Galileo's Main Engine

The 400-N main engine, a crucial part of the Galileo propulsion system provided by the Federal Republic of Germany to NASA, continued its exemplary performance with the successful completion of the critical Jupiter Orbit Insertion (JOI) maneuver on December 7, 1995. The entire Retro-Propulsion Module (RPM) system performed flawlessly during the required 49 minutes of engine firing. This represented the second in-flight use of Galileo's main engine, following a 2-second "wake-up" burn and a 5-minute primary burn in late July 1995. The wake-up burn was executed to check out the flight readiness of the RPM components for the ensuing Orbiter Deflection Maneuver (ODM); the ODM was then performed to divert the orbiter from the probe's Jupiter-entry trajectory. A detailed description of the ODM was reported in Issue 37 of the Messenger (September 1995).

Galileo's successful completion of JOI marked a first in planetary exploration---the first human-made object to achieve orbit about an outer planet. The unique success of this critical maneuver after more than 6 years in space is a true testament to the engineering accomplishments of our German partners Deutsche Agentur für Raumfahrtangelegenheiten (DARA), Deutsche Forschungsanstalt für Luft- und Raumfahrt (DLR), and Daimler Benz Aerospace (DASA), and we offer our most sincere congratulations.

The RPM Unit Leader at JPL is Fritz Krug, who is supported by two RPM Analysts, Klaus-Peter Renner from DLR and Todd Barber of JPL. In attendance at JPL for the JOI were three project representatives from Germany: Dr. Rainer Killinger of DARA, the Project Manager for the German contribution to Galileo; Klaus Bohnhoff of DASA, the RPM Contractor Project Manager; and Helmut Schweig of DASA, the RPM Analyst.

The RPM was manufactured as a single unit that included---in addition to the main engine---twelve 10-N thrusters, four propellant tanks, and two pressurant tanks.

On March 14, 1996, the 400-N engine executed the Perijove Raise Maneuver (PJR), a 24-minute firing to boost the perijove of the first orbit to an acceptable level with respect to radiation tolerance. The 2-year orbital tour trajectory will be guided using the 10-N thrusters, which have seen extensive use during the early Venus-Earth-Earth-Gravity-Assist (VEEGA) portion of the Galileo mission. In summary, the entire RPM system has performed commendably, and the prospects for an exciting tour of Jupiter, its satellites, and magnetosphere remain excellent.