Normally this newsletter about the long-term future is all-digital — it’s in the name. But sometimes the “future” depends on some very physical questions that also deserve attention. One of these is how we’ll someday get around in space. We aren’t the only tech people fascinated by this question; when moguls like Jeff Bezos and Elon Musk make money on digital tech, they pour it enthusiastically into space projects. Their main products right now are rockets to get off the Earth’s surface, but the real long game — the kind of thing that preoccupies tech billionaires and NASA planners — is what happens next. Musk wants humanity to think about its potential future as “a multiplanet species & true spacefaring civilization,” NASA’s long-term human space travel plans now live firmly in the “research” zone, but its ideas for propelling craft deeper into space aren’t just experiments anymore. One idea with momentum is electric propulsion, the idea that a spacecraft can be powered by small amounts of thrust for long periods of time — key for missions potentially lasting years, not just days or weeks. “Instead of expelling large amounts of mass that you light on the fire using a traditional chemical combustion — the kind of rocket engines you see launching off of Cape Canaveral, huge plumes of red flame and tons of smoke — you are exciting tiny particles using electricity and and shooting them out the back end of a rocket,” said Thomas Roberts, a graduate research fellow at the MIT Astrodynamics, Space Robotics and Controls Laboratory. He was describing ion propulsion, a popular subset of electric propulsion that researchers have had their eye on. The idea has been around for over a century, and is now in use both by NASA and some commercial projects. SpaceX’s smaller satellites already use electric thrusters to maneuver, with the company’s Starlink constellation being the most popular case. A few years ago, NASA tested an ion engine that could theoretically be deployed to ward off an apocalyptic asteroid. Experiments in newer or more ambitious forms, the kind you might power human flight with, are proliferating, along with some homebrew projects. Roberts acknowledged that ion propulsion may be having a moment, though, he cautions, “‘moments’ when it comes to space missions are a bit slow-paced — things that make it to space today were conceived many years ago, especially when they're run by a government agency.” Former NASA Administrator Sean O’Keefe has been a long-time proponent of the technology, and believes we could see it used for human space travel soon: “I think a decade is a reasonable proposition to actually go through a development phase,” he told Digital Future Daily. “We’re within striking distance of that capability.” But, as with everything, politics eventually enters the equation. Many of these ion-thruster models are nuclear-powered, using small reactors to generate electricity that positively charge gasses like xenon or krypton. Because of Americans’ mixed feelings about nuclear power, “I do not see the U.S. using nuclear-powered electric propulsion for human spaceflight without a serious cultural change,” Roberts said.
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