. 28, engineers lifted the spacecraft off its rollover fixture with four heavy-duty straps, suspended it from the crane in the high-bay area and pulled on it slightly using a nylon rope "leash." After releasing the rope the spacecraft swung in a gentle pendulum motion that took about 5 seconds for each back-and-forth swing. Tripod-mounted magnetometers placed around the spacecraft accurately measured MESSENGER's magnetic field as it moved from side to side.
(Click here for large
time-lapse movies of the test)
The test showed that the balance magnets were
chosen properly and mounted correctly - so that the spacecraft
is magnetically clean. This ensures that once MESSENGER is in
orbit around Mercury, the Magnetometer will detect only the natural
magnetic field of the planet.
Last updated: December 5, 2003