Physicist and science-fiction author Robert Lull Forward died on 21 September 2002 in Seattle, Washington, from brain cancer. A leader in gravitational radiation astronomy and advanced space propulsion, he contributed particularly to gravitational and inertial sensors and low-loss electronics.
Forward was born on 15 August 1932 in Geneva, New York. He obtained his BS in physics from the University of Maryland in 1954, an MS in applied physics from UCLA in 1958, and his PhD from the University of Maryland in 1965. For his thesis, he built and operated the first bar antenna for gravitational wave detection; he did this work under the direction of Joseph Weber and David Zipoy. His antenna was on display in a Smithsonian Institution museum and is now in storage there.
Beginning in 1956 and for the next 31 years, Forward worked at the Hughes Aircraft Research Laboratories in Malibu, California, rising to senior scientist on the director’s staff. In his early years at Hughes, he invented and developed gravitational radiation detectors and explored many new ideas in space applications. One such invention was the rotating cruciform gravity gradiometer mass detector, which measures Earth’s subsurface mass variations or gravitational multipole moments. In 1960, he was the first to point out that a laser interferometer gravity-wave detector could be built to be photon noise limited, and that scaling it up would make extreme events in the universe detectable.
Retirement for Forward was a simply a new category of innovation and activity. He took early retirement in 1987 and founded Forward Unlimited. The appropriately named company emphasized space propulsion methods, including using laser- and microwave-driven sails and antimatter propulsion for high velocities.
Through his concepts for matter and antimatter rockets and laser- and microwave-driven sails, he explored the only technically credible ways of sending probes to the stars; such craft can reach speeds necessary for those vast gulfs. His book Mirror Matter: Pioneering Antimatter Physics (Wiley, 1988), written with Joel Davis, presents his ideas on matter and antimatter rockets.
In 1992, Forward formed Tethers Unlimited Inc with Robert Hoyt. The company specializes in innovations for space travel using elegant mechanical methods. He retired again just before his death.
Forward’s written work consists of 157 technical publications and 71 popular science articles. His 14 book-length works include science fact and science fiction. His best known novels are Dragon’s Egg (Ballantine, 2000), which is about life on a neutron star and is still used in astrophysics courses, and Rocheworld (Baen Books, 1990), which is based on his concept for propulsion using laser-driven sails. He was among the most rigorous of the “hard” science fiction writers. His best nonfiction summary work is Indistinguishable From Magic (Baen Books, 1995), based on Arthur C. Clarke’s Third Law, “Any sufficiently advanced technology is indistinguishable from magic.”
Elegance of concept marked his many inventions; in all, Forward obtained 20 patents. Orbital tethers will be both graceful and useful. In a long series of papers, many with Hoyt, he calculated how light cables could be used to transfer energy and momentum between spacecraft; that effort opened new methods of orbit changing. Cables carrying electrical currents can raise or lower orbits by using the J × B force, available from Earth’s magnetic field. Forward believed that antimatter could provide the most fundamental method of containing energy. In the 1980s, he published 18 issues of his privately circulated journal, Mirror Matter Newsletter, to stimulate the field. He saw how magnetic traps could make antimatter useful in medicine, principally in tumor treatment.
Forward lived up to his name: His thinking was well ahead of his time, and he was known for a positive, supportive, and playful manner. We knew him primarily as a pioneer of beam-driven sails, but he had a thousand other interests. Some of his papers have amusing titles, such as “Laser Weapon Target Practice With Gee-Whiz Targets.” He fancied wearing colorful vests to go with his exciting ideas, concepts nonetheless developed with full conservative scientific rigor. Knowing of his fatal illness, he devoted his last months to writing out his newest, partially explored scientific ideas.
Of Forward’s many innovations, some were realized in his life, but most will likely emerge in 21st-century space propulsion and gravitational wave detection. Now that the first solar sails are about to be launched and plans are being made to beam microwaves at them to demonstrate photon propulsion, Forward’s ideas are starting to become real. He was fond of saying that he wrote science fiction to advance ideas that he couldn’t get into the scientific journals. He usually coupled his science-fiction writing to his science papers and thus gave concepts a wider publicity and advanced public understanding of what the consequences of these ideas could mean.
