סמינר: SATELLITE TOURS AND LOW-THRUST TRAJECTORIES TO THE OUTER PLANETS

Masa Okutsu, Ph.D.

Postdoctoral Researcher
School of Aeronautics and Astronautics, Purdue University

Design strategies are discussed for tours at Jupiter and at Saturn and for low-thrust trajectories to Jupiter via gravity assists from Venus, Earth, and Mars. Saturn-escape trajectories via Titan gravity assist are considered as an option for a contamination-free, end-of-mission scenario for the Cassini spacecraft. A preliminary study shows that the spacecraft can be targeted to impact Jupiter, Uranus, or Neptune or to escape the solar system. Tour design for a Europa Orbiter at Jupiter is also investigated. Because of the possibility of a subsurface ocean, missions to Europa are of great scientific interest. To achieve orbit, the hyperbolic excess speed at Europa is reduced via multiple gravity-assists from the Galilean satellites, while maintaining low radiation dose and acceptable time of flight. Finally, low-thrust trajectories to Jupiter via gravity assists from Venus, Earth, and Mars are analyzed. Trades between time of flight, mass, and hardware specifications are examined. Propellant-optimal trajectories are found for ranges of specific impulse and specific mass that represent present-day technologies (such as an ion thruster with a radioisotope power source) and for future technologies (such as a nuclear-powered magnetoplasmadynamic thruster which may be available in 10 to 15 years).

Biography

Dr. Masa Okutsu received his Ph.D. in December 2006 from Purdue University under the direction of Professor James Longuski. Masa has conducted research on gravity-assist and low-thrust mission design, including such projects as satellite tours at outer planets, low-thrust trajectories to Jupiter, and human missions to Mars. Masa is currently a postdoctoral researcher at Purdue, where he serves as instructor of spacecraft design and as project manager of a team developing virtual reality games for aerospace engineering education.

ההרצאה תתקיים ביום שני כ''ח תשרי תשס''ט (27.10.2008)
שעה 13:30
בנין אוירונוטיקה חדר 241
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