tau zero tries to read kardashev’s tea leaves

According to a study by the founder of the Tau Zero Foundation, a collective of space enthusiasts focused on the potential for interstellar travel, which last year published a paper on what it might take to reach a nearby star, we won’t be ready to launch anything outside the solar system by 2196 or so. You see, if we use typical projections of energy use across the globe and then factor in roughly how much of it is used for a number of space-related pursuits like shuttle launches, we can create an equation which tells us in how many years we can expect to see spacecraft capable of generating the required energy to travel to Alpha Centauri. Wait, what in the name of all things Newtonian is Marc Millis doing? Is he seriously including the thrust of the shuttle into the facts and figures for global energy usage across the world as if the two were somehow related? This isn’t even mathematical abuse, it’s abstract algebraic numerology based on extremely poorly thought out notions and basic, straight-line projections which fail to take modern and future real world issues into account.

As in many flawed papers on arXiv, the problem here isn’t necessarily the math itself or the equations used to derive the conclusions, but the basic concept behind the entire study. In this case, we have an author trying to estimate when enough energy for a one-way interstellar flight will be available based on the ratio of the kinetic energy of the shuttle during takeoff to the nation’s energy consumption. Now, we can ask where all the military and scientific satellite launches figure in all this and why they’re not being included, but the mistake here is a lot more profound than that. The only relationship between a nation’s annual energy usage and rocket launch capacity is the amount of fuel it has available to fill up those rockets. How many rockets it launches and where is up to that nation’s space program and its priority list. Overall we could groan a little and see how much fuel is being used on average for an annual volley of launches, then compare it to energy reserves and proceed to straight-line estimates about future launches, but all that would be totally irrelevant when we’re talking about a potential interstellar mission. Fill a massive generation ship or a probe with enough fuel to get to another star even a little faster than the eons it would take with current propulsion methods and the craft would be way too heavy to launch itself anywhere at all. We’d need brand new propulsion technology for craft like these.

And what about the development of this brand new technology? Millis makes an energy budget for it, implying that once humans are devoting the equivalent of the energy the craft would have to expend to make a trip to an undetermined place near Alpha Centauri, we could have a shot at interstellar travel. In reality, we might never develop the kind of fusion reactors we’d need for a starship, or have them in the next decade depending on a wide variety of factors, including the money and effort we devote to it, how fast scientists work on it, the laws of physics and what they’ll permit us to do, and of course, the occasional role of serendipity. Projecting how fast or how slow technology will develop is generally a fool’s errand unless we’re talking about something already on the horizon. And no, the specific impulse of the planned spacecraft will have nothing to do with whether we would have the capability to fly to the stars. It’s just an engineering requirement for a specific piece of space- faring machinery, not an energy budget to be used for interstellar travel when we reach it. We don’t even have to generate it, that’s the spacecraft’s job. All we need to do is supply the appropriate technology, crew, and the political willpower to commit to what would no doubt be a very expensive and long mission. It’s our drive to go to the stars and our commitment to making something like that possible that we need to harness, not several abstract ratios derived from flawed reasoning and forged into irrelevant equations.

See: Millis, M. (2010). Energy, incessant obsolescence, and the first interstellar missions, arXiv:1101.1066v1