The MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft was successfully launched from Kennedy Space Center in Florida on August 3, 2004. As part of NASA’s Discovery program, MESSENGER will be the first spacecraft to closely observe the planet Mercury since the Mariner 10 flybys of the mid-1970s. MESSENGER has completed its single Earth flyby and two flybys of Venus, and will make three flybys of Mercury prior to orbiting the planet for one Earth-year beginning in March 2011. Dan O’Shaughnessy is the current lead for MESSENGER’s Guidance and Control subsystem. Along with monitoring the spacecraft’s telemetry and attitude, he ensures the accuracy of deep space maneuvers and trajectory correction maneuvers. By continually updating models of the spacecraft dynamics and working to solve “in-flight” problems, the GNC team makes certain that MESSENGER is always pointing in the right direction in order to perform its mission successfully.
I am here at the Applied Physics Laboratory to learn as much as possible about spacecraft design and operations. MESSENGER provides me the perfect opportunity to do this with a real spacecraft. I’ve come to understand the inner workings of MESSENGER, the routines involved in keeping a spacecraft flying, and how problems are solved after a spacecraft has left the Earth. My main contribution is implementing some basic dynamics equations through a Matlab script. The script works backwards from attitude and control information sent back from MESSENGER during a maneuver of interest, and includes a model of solar radiation pressure, to try and come up with an accurate estimate of MESSENGER’s current dynamical properties, such as moment of inertia and center of mass.
Last Modified: Tuesday, 24-Jul-2007 10:10:28 CDT -- this is in International Standard Date and Time Notation