MESSENGER Update - November 26, 2003

http://messenger.jhuapl.edu/webcam/a...-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.