Project Forward – Beamed Propulsion
Project Forward, run by Dr. Jim Benford, is a study performed by members of Icarus Interstellar and affiliated organizations with expertise in the field of beamed propulsion. The study will involve: 1. Analyzing past concepts (Forward, Landis, Frisbee, Matloff) to see if they are off-optimal, in terms of the recent cost-optimized model, so can be improved. Then quantify such improved sail system concepts. 2. Exploring properties of materials that are being used for solar sails or have been suggested for beam-powered sails to determine their practicality. In particular, studying their properties in several domains of EM (microwave, millimeter wave, laser) to find out what accelerations they are limited to due to heating in the beam. 3. Quantifying an alternate use of sails-deceleration of sail probes from a fusion-powered starship as it approaches stellar systems.
Beam-Driven Sail Principles: Laser and microwave propelled sails are a new class of spacecraft that uses photon acceleration. Its key virtue is that the propelling beam stays behind, on Earth, but more likely in space. The beam accelerates the sail and its payload to high speed. The ‘beamer’ is reusable, so can accelerate many sails using electrical energy. Like 19th-century railroads, once the rails are built, the train is a small additional cost. It is the only method of interstellar flight that has no physics issues. Indeed, laboratory demonstrations of basic features of beam-driven propulsion have been completed in the last decade (primarily in the microwave). It offers much lower cost probes after a substantial initial investment in the infrastructure. Recently, beam-driven sail flights have demonstrated the basic features of the beam-driven propulsion. This work was enabled by invention of strong, light carbon materials, which operate at high temperatures to allow liftoff under one earth gravity.
Outcome or deliverable: Basically a set of reports, of peer reviewed quality, detailing the major systems necessary for the launch of an interstellar probe powered by beamed propulsion. They’ll be published in JBIS or other appropriate journal. We’ll generate articles for popular science media, for example Discovery, Space News, podcasts and other popular social media tools. In addition, there should be a minimum of two conference presentations per year by major contributors to the study.
More widely, we can then compare with other candidate interstellar probe concepts employing a variety of propulsion methods, principally the nuclear path.
Schedule: Two years, starting Jan 1, 2012, concluding Dec 31, 2013
Note about Robert Forward:
Robert L. Forward passed away ten years ago. Everyone who knew Bob was inspired by him. He used physics like a sculptor uses a chisel, shaping fascinating ideas and possibilities.
Most importantly for this Project which is named for him, he pioneered the idea of driving sails with beams-—laser or microwave—with a savvy eye cocked toward the truly grand goal of interstellar travel. His two-stage and three-stage interstellar sail vehicles, and his ideas for harnessing light and microwaves, made interstellar flight seem realizable. For the first time.
He knew his physics, but refused to be blinkered by its conventional wisdom. His best summary work is Indistinguishable From Magic. He was playful with ideas and wasn’t constrained by formality. A title that I like is “Laser Weapon Target Practice with Gee-Whiz Targets”.
Beyond these areas, any of which could make a full career, he also wrote novels “about ideas I can’t get into the physics journals”. Life on a neutron star. Two planets orbiting so close they shared an atmosphere. Life forming at near absolute zero. Bob made it all seem quite possible.
He did live to see sails fly on beams. And he knew that realizations of his beam/sail propulsion concepts are starting to come true.
The best memorial we can give him is to keep moving—forward, of course.