SpaceShipOne Presentation

[Wayne Hicks]

I had the pleasure of listening to Doug Shane discuss the results and lessons learned from the SpaceShipOne flight test program. Doug is the Director of Flight Operations for Scaled Composites, and was the first engineer hired by Scaled when it opened for business in 1982. There were no earth shattering revelations, but I enjoyed some insights not already covered in the various news reports and documentaries.

 

I’ll try to summarize:

 

Scaled’s normal modus operandi was to prototype at least one new design a year, mostly light GA types. But Burt got bored and was looking for a new break-through challenge - space. First concept was air-launched rocket from Pegasus with capsule separation and parachute recovery in the ocean. But risks, complexities, and costs drove the concept to a now-familiar air-launched airplane. Burt was really after the root-ordered, fundamental system that was robust and inherently risk-reduced. Realize that as of 2001, only 4 manned suborbital flights had occurred -- two Mercury flights and two X-15 flights.

 

White Knight was built because Proteus wasn’t big enough. White Knight used engines from the T-38 Talon. Flameouts were common.

 

SS1 was designed extensively with finite element analysis and CFD (computational fluid dynamics). SS1 had an initial tail stall problem. Scaled mocked up the tail section and used its version of a wind tunnel -- a forced beam balance installed onto a Ford F350 pickup truck driven up and down the Mojave runway at 85 MPH -- to solve it.

 

Scaled built a fixed base simulator in-house. X-Plane was used to drive the out-of-window views. They conducted integrated simulations between the pilots in the fixed base and the controllers in the control room.

 

SS1 was prone to rolling in the boost phase. The boost profile used on the first X-prize flight went vertical ASAP after release (to ensure reaching altitude target). However, this caused SS1 to fly uphill at near-zero angle of attack. They found out later that SS1 had no directional stability at zero AOA. It built up side slip, which coupled into roll (180 degrees/sec). Scaled changed the profile on the second X flight to delay convergence of the velocity vector to zero AOA, the roll problem went away.

 

Some other things:

• First rocket powered flight stayed under 30 seconds duration because 30 seconds is the longest duration for amateur rocketry without needing a license.
• SS1 achieved space (>100K meters) on the 100th anniversary of powered flight (12/3/2003). It wasn’t planned that way, it’s just the way the schedule fell. But Burt thought it to be ironic and a good omen.
• Scaled had to do tortoise sweeps prior to each flight. There’s a certain type of desert tortoise indigenous to the high desert. If one was found on the runway, it couldn’t be moved until some “official group” from hours away came up to move it.
• The windows on White Knight and SS1 fogged up a lot. So a “Q-Tip” was carried in each vehicle. The Q-Tip was a broom stick with a towel tied to one end of it.
• The orbital program is still years away, factor of 8 to get into orbit. No clear concept emerging yet, but Burt’s got the thinking cap on.
• No target costs set yet; $200K right now. Hopefully price will drop with success and competition.

I asked two questions:

 

1. How did Burt’s reputation hurt or help with winning over the FAA? Answer: Burt’s reputation is sometimes a double edged sword. The FAA deserves a lot of credit for making the flights possible. They didn’t cut Burt any slack, but they weren’t hard-asses about it either. They really want private flights to continue with minimal regulation. So they were always open to entertaining the “what’s possible” instead of saying “no way”. Scaled did get into hot water when the first X flight went out of bonds, into commercial airspace over Palmdale airport, and over the populated areas. They weren’t happy when the ascent profile was changed for the second flight. Scaled spent a lot of time proving the second profile was safe and would stay in the box.

 

2. What was the weight on the nose at landing and how much did the maple skid wear down? Answer: About 170 pounds on the nose gear. Doug didn’t remember how much the maple was ground down, but it wasn’t much. The maple skid wasn’t changed every flight.

[Jon Matcho]

Thanks for a great write-up Wayne. So does this mean that we can use a maple block instead of a hockey puck for some real protection?