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Interstellar Flight: A Progress Report

When it comes to star travel, some people won’t take no for an answer

Those pursuing the idea of interstellar flight remain undaunted. “We have to keep pushing,” says Richard Obousy, an organizer of the Starship Congress and a director of Icarus Interstellar, the conference’s host organization. “It’s a long, hard road, but what humanity is capable of on long time scales is tremendous.”

The long-road, long-time-scale theme is a common one. It’s reflected in the title of the group that won this field’s equivalent of the lottery: a half-million-dollar grant from DARPA. The 100 Year Starship (100YSS) organization, which was created after a 2011 agency-sponsored conference, is charged with developing the infrastructure needed to make it possible to launch a crew-carrying starship within the next century.

“Our task is to push radical leaps in technology design,” says 100YSS director Mae Jemison, a physician and former space shuttle astronaut who once guest-starred on “Star Trek: The Next Generation.” “I’m sure that we can create the capabilities. That’s a rather radical and bold thing to say. But I always think about putting a human on the moon.... When President Kennedy proposed landing a person on the moon in 1961, we had barely gotten someone off on a suborbital flight.”

The group’s early focus has been less about leaps in technology than about the mundane tasks of running an organization: raising money, arranging conferences, setting up a research institute. Much of the emphasis so far has been on education, public outreach, and linking starship research to problems on Earth. That has led to some of the more technology-oriented folks in the interstellar community feeling mildly resentful. Icarus, an original partner in the DARPA grant, dropped out “to pursue our own way,” Obousy says.

Yet Jemison, who operates 100YSS from a small suite of offices in Houston’s eclectic Montrose neighborhood, says the challenges of building a starship go far beyond just designing the hardware. “Everything that we need to know to have a successful human trip beyond our solar system are the very same things that we need to know to survive as a species on this planet,” she says. “If we look around us, we’re already on a starship.”


If our goal is to escape this particular starship and head for a similar one orbiting another star, we’ll need some kind of advanced propulsion. The topic brings out, depending on your perspective, radical dreamers—or just radicals. Starship Congress offered ideas for fission-fragment rockets, inertial containment fusion power, magnetic sails, and FTL (faster-than-light) warp drives, among others. Some concepts, like gigantic solar sails, are allowed by the laws of physics, but require engineering well beyond today’s capabilities. Others, like matter-antimatter engines and warp bubbles, draw oohs from the faithful but mild snickers from the more skeptical, who say the plans require too many leaps of faith.

“If you really want to get something done, science fiction won’t get it built,” says attendee Philip Lubin, a professor of physics at the University of California at Santa Barbara. “In some of the presentations, it was ‘A miracle is required here, a miracle is required here, a miracle is required here.’ But there was no acknowledgment of that.” Lubin acted as conference contrarian, frequently asking presenters pointed questions about their proposed technologies. But he also offered up his own sci-fi-sounding project: a planetary defense system that could double as a solar sail’s power source, using beamed energy to propel an unmanned probe to the stars.

The system would collect sunlight with miles-wide solar arrays in Earth orbit and convert it to a beam of energy, similar to a giant laser. Lubin says that over a year, such a beam could completely vaporize a threatening asteroid a third of a mile (1,760 feet) wide at a range of one astronomical unit—the distance from Earth to the sun (93 million miles)—and deflect much larger ones. “It wouldn’t require any miracles, just a lot of hard work,” he says. Such a system could start on a much smaller scale—big enough to zap space debris, perhaps—then be expanded as engineering and funding allow.

If used to propel starships, the energy beam could boost probes to substantial speeds, Lubin says. A 100-kilogram (220-pound) probe with a 100-foot reflector to catch the beam could reach Mars in three days; with a much larger reflector, such a probe could hit three percent of lightspeed—up to 20 million mph—by the time it reached the edge of the solar system in less than a month.

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