I'm starting a new series of posts here, in which I interview people whom I consider to be at the leading edge of space entrepreneurial activity.

My first victim is Jeff Greason, a founder and head of XCOR Aerospace.

Jeff is a Caltech grad, and a former project manager at Intel. After several years of doing damned good amateur work on rocket engine analysis and design, he left Intel to work for Rotary Rocket, as head of their engine design group.

Once he'd seriously gotten the space bug, and Rotary folded, he took some of the members of the team (Dan DeLong, Aleta Jackson, and Doug Jones) and they jointly founded XCOR. Recently, the company acquired some of Rotary's assets.

XCOR made the news in the past year by flying a rocketplane, as a means of proving out the concept of making such vehicles operable and reliable, which is a key step in getting affordable space transportation.

Transterrestrial: Thank you for consenting to this grilling on a non-dead-tree publication, Jeff.

I'm curious about the potential effects on the evolving regulation of space transports of any upcoming X-Prize attempts. Now that the prize seems to be fully funded, with a two-year clock ticking until the money turns into a pumpkin, it seems to me that the pressure to launch things fairly soon is going to grow.

While you aren't listed as a potential contestant, I'm aware that you have plans to build suborbital vehicles in this class, and have been working closely with the FAA to define the rules of the road, so to speak. When it comes to suborbital vehicles, the Commercial Space Transportation Act is less than clear as to just what that term means.

I've not seen anything to indicate that the FAA has really gotten its act together on what constitutes a launch system for those purposes, or which specific branches of that agency will regulate it, and how. In light of that, X-Prize contestants (at least the American ones) would seem to run the risk flying into a regulatory vacuum, or chaos. Can you shed any light on that situation that could be published on my weblog?

Greason: That's a very timely question. XCOR has been working with the FAA to clarify what regulations will apply to suborbital vehicles. This kind of vehicle really wasn't envisioned when aircraft regulations were created, nor was it envisioned when Congress created commercial space regulation. There are different regulations, laws, and treaties that apply to airplanes and launch vehicles, and so it really does matter which category suborbital vehicles fall into.

The FAA is well aware of the issue and they have been working on it for many months now. It takes time, because all of the different parts of the FAA have to agree on just where to draw the line between aircraft and launch vehicles.

I think it is clear that suborbital vehicles are launch vehicles, or "suborbital rockets" as Congress referred to them in the law. The question then is just what is suborbital. Is it an altitude, and if so, what altitude? Is it a velocity? A trajectory?

My own opinion is that the essential feature is getting out of the atmosphere. In some sense, if you're flying high enough that you need attitude control rockets to steer, I think you're clearly above the air, as far as your vehicle is concerned. I think that's the right approach because airplanes, by definition, are vehicles supported by lift; and if you're operating at altitudes where lift is not an option, you're not an airplane.

Transterrestrial: Before you answered that in the way you did, I might have postulated some kind of energy criterion--in other words, kinetic energy (vehicle speed) plus potential energy (altitude). Now that you've put forth the idea, it seems to me that any vehicle that requires an attitude control system (ACS) employing rockets (i.e., you're out of the sensible atmosphere), is a much cleaner line. Is that one of the things that you have in mind?

Greason: Yes, that's one of the possibilities, although just how you define "high enough to need an ACS" is more complicated than it may seem at first glance.

Transterrestrial: Well, my thought was that if the vehicle had an ACS, it would presumably need it, otherwise it would be dead weight. So vehicles that have ACS could sensibly be vehicles that were intended to fly that high, and should be categorized as space vehicles.

Greason: Well, that would be one possibility acceptable to XCOR.

Transterrestrial: And since that's a simple yes/no question, let me follow up. Who regulates test flights of a vehicle, that requires an ACS, but doesn't go out of the atmosphere on a particular test flight, and under what rules?

Greason: I've asked the FAA that question but I don't yet have an answer.

Transterrestrial: Perhaps I misstated the question. I was looking for your opinion as to "ought," rather than "is." Do you have a particular desired outcome in mind?

Greason: A suborbital vehicle is either going to be a launch vehicle or an experimental aircraft during test flights. Either would be acceptable to us as long as the means of transitioning to operational revenue flights is clear. However, since we can't carry cargo or passengers for hire in an experimental aircraft, the criteria for moving to launch vehicle operation has to be both unambiguous and reasonable.

If test flights are done as an experimental aircraft, that makes test flights easier but it delays getting experience operating under launch vehicle regulations. Those advantages and drawbacks are roughly balanced in our view.

If the line between aircraft and vehicles depends on "what they do," rather than "what they are," we would logically do test flights as an experimental aircraft, until they are doing something above the line. So if the line turns out to be an altitude, for example, we'll have early test flights under a different regulation than operation. If the line is an attribute, such as high impulse capability or having an ACS, we'll probably do all the flights as a launch vehicle.

Transterrestrial: So, bearing in mind that the X-Prize clock is ticking, do you see any danger ahead if someone attempts a flight prior to resolution of this issue?

Greason: Right now, I think what the industry needs from the FAA is regulations which are both reasonable and clear. When there is too much room for judgement calls, it makes the regulations uncertain, and that uncertainty inhibits investment.

I am hopeful that the FAA will resolve these questions before an X-prize flight. If that didn't happen, it would certainly tend to confuse things further. That might delay establishing definitions for launch vehicle operation--and we have to have that before we can start revenue-generating flights.

Transterrestrial: Is there some reason why the general public, or anyone in Washington, should be concerned about any delay in resolving the regulatory uncertainty? Is it really a problem, and if so, what dire events might result from the uncertainty extending for the next couple of years?

Greason: Well, if the uncertainty goes on for a few years, how do we know what to build, or how to license it, or how to insure it?

Experimental airplanes are fine for test flights but if you want to make money and fly as a launch vehicle, you have to get a launch license. Right now, if you submit a license application, the clock doesn't even start ticking for giving you your license until the FAA figures out whether it's a launch vehicle or not.

Transterrestrial: What can you tell us about XCOR plans for revenue-generating flights? Is building Xerus still the baseline plan, and do you have a firm schedule for it? I notice that Popular Science has it listed as a candidate for the "Best of What's New" for aviation and space, and they'll be announcing the winner on Friday.

[Note: since the interview, the Eclipse 500 corporate jet was selected as the winner. I suspect that if XCOR actually flies Xerus, though, it'll stand a pretty good chance of winning in whatever year that occurs.--ed]

Greason: We try to minimize discussion of our future plans, but the Xerus is still our plan for substantial revenue, and the schedule will not firm up until we finish raising the necessary capital. Three years after we get the money in the bank we should reach revenue flights.

Transterrestrial: What do you see as the path for low-cost access to orbit from here?

Greason: The Xerus carries an expendable upper stage which puts very small payloads (10kg) into LEO. Once we have proven all that, we can do a larger, but generally similar, suborbital vehicle and upper stage for larger payloads. Then we can develop a reusable upper stage to replace the expendable upper stage--and by that point the price should be low enough for orbital passenger flights.

Transterrestrial: Cool.

Good luck, and let's hope you're right.