Innovative Explorer mission to interstellar space

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Physics and Astronomy


A mission to interstellar space has been under discussion for over 25 years. Many fundamental scientific questions about the nature of the surrounding galactic medium and its interaction with the solar system can only be answered by in situ measurements that such a mission would provide. The technical difficulties and budgetary and programmatic realities have prevented implementation of previous studies based on the use of a near-Sun perihelion propulsive maneuver, solar sails, and large fission-reactor-powered nuclear electric propulsion systems. We present an alternative approach – the Innovative Interstellar Explorer – based on Radioisotope Electric Propulsion. A high-energy, current-technology launch of the small spacecraft is followed by long-term, lowthrust, continuous acceleration enabled by a kilowatt-class ion thruster powered by Pu-238 Stirling radioisotope generators. We describe the science, payload, and mission and spacecraft design. We also discuss the role such a mission plays in assessing heliospheric “space climate,” knowledge of which is vital for human exploration to Mars and beyond.