Spacecraft Propulsion Utilizing Ponderomotive Forces

A new spacecraft propulsion scheme is proposed which leverages advances in high-energy particle acceleration via laser-plasma interactions. Ponderomotive forces associated with laser wake-fields have demonstrated the potential to accelerate electrons to near-relativistic energies. Different schemes are investigated which may generate efficient propulsion systems for deep-space and manned space missions. Ponderomotive propulsion which leverages its inherent capability to decouple the mass of the power system could revolutionize space travel by providing very high thrust at very high specific impulses. 1.0 Introduction Inherent in grand vision of space exploration is the desire to rapidly and robustly transit between heavenly bodies. This includes both interplanetary and interstellar exploration. Rapid transit is, in this context, akin to rapid communication: the ability to investigate ongoing phenomena and to deliver not only information but material supply to support ongoing exploration and commercialization. Realization of this vision relies to a large extent on significant developments in propulsion, i.e., power conversion to spacecraft motion. The following report summarizes the Phase I investigation of a new propulsion system that leverages recent significant advancements in power conversion. Several propulsion concepts are being developed to significantly enhance near-term capabilities. The most mature of these is solar electric propulsion (SEP). With specific impulses in the range of 2000 s to 10,000 s, it enables many solar system exploration missions which either deliver a larger payload or reduce mission time relative to chemical propulsion systems. Incorporation of nuclear (fission-based) electric power yielding nuclear electric propulsion (NEP) or nuclear thermal propulsion (NTP) will enhance this capability but not radically alter it. However, state of the art propulsion systems are inherently mass-limited. That is, either the mass of the propellant or the mass of the electrical power supply determines the size of the spacecraft delivered to its objective and/or the time required to deliver the spacecraft. This limitation precludes rapid transits and restricts exploration to infrequent, large-scale missions which are geared to compromise between various mission goals. The performance limits of the technology readiness, preclude the grander vision of exploration. 1.1 Advanced Propulsion Concepts Several concepts have been explored in recent years which have the promise to overcome the limitations of NEP, NTP, and advanced chemical propulsion for deep space/interstellar applications. Figure 1 summarizes the findings of a recent investigation of several options. 1 Of those identified as best candidates, the Laser Light Sail concept warrants further discussion in the context of the present investigation. Laser Light sails are preferable to Solar Sails for deep space applications (the most demanding of which is used as a filter in the figure), because it enables a much higher photon density and therefore thrust. A transmitter with 100 km diameter optics