Messenger Mission News January 30, 2004

MESSENGER Roast

The MESSENGER spacecraft is now in a thermal vacuum test chamber at
the Goddard Space Flight Center, proving its ability to weather the
extreme environment it will encounter at Mercury.

In the chamber, the spacecraft is subjected to vacuum conditions
(all the air is pumped out) and a wide range of hot and cold
temperatures. MESSENGER was sealed off in the four-story chamber
late last week; over the past few days a large panel of heating rods
has been roasting MESSENGER’s ceramic-fabric sunshade to
temperatures above 350 degrees Celsius (662 Fahrenheit). The team
doesn’t expect the sunshade to get this hot during the mission, but
they do want to make sure there is plenty of margin to avoid any
surprises down the road.

In this week’s image, snapped by the Webcam on Jan. 20, an engineer
installs a few of the 50 thermocouples to the sunshade before the
thermal vacuum tests. Thermocouples are small temperature sensors
made by joining two different metals, giving the engineers exact
temperature readings from key spots on the sunshade. The coils are
connecting wires for the thermocouples, awaiting installation to a
data-collection computer.