This report presents a preliminary design for an unmanned probe to Alpha Centauri with a planned launch early in the 21st century. This mission was based upon a requirement stated in the report by the National Commission on Space, Pioneering the Space Frontier. The probe would be assembled at the space
station and take approximately 100 years to reach the nearest star. Several technologies must be developed in order for this mission to be possible. A pulsed fusion microexplosion drive with 1,000,000 seconds of specific impulse is the primary enabling technology. A large, long-life fission reactor with 300 kilowatts power output is also required. Communications
lasers would use a 0.532 micron wavelength since there is minimal power output by the stars in that frequency band. A laser with an input power of 250 kilowatts would allow for a data rate of 1000 bits per second at maximum range. There are three types of information to be gathered by the probe:
properties of the interstellar medium, characteristics of the three-star Alpha Centauri system, and astrometry (finding distances to stars using parallax measurements).
