MESSENGER Update - November 26, 2003

http://messenger.jhuapl.edu/webcam/annotatedimages/annotated-20031120.html

MESSENGER Mission News         
November 26, 2003
 
Taking Charge
 
In this week's Webcam image MESSENGER engineers install the spare 
flight battery, which will provide power to the spacecraft's systems 
and instruments through the next several months of operational and 
environmental testing at the Applied Physics Laboratory and NASA's 
Goddard Space Flight Center. Until now, the team had been using a 
temporary, external "workhorse" battery to power MESSENGER's onboard 
operations. 
 
The spare battery is fully flight-qualified; the team would be able 
to use it on MESSENGER if something happened to the actual flight 
battery before launch. Both are 20-Ah (ampere hour) common-pressure-
vessel nickel-hydrogen types, consisting of 22 individual cells tied 
together in pairs. The team plans to install the flight battery 
during final prelaunch preparations at Kennedy Space Center/Cape 
Canaveral Air Force Station, Florida, next spring.
 
MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and 
Ranging) is a scientific investigation of the planet Mercury, and 
the first NASA mission designed to orbit the planet closest to the 
Sun. Dr. Sean C. Solomon, of the Carnegie Institution of Washington, 
leads the mission as principal investigator. The Johns Hopkins 
University Applied Physics Laboratory in Laurel, Md., is building 
and will operate the MESSENGER spacecraft and manages the Discovery-
class mission for NASA.