http://messenger.jhuapl.edu/webcam/annotatedimages/annotated-20031115.html

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.