The founder of the Tau Zero Foundation takes a look at the promise of Star Trek, and asks where we stand with regard to the many technologies depicted in the series. My own first memory of Star Trek is seeing a first year episode and realizing only a few days later that it had been one of the few times a TV science fiction show never mentioned the Earth. That was an expansive and refreshing perspective-changer from the normal fare of 1966, though back then I would never have dreamed how much traction the show would gain over time. But with the series now a cultural icon, how about Starfleet’s tech? Will any of it actually be achieved?

by Marc Millis

This week marks the 50th anniversary of Star Trek‘s debut. In just 3 seasons, the series started a cultural ripple effect that’s still going. The starship Enterprise became an icon for a better future – predicting profound technical abilities, matched with a rewardingly responsible society, and countless wonders left to explore. Many engineers and scientists trace their career inspirations to that show. The effect spread worldwide and has been described as a yearning for “a deep and eternal need for something to believe in: something vast and powerful, yet rational and contemporary. Something that makes sense.” [1]

Now, half a century later, how are we doing toward realizing the fantastic futures of Trek? Are we making progress on faster-than-light flight (FTL), control over inertial and gravitational forces, extreme energy prowess, and the societal discipline to harness that much power responsibly?

I directed NASA’s “Breakthrough Propulsion Physics” project – NASA’s first documented inquiry into the prospects of Star-Trek-like breakthroughs – controlling gravity for propulsion and achieving faster-than-light flight. That project was funded from 1995-2002, and continued unfunded through around 2008. With the help of networks beyond NASA via the Tau Zero foundation, the results of the NASA work plus many others were compiled into Frontiers of Propulsion Science, (2009). There has been some more progress from multiple places since then, but by and large that compilation is still a decent starting point into the details.

FTL

Let’s start with the most obvious and glamorous – faster than light flight. The first scientific paper about FTL wormholes appeared in 1988 [2], followed 7 years later with an extensive scholarly book on the topic [3]. Alcubierre’s “warp drive” paper appeared in 1994 [4] and a recent progress report on FTL approaches is available here [5].

In short, FTL is now a theoretical possibility, anchored in Einstein’s general relativity, even though daunting challenges remain. Instead of violating the lightspeed limit through spacetime, these theories are about manipulating spacetime itself – which is an entirely different situation. A significant next-step challenge is to find a way to create bare negative energy – and a lot of it. While negative energy can be created now (such as within Casimir cavities), the catch is that it is still contained inside of a greater amount of normal positive mass-energy. The first experimental demonstration of bare negative energy would be a pivotal moment.

A few other lessons followed: Wormholes are likely to be a more energy-efficient way of achieving FTL than warp drives. The previously touted time-travel paradoxes that seemed to prevent FTL have been found to be non-issues (You cannot use FTL flight to go back in time and kill your grandfather before your father is born). And the last lesson is that better theoretical tools are needed. Many of the FTL investigations have been limited to 1-dimensional analysis rather than full-up 3D spacetime. The theory for FTL flight is there, but still in its infancy.

For fun, I calculated how fast we would need to fly to get as much action as Captain Kirk. In their 5-year mission (of 3 seasons) they seemed to encounter a new civilization almost every episode – 79 episodes. Combining that with a provisional estimate of 1900 light-years between civilizations [6], yields a required speed of 30,000 times lightspeed. That’s about 300 million times faster than today’s spacecraft.

Recall that, on interstellar scales, lightspeed is slow. At lightspeed, our closest neighboring star, Proxima Centauri, is over 4.2 years away. Our next nearest 10 stars are within about 10 light years away. To reach Proxima Centauri within a person’s career span (say 42 years), we have to get our spacecraft up to 10% lightspeed. That’s over 1000 times faster than we’ve done before.

Transporters

To reduce production budgets, Trek included “transporters” to move people from one point to another with just a scene change – plus noises and lighting effects. The premise is that the people would be dematerialized into some sort of energy beam that could then rematerialize somewhere else. Despite the similar nomenclature with “quantum teleportation” (a real thing) Trek transporters are an entirely different animal. The closest thing in the scientific literature to creating a transporter effect is a wormhole – discussed previously.

Control over Gravitational and Inertial forces

Many of the key features of the starship Enterprise require the ability to manipulate gravitational and inertial forces. The most obvious feature is internal gravitation for its crew – which conveniently matches studio conditions. Think about it – in the middle of space, far from any gravitating body, there is no “down” to fall toward. Things just float.

The ability to induce a gravitational field inside of a spacecraft would be a huge breakthrough with all sorts of spin-offs. If we could induce a gravitational field inside the spacecraft, then why not outside as well – as a form of propulsion? This leads next to concepts like “tractor beams” and “deflectors,” to push objects out of the way of the screaming-through Enterprise. And… if you can push and pull distant objects, it’s likely that you can also sense them in a way that defies contemporary familiarity, such as identifying distant objects by their mass density (convenient for gold prospecting).

While the need for FTL is glaringly obvious, the implications of these mass-based breakthroughs are harder to grasp. Consider this analogy. Long ago, electric charges and magnets were known to exist but not understood. Things got interesting when we learned that electricity can create magnetic fields, and magnetic fields can generate electricity. Thereafter motors, generators, lighting, and… even the computer screen that you are reading this on… were invented.

Similarly, we know that gravitation and electromagnetism exist. Newton got as far as deciphering the behavior of gravity and inertia and then Einstein extended those to include electromagnetism, relativistic speeds, and intense gravitation. But we do not yet understand how that works. If we ever figure out how to use our prowess in electromagnetism to affect changes in gravitation or inertia, then all those Trek-ish visions might be realized, including zero-gravity recreational hotel rooms. The first experimental evidence of such abilities would be a turning point for humanity.

Physics in general has been seeking such knowledge and making progress since its very beginning. Over recent decades other phenomena have been discovered that challenge our existing theoretical models. There is plenty of room for new empirical discoveries and theoretical ‘ah-ha’ moments. When examined in the context of breakthrough propulsion, different lines of inquiry are added. For example, the search for “space drive” effects has revealed the importance of understanding the origins of inertial frames [7].

Extreme Energy Prowess

To achieve interstellar flight, even in the conventional sense, requires incredible amounts of energy. To bump our spacecraft speeds up to 10% lightspeed (1000 times faster than now), we need at least 1-million times more energy. While these sorts of numbers are conceivable within future decades, there are secondary issues which often get overlooked in both the fiction and even in some engineering studies. One example is how to get rid of the waste heat. When converting one form of energy to another, there are inefficiency losses. For something as small as a car engine or air-conditioner, the excess heat is easy to vent to the atmosphere. But when the energy levels get extreme and if they are used in space where it is harder to radiate that energy, then even a 1% inefficiency can lead to enormous challenges. These are not show-stoppers, but details that are a part of the big picture.

When considering the FTL theories, the required energy levels become astronomical. An old example (from Matt Visser) is that to create a 1-meter diameter wormhole, one would need to get as much rest-mass-energy as the whole planet Jupiter, convert it in the form of bare negative energy, and then make it small enough to create that 1-meter opening. Subsequent analyses have brought those estimates much lower, but we are still talking mind-boggling feats of energy prowess. Any new theory or experiment that shows how to warp spacetime with achievable energies would be a pivotal development.

A significant secondary issue is how to use that energy safely. The energy levels of interstellar flight are so great that, if misused, could wipe out all life on Earth. This leads to another key feature of the Star Trek visions – a mature society that wields its power responsibly.

Societal Maturity

Although Star Trek was thought-provoking from the technological point of view, it was also very comforting from a sociological point of view. The crew of the Enterprise behaved in an honorable and respectful manner to each other and to other cultures, despite differences in background, race, sex, or character. They did not abuse their power. Even though they worked toward common goals, each individual had their special niche. Several episodes featured the crew of the Enterprise coming to the rescue of some civilization that gone astray because of their lack of sensible treatment toward each other. Most often those wayward societies would learn their Trek lesson and turn the corner to a better life. If only it were that easy to get people to override their errant beliefs with facts, wisdom, and a good role model.

Of all the challenges, this one is probably the most difficult and the most needed. The survival of humanity. depends on it. To safely wield our growing powers, our society will have to mature to where we work for the common good rather than against each other. A glimmer of hope is that we have refrained from unleashing a nuclear holocaust for over a half century, despite precarious international bickering from time to time. I’ve also read articles that, proportionally, we are killing each other less. Compared to human history, however, a half-century is a tiny moment. As the decades tick by and our energy prowess grows, will all of us wield our powers responsibly? Will we learn to live in a manner where our disagreements do not become life-threatening?

The difficulty of creating these societal improvements is that the tools we have are the same thing that we are trying to fix. To make society healthier, we need a healthy society. When we are part of the problem that we are trying to solve, there is a limit to our perspectives. It’s a bit like asking a vacuum cleaner to suck itself up.

One way to step back and see ourselves more impartially is to contemplate far future societies in the form of “world ships.” Imagine a colony of 50,000 people constrained in a finite ship headed across space for centuries. In addition to sustaining physical life support, their society will have to sustain a peaceful and meaningful culture. Such challenges are explored in the disciplines of Astrosociology and Space Anthropology. Perhaps as more rigorous data about human behavior accumulates, along with methods for complex data analysis, we will eventually figure out how to design a society that accommodates the full realities of human behavior in a manner where individuals can live meaningful lives within a lasting peaceful culture.

Closing Thought – Reflections on Proxima b

It’s been said that having a moon so close to Earth helped create the space program. The science fiction for that step began with Jules Verne in 1865, followed by the mathematical foundations from Konstantin Tsiolkovsky in 1903, and culminating in the Apollo moon landing in 1969. Roughly a half century from fiction to science, and another half century from science into substance.

Now we have an potentially habitable planet as close as it could possibly be. Our nearest neighboring star, Proxima Centauri, has a planet a little bit bigger than Earth which might have liquid water. It’s 4.2 light years away, has a mass 30% more than Earth, and is in the habitable zone of its red dwarf star. Its star is dimmer, cooler, and tiny compared to our Sun (14% the size, 12% the mass), which means that its habitable zone is only 5% the distance between our Sun and Earth. Accordingly, a year on the new-found planet is only 12 Earth days. The science is here.

For those of us who have been contemplating interstellar flight longer than we’ve known better (Tau Zero is a decade old this year), it couldn’t get any better than this – unless we later learn that the planet does indeed have an atmosphere, proof of liquid water, and the right spectral clues for life. This distance makes it within reach of conceivable probes. Just earlier this year, billionaire Yuri Milner committed $100 million for research into one approach to interstellar flight, laser pushed light sails, dubbed Breakthrough Starshot. That particular idea is decades old, with the first detailed analysis done by Robert Forward in the 1980’s. Starshot hopes to nudge the idea from concept to technological proofs of concept.

Centauri b beckons. Will this be the catalyst to nudge interstellar flight toward reality? Consider that the notion of space sails dates back to at least 1929 (and can actually be traced in some form all the way back to the works of Kepler). Those foundations were converted into science by the late 1980’s, and Starshot is trying to mature the science into technology now. If the pattern of the Moon shot repeats, we’ll have probes on their way to Proxima by the 2040s. And consider this. The science fiction for faster than light flight dates back to John W. Campbell in 1931, and the first science articles were in 1988 and 1994. If the pattern repeats there too, we might have warp drives reaching the planet “Proxima b” before Starshot even gets there.

Ad astra incrementis

References

[1] Greenwald, J. (1988). Future Perfect: How Star Trek Conquered Planet Earth. (Viking).

[2] Morris, M. S., & Thorne, K. S. (1988). “Wormholes in spacetime and their use for interstellar travel: A tool for teaching general relativity.” Am. J. Phys, 56(5), 395-412.

[3] Visser, M. (1996). Lorentzian wormholes. From Einstein to Hawking. (AIP Press), 1.

[4] Alcubierre, M. (1994). “The warp drive: hyper-fast travel within general relativity.” Classical and Quantum Gravity, 11(5), L73.

[5] Davis, E. W. (2013). Faster-Than-Light Space Warps, Status and Next Steps. In 48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit (p. 3860).

[6] Maccone, C. (2011). “SETI and SEH (statistical equation for habitables),” Acta Astronautica, 68(1), 63-75.

[7] Millis, M. G. (2012). “Space Drive Physics: Introduction and Next Steps.” Journal of the British Interplanetary Society, 65, 264-277.