ST7
Full Name: Space Technology 7
Phase: Development
Launch Date: December 01, 2009
Mission Project Home Page: http://nmp.jpl.nasa.gov/st7/
Space Technology 7's (ST7) Disturbance Reduction System (DRS) will fly onboard the European Space Agency's (ESA) LISA Pathfinder, formerly called SMART-2, in late 2009 or 2010. The spacecraft will be launched in an Earth-escape trajectory and then delivered to its predetermined orbit by the propulsion module, which is supplied with power and driving signals by the spacecraft through an umbilical connection.
NASA's New Millennium Program (NMP) provides a critical bridge for researchers and scientists to check out high-risk technologies and concepts in space, an environment that can't be replicated in Earth laboratories. Following NMP's objectives, Space Technology 7 (ST7) will flight test the Disturbance Reduction System (DRS), demonstrating that a solid body can float freely in space completely undisturbed. The DRS enhanced position measurement and control technologies will then be applied to follow-on missions well into the 21st century. The Laser Interferometer Space Antenna (LISA), a gravitational-wave observatory, will be the first of such missions.
The Disturbance Reduction System uses the sensor information supplied by the LISA Technology Package (LTP), which is part of ESA's LISA Pathfinder spacecraft. The LPT is based on the concept of freely floating test masses contained within a spacecraft that shields the test masses from external forces. Ideally, the test masses will follow a trajectory determined only by the local gravitational field. The spacecraft position must be continuously adjusted to stay centered about the test masses. In this way, the spacecraft essentially flies in formation with the test masses. The ST7 DRS, then, consists of clusters of micronewton thrusters and drag-free control software residing on a dedicated computer. The software uses sensor information from the LTP to control the thrusters as actuators, and thus keep the test masses totally isolated from external forces.