MESSENGER Status Report
April 18 ,2005

The mission operations and spacecraft teams continue to check out MESSENGER's science payload - and prepare for additional instrument operations in the weeks ahead.

The team checked and commissioned the Energetic Particle and Plasma Spectrometer (EPPS) instrument over the past week. On April 8 they wrapped up a two-day look at the EPPS Fast Imaging Plasma Spectrometer (FIPS) element, during which they carefully and gradually turned it up to its highest operating voltage. Then the team moved on to a similar test with the EPPS Energetic Particle Spectrometer component, ending it successfully on April 13. The X-Ray Spectrometer underwent a full functional test on April 14.

FIPS observed the solar wind for an hour on April 15 while spacecraft operators watched MESSENGER's power levels and temperatures around the propellant tanks and rear antenna. Overall the spacecraft is in good health and operating normally.

Visit for additional information on the FIPS solar wind observations.

This month the team also plans to check on the Neutron Spectrometer component of the Gamma-Ray and Neutron Spectrometer instrument, as well as Mercury Atmospheric and Surface Composition Spectrometer.

Stat Corner: MESSENGER is about 85.9 million miles (138.2 million kilometers) from the Sun and 23.1 million miles (37.3 million kilometers) from Earth. At that distance, a signal from Earth reaches the spacecraft in 2 minutes, 4 seconds. The spacecraft is moving around the Sun at 71,869 miles (115,662 kilometers) per hour. MESSENGER's onboard computers have executed 37,887 commands from mission operators since launch on Aug 3, 2004.