MESSENGER Mission News November 19, 2003

Test Fire

Nov. 15-17 was another busy weekend for the MESSENGER team: From 5
a.m. Saturday through 5 p.m. Monday, engineers checked out the
spacecraft’s subsystems and interfaces during a full-up functional
test.

In this week’s image the team tests MESSENGER’s propulsion system,
using pure nitrogen gas instead of actual volatile propellants. The
propulsion ground-test console controls and measures the flow of
nitrogen to each thruster and valve on the spacecraft. The test
exercised MESSENGER’s large bipropellant thruster, 16 small
hydrazine thrusters and the 34 associated thruster valves. Engineers
made sure the torque commands from the Guidance and Control system
software moved through the spacecraft’s electronics to the proper
thruster. All tests were normal and the propulsion system checked
out as expected.

The team will use this same console to “leak check” the propulsion
system before actual propellant is loaded onto the spacecraft.