Today, the United States is in the process of a renaissance of interstellar thought and ambition. In the popular culture, with the discovery nearly every day of potentially Earth-like exoplanets, and popular movies like Interstellar, we are seeing an increasing public interest. And in the technical community, there is new leadership when it comes to actually designing interstellar capable spacecraft, such as DARPA’s 100 Year Starship project, Icarus Interstellar, and the Tennessee Valley Interstellar Workshop.
But we could have been so much farther along. After the publication of George Dyson’s book Project Orion, and a few specials, a lot of people know that in the early 1960s DARPA investigated the possibility of a nuclear-pulse-detonation (that is, powered by the explosion of nuclear bombs) spacecraft.
Preceding but also concurrently developed with Apollo, this extremely ambitious project had unbelievable payload capability. Where Apollo at 3,500 tons could only put two tons on the Moon, the smaller Orion (about the same total mass, 4,000 tons) could soft-land 1,200 tons (600 times as much) on the Moon, and the larger (only three times as heavy as Apollo, or 10,000 tons) could soft-land 5,700 tons (nearly 3,000 times as much) on the Moon, or take 1,300 tons of astronauts and consumables on a three-year round-trip to Saturn and back!1 The fission powered Orion could even achieve three to five percent the speed of light, though a more advanced design using fusion might achieve eight to ten percent the speed of light.
http://interstellar-news.blogspot.com/2015/03/starfleet-was-closer-than-you-think.html
