MESSENGER's Power Play
11 Aug 2003
(Source: Johns Hopkins University Applied Physics Laboratory)
MESSENGER Mission News
August 11, 2003
A Powerful Move Forward
MESSENGER's propulsion system is now in place and has passed critical tests as work moves forward on spacecraft assembly. See this week's annotated Webcam image at http://messenger.jhuapl.edu/annotated-20030730.html .
The MESSENGER spacecraft is starting to come alive. Much of the propulsion system has now been integrated and tested. Since the spacecraft is not complete, some components are simulated using special electronics test equipment that allows full up testing of newly installed hardware. Here an engineer can be seen working on the Power Distribution Unit (PDU) -- see May 15 image -- during the propulsion system checkout.
Time-lapse sequences show how engineers can turn the spacecraft through 360 degrees of rotation with the Turnover Fixture and spin the spacecraft on its z-axis by turning the Rotisserie Hand Crank. In this orientation many key components of the spacecraft are visible. The digital Sun Sensor (one of six) plays a critical role ensuring that the spacecraft does not turn the Sunshade away from the Sun. The Solar Array Drive Electronics work to keep the solar panels in the correct orientation to balance the need for power and the temperature of the surface of the panel. The Integrated Electronics Module is one of two main computer processors that control all functions of the spacecraft.