The Space Reviewin association with SpaceNews

Illustration of SpaceCub, a proposed homebuilt suborbital spacecraft. (credit: D. Burkhead)

The promise of amateur suborbital spaceflight

<< page 1: the technical challenges

Dealing with risk and regulation

One of the major obstacles to starting a large project such as building a high-performance vehicle (regardless of whether it is a rocket, an airplane or a blue water cruiser) is the issue of risk. The risk of accidentally harming oneself is not the problem—it’s the risk of investing huge amounts of time and energy in a project, only to have it fail partway through, or to find that it is costlier and more time consuming than anticipated. The only way to mitigate this risk is for a few trailblazers to actually build spacecraft, developing ways of dealing with the obstacles they encounter along the way. Among the obstacles that will need to be dealt with are the difficulties of supersonic flight (there has not yet been a supersonic homebuilt aircraft), and the thermal problems associated with reentry. Once a few people have shown it can be done, others will feel more confident that their efforts will not be in vain, and will start building vehicles of their own.

Once there is a modest number of people building vehicles, companies will start taking the spacecraft homebuilder market seriously, and we will see products targeted at this market, driving the cost (and hence risk) down still further. When companies are offering products specifically aimed at spacecraft homebuilders the community will have reached the tipping point at which it becomes a viable self-sustaining community. By analogy with the aircraft and yacht homebuilder community, the amount of money people are willing to spend should be about $150,000, with a build time of roughly 2000 hours spread out over five years. This is typical of the amount of time and money ambitious aircraft and yacht homebuilders expend on their projects. Interestingly enough, for the more ambitious of the submarine homebuilders the amount of time spent is about the same, but the amount of money invested is considerably less—about $20,000 is typical. This probably reflects the fact that the homebuilt submarine community is still developing: there are very few sets of plans available, and only a small community to support the homebuilder. Both of these factors increase the risk of the project fizzling out or failing due to unanticipated technical problems, reducing the amount of money people are willing to invest in the venture. This is beginning to change, thanks in part to the Internet bringing together enthusiasts from around the world.

By analogy with the aircraft and yacht homebuilder community, the amount of money people are willing to spend should be about $150,000, with a build time of roughly 2000 hours spread out over five years.

One major uncertainty is the regulatory environment that homebuilt spacecraft would face. Since it is not in commercial service the requirements are likely to be somewhat easier to meet than those faced by the suborbital startups. On the other hand, there are still many regulatory requirements that must be met, from FAA waivers to environmental considerations. Until somebody actually flies it we can’t be sure how the FAA and other interested agencies will view homebuilt spacecraft. Preliminary indications from the office of the FAA Associate Administrator for Commercial Space Transportation (AST) are that they are favorably disposed towards suborbital spaceflight, though whether this extends to homebuilt vehicles remains to be seen. Once again, only after a few people have flown will we know how much of an obstacle regulation represents.

It is clear that a vehicle capable of achieving X Prize class performance can be built by private individuals. The necessary construction techniques have all been demonstrated on other types of vehicles built by amateurs. Overall design of a suborbital vehicle is a harder problem, but by all indications it is well within reach for a group of intelligent and disciplined individuals. Once a few groups have succeeded, and there is a set of proven designs available, it seems reasonable to believe that a homebuilt suborbital spacecraft will end up being within reach for a dedicated and persistent group of private citizens.