Since the beginning of spaceflight, humans have accomplished wonderful feats of exploration and showcased their drive to understand the universe.
Yet, in those 60 years, only one spacecraft, Voyager 1 (launched in 1977) has left the solar system. As remarkable as this is, humans will never reach even the nearest stars with out current propulsion technology. Instead, radically new strategies involving the technology already available must be used.
We propose a roadmap to a program that will lead to sending relativistic probes to the nearest stars.
To do so requires a fundamental change in our thinking of both propulsion and our definition of what a spacecraft is. In addition to larger spacecrafts capable of human transportation, we consider “wafer sats”, wafer-scale systems weighing no more than a gram. The wafer sats would include integrated optical communications, optical systems, and sensors. These crafts, combined with directed energy propulsion, could be capable of speeds greater than 0.25 c.
This program has applications for planetary defense, SETI and Kepler missions.