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NSRC 2020

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Review: Microlaunchers

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Microlaunchers: Technology for a New Space Age
by Charles Pooley and Ed LeBouthillier
CreateSpace, 2013
softcover, 200 pp., illus.
ISBN 978-1-4912-8111-6

Rocket development today is going in two, seemingly divergent directions. One direction is towards bigger rockets, like SpaceX’s Falcon Heavy, designed to carry more than 50 tons into low Earth orbit (LEO), and NASA’s Space Launch System, which will initially carry 70 tons into LEO with an ultimate capacity of 130 tons. On the other hand, there’s growing interest from government agencies and startup companies alike in very small vehicles for dedicated launches of smallsats, vehicles that can place just a few hundred, or even a few dozen, kilograms into LEO.

“Everything else will follow when launch technology is available to a much wider population,” the authors argue.

Even those “small” vehicles, though, would likely be too large for Charles Pooley. For years, he has advocated the development of so-called “microlaunchers” that could carry very small payloads—on the order of a kilogram or even less—into space. In the past, such tiny payloads could be dismissed as being effectively useless, but that argument isn’t as strong today given the rise of CubeSats and other nanosatellites that are increasingly capable despite their small sizes. In the new book Microlaunchers: Technology for a New Space Age (which, the cover states, is the first book in the “Microlaunchers Series”), Pooley and Ed LeBouthillier try to make a very technical case for these small rockets.

Part of their argument is based on historical analogies. Just as the mainframe computing industry was disrupted forty years ago by the microcomputer revolution, so too, they argue, that the current “Mainframe Era” paradigm of space exploration can be disrupted by small launch vehicles: “Everything else will follow when launch technology is available to a much wider population.” That launch technology, they argue, is in the form of microlaunchers that are accessible even to hobbyists, building up a community of interest that stimulates demand.

Pooley and LeBouthillier dive deep into the technical details about how to build microlaunchers. Much of the book is, in many respects, an introductory treatise in launch vehicle design, with chapters on the rocket equation, engine development, and designing stages. These chapters include plenty of equations and tables, and are not for the technically faint of heart. They are, though, useful discussions of rocket engineering concepts that go beyond microlaunchers themselves.

However, Microlaunchers doesn’t convincingly make the case for such small launch vehicles. One problem is that it’s unclear what such vehicles would be used for. While there’s growing interest in CubeSats in low Earth orbit, Pooley and LeBouthillier eschew the use of microlaunchers for missions to LEO, in part because such orbits are “increasingly regulated,” but also because such spacecraft have “been done hundreds of times and it’s hardly exploration any more.” Instead, they argue for something far more technically ambitious: missions beyond Earth orbit, including asteroid flybys and space science missions. Those spacecraft are far more challenging to build, particularly when it comes to communications (they outline a technique to use laser communications to overcome this), multiplying the challenges for microlauncher developers. And, while LEO may be “hardly exploration any more,” it’s still potentially a lucrative market for startup ventures that could make use of CubeSat-class spacecraft launched by such vehicles.

What Microlaunchers does demonstrate that it’s technically feasible to build very small launch vehicles, and that such vehicles might—might—be in the grasp of hobbyists.

There’s also the question of whether there is a large hobbyist community with the interest and ability to develop microlaunchers, as the authors foresee in analogy to the computer hobbyists of the 1970s. There is an active amateur rocketry community, but that has not translated, after many years, into vehicles capable of placing even tiny payloads into orbit or on escape velocities. It’s as if the Homebrew Computer Club spent the last four decades refining calculator designs instead of creating personal computers. There may be many reasons for this, including technology, cost, regulations, and even personal interest, but the authors don’t examine why their microlauncher revolution hasn’t happened yet, or if there is a technological breakthough akin to the development of the microprocessor needed for microlaunchers to thrive.

What Microlaunchers does demonstrate that it’s technically feasible to build very small launch vehicles, and that such vehicles might—might—be in the grasp of hobbyists. However, they rely far too much on a historical analogy with the development of personal computers that is imperfect, at best: launch vehicles face challenges, from licensing and other regulations to access to launch sites, that didn’t exist in the early days of computing. Microcomputers went from hobbyists’ curiosities to ubiquity in less than forty years; unfortunately, based on the case made in this book, it’s hard to see microlaunchers doing the same.