Beam reception and power conversion remain unsolved

Develop a practical, high-specific-power method for a spacecraft to receive a long-range relativistic electron beam and convert its energy into usable propulsion or onboard power without excessive thermal loading, enabling beam-driven acceleration to interstellar-relevant velocities.

Background

The proposed beaming architecture can, in principle, deliver gigawatt-scale power over hundreds of AU. However, the spacecraft must receive and convert that beam power. Pure electromagnetic reflection (e.g., a magnetic sail) avoids structural heating but is power-inefficient for acceleration to ~0.1–0.2c and becomes challenging at high electron energies due to magnetic rigidity and synchrotron losses.

Direct non-thermal conversion to rocket exhaust is attractive but requires near-lossless coupling of beam energy into propellant/plasma with minimal structural heat deposition—capabilities that are not yet demonstrated. Consequently, the receiver and its conversion method are currently the key missing elements.