Time and again we hear that we are behind the aerospace curve; that we should be farming peanuts on Mars by now; mining Helium-3 in some far-flung lunar lava tube, or living the dream in a space condo parked in low-Earth orbit. But nearing the 50th anniversary of humankind’s first steps on the Moon, we appear to have wavered in our commitment to crewed exploration.
Even so, within the last century and a quarter we have gone from the Wright Brothers at Kitty Hawk to skirting the outer reaches of our solar system; from a quaint Boeing tri-motor passenger biplane to airliners that continually shrink the globe.
After a recent visit to Seattle’s Museum of Flight, it was hard not to be startled by the juxtaposition of a Lockheed Electra 10-E, not unlike that flown by Amelia Earhart, with the world’s fastest piloted aircraft, the Lockheed SR-71 Blackbird. And literally across the road, it’s possible to walk through the aisle of the Boeing 707 that once ferried President John F. Kennedy, the only president that seemed to be truly serious about human spaceflight.
Back during the heady days of Apollo, the Moon and stars seemed ours for the taking. But in this current age of uncertainty, it’s easy to wonder if we will ever travel to Alpha Centauri?
Most likely. But there’s a mismatch between quick definitive answers that sound exciting, and getting the real work done which is slow, uncertain, and painstaking, Marc Millis, the former head of NASA’s Breakthrough Propulsion Physics (BPP) initiative at Glenn Research Center in Cleveland, told me. He says that it is too easy for under-qualified propulsion “researchers” to self-promote; adding to the pool of unproductive distractions.
Even so, theoretically, in terms of making interstellar propulsion a reality, we may be further along than most people realize.
In a 2018 breakthrough propulsion study, based on work done with the Colorado-based Tau Zero Foundation and in part with a grant from NASA, lead author Millis notes that theories for faster-than-light (FTL) flight are now part of the scientific literature.
Millis and colleagues note that the first traversable wormhole article was published in 1988. The first warp drive paper in 1994. And the first scholarly book compiling these challenges along with other breakthrough propulsion pursuits was published in 2009.
But it’s also true that at its present rate of propulsion, NASA’s Voyager 1 spacecraft, launched more than 40 years ago would still take another 80,000 years to reach the Alpha Centauri star system, only four light years distant.
And in between these vast distances, as Millis and colleagues note in their study, points of real interest are few and far between and at thousands of Earth-Sun distances (or astronomical units (AU).
“There exist only sparse densities of comets and asteroids; the Hills Cloud (2,000 AU), Oort Cloud (10,000 AU), and the G-Cloud (41,000 AU),” the study notes. Beyond the Centauri system, Millis and colleagues write that there are already eight known potentially habitable planets detected within 41 light years of Earth.
The authors estimate that distances to the closest truly Earth-like planets might range between 50 to 100 light years. This means that even if Earth-based rocket engineers can fabricate space probes that could reach speeds approaching that of light, the probes themselves have a limited lifespan. They estimate in their study that the longest possible operating duration for a space probe may be no more than 200 years. If so, they note that even a probe traveling at lightspeed could only travel 200 light years into the galaxy before its hardware would fail completely.
But we are only now looking into interstellar probe designs that could last indefinitely, or at least for centuries. It’s all a part of both theoretical and practical engineering design work that would be needed if humanity is ever going to get serious about becoming an interstellar species.
Millis argues that such work requires what he terms “dispassionate rigor to investigate the pertinent loose ends in physics.” How the work is done is what dictates progress, he says .
“The Wright Brothers did not succeed because they had the right device,” said Millis.
“They created the right device because of how they did their work; systematic investigation on more than one method, open to learning by trial and error.”
Millis says that the ideal U.S. federal agencies to fund such a breakthrough propulsion interstellar project include NASA and the National Science Foundation (NSF). The wrong agencies to fund this include the Dept. of Defense (DOD) and DARPA (Defense Advanced Research Projects Agency), he says.
“Their pitfalls include limited public disclosure, a selection process that favors jumping to conclusions, and a focus on the final product before understanding the operating principles that could lead to a final product,” said Millis.
Meanwhile, this Spring, Millis plans to collaborate with a team at Germany’s Dresden University of Technology that is experimentally testing a few claimed breakthrough propulsion devices. The first results of these tests are expected by the end of this coming Summer.
Although Millis still seems passionate about progress on breakthrough propulsion, he’s not one to suffer fools. And he’s also realistic when it comes to thinking about how to fund such efforts.
Millis says it would cost $2 million per year just to resume progress of NASA’s Breakthrough Propulsion Physics program, which ended in 2002. But to make real progress, through tireless, dispassionate trial and error both at the theoretical level and in the lab will require a global public-private and non-profit effort for decades to come.
Thus, Millis poses the following very valid questions: How much would a warp drive be worth to you? And within your lifetime, how much would you be willing to pay for round trip access to another earth-like planet?