NASA MESSENGER Mission News March 19, 2004

This week’s Webcam image shows MESSENGER in Florida undergoing final
testing and preparation for launch in May. The spacecraft’s solar
panels, removed before last week’s shipment to the Astrotech Space
Operations facility, can be seen on special stands awaiting
reinstallation.

The distinctive, temporary red covers have been removed from the two
antenna assemblies, allowing an excellent view of the actual antenna
systems. Shown in this image is the back antenna assembly; each
assembly is actually four antennas. While at Mercury the low-gain
antenna will be used only for spacecraft-to-Earth (downlink)
communication at low data rates, while the phased array antennas
will provide downlink capability at higher data rates (averaging 9
kilobits per second). The fanbeam actually serves as two antennas,
providing both uplink and downlink at moderate data rates (523 bits
per second, for downlink).

Over the course of the Mercury orbital mission MESSENGER should
return at least 78 gigabits of compressed science data, enabling
scientists to unravel the origin and evolution of this mysterious
planet.

Remaining tasks before launch include final alignment of spacecraft
components and scientific instruments, fueling, spin balancing and
mating to the Delta II rocket’s third stage.