Why We Miss the X-15
Not only was it the fastest. It may have been the best flight research program ever.
- By Linda Shiner
- AirSpaceMag.com, November 01, 2007
(Page 2 of 5)
But back to the original question, I think where we got off track in aeronautics was the cancellation in 1963 of the Manned Orbiting Laboratory program, we began a pattern of fits and starts that has continued to the present day. We replaced DynaSoar with Manned Orbiting Laboratory, then we didn’t build the Manned Orbiting Laboratory. Had we fulfilled Manned Orbiting Laboratory, several things would have happened. First of all, we would have achieved a space station at a much earlier date, much like the way the Soviet Union achieved a space station. The second thing is you would have had to have had a launch vehicle to get a team of astronauts up to that space station, and we actually had that system: It was called Gemini.
Beyond Gemini and the Titan launch vehicle, there were plans to take a lifting-body shape, the so-called SV-5 shape, which was an Air Force-Martin program. Then NASA came on board as well, and NASA had plans themselves to look at a lifting-body shape that they called the M-2. Northrop was willing for a price of $200 million to build a piloted, demonstration orbiting vehicle. This would have led to a routinely operating hypersonic reentry vehicle that we could have used to support operations of the Manned Orbiting Laboratory.
We turned our back on that as well. When you had then the fulfillment of Apollo in 1969 coming after the shut down of the X-15 program [which ended in 1968], and you had the cancellation of any plans to extend the X-15 program to use a delta-wing configuration and to make use of an experimental scramjet propulsion system or at least to test an experimental scramjet propulsion system—you had the stage set for the plateauing of hypersonic research.
In the 1970s, we had two opportunities to reinvigorate our hypersonics research. One was a program called the National Hypersonic Flight Research facility, which would have built on lifting-body experience to give us a manned hypersonic demonstrator up to about Mach 7. And the second was in support of the space shuttle. That was a proposal by a group of engineers within NASA at the Dryden Flight Research Center to develop a subscale shuttle that could have been flown out to Mach 5 to 6 to collect reentry data in support of the shuttle program. That would also have given us the ability to use that vehicle at some point for plain old hypersonic research, to evaluate materials, systems, propulsion concepts—things of that sort. But when we turned our back on that, and the bills started to come due to attempt to meet the anticipated launch rate for the space shuttle, we simply didn’t have the money. And so the next big step, the NASP, had its own challenges.
A&S: Was the X-15 data used in that X-30 program, the National Aerospace Plane?
Lewis: It’s easy to bash the X-30 program. They spent a ton of money, and there’s been a bit of revisionist history, of people looking back at the X-30 and saying "Oh we got all this great stuff. We got new materials, we got this, we got that." The reality is the X-30 was very much the antithesis, in my mind, of the X-15. It was "Let’s not do a logical, reasoned science effort. Let’s jump to Mach 25 the first time out of the barn. We’re going to build it, we’re going to hop in, we’re going to fly it, it’s going to work. We’re not going to do any ground testing because we have all the computers we need to simulate anything we’d ever need to simulate." And they were completely wrong. It’s still wrong to this day.
Hallion: There was over-enthusiasm about computational fluid dynamics. It was going to replace all ground test facilities and much of flight test facilities; you could do it all by crunching numbers.
Lewis: We had people saying that the X-30 marked the end of the wind tunnel. We no longer needed wind tunnels because we could simulate everything on a computer. And you can contrast it with work today. We’ve gotten into this mode where we don’t really do envelope expansion. We keep shooting for the Next Greatest Thing.