The X-15 was designed for two missions: investigate hypersonic (Mach 5+) speeds and to fly to high altitudes. The X-15 eventually flew well over Mach 6 and exceeded 50 miles altitude, earning a few pilots astronaut wings.

SpaceShipOne is designed to fly higher than the X-15 but not nearly as fast (somewhere around Mach 3.2). However, it's also a multiseater! It was built for a fraction of the cost of the X-15 by a team who thinks so far outside the box that they aren't even in the same country. Their White Knight mothership alone is one of the wildest designs I've ever seen, and I've been following Rutan's career since he came out with the VariViggen in the early 1970s. I keep asking how he's going to top his latest creation, only to see him do so in spectacular fashion.

Here's an interesting interview with Burt from Air & Space magazine, possibly from a few years ago. Here's one reason for his success, IMO, with emphasis added.


Q: I would imagine it's a lot of solitary hours spent designing a plane, and yet are you also--do you have to mentor or manage aeronautical designers in the company? Do you spend much of your time doing that?

A: The solitary hours designing is what I enjoy a lot. It's not the only thing I enjoy doing, but I certainly do enjoy it. That's almost solely done on evenings and weekends--off normal business hours. Occasionally, I'll find myself locking the door and doing some of that during the week, but rarely. What people normally think of a 40-hour [work week] here is [7 a.m. to 4 p.m.] Monday through Friday. Most of that time is divided into things: I do marketing. I do proposals. I host prospective customers, work with them on their needs, show them what we've done in the past, and see if we can structure a program around them. Doug Shane at my shop here is responsible for that work, as well as for new contracts. But I do a lot of that work personally with him. I also review what other people do and just kind of look over their shoulder, see what they're doing and making suggestions.

I also get in and work on building airplanes. I get my hands dirty, still. And I insist that all of our engineers do that. The general rule here is that you don't get the privilege of designing something unless you have the capability of building it with your own hands. And that's a rule that I think is extremely important. One that's not even legal at Lockheed, Boeing, because of unions. We think it's extremely important--critical and mandatory.