GETTING OFF THE GROUND
Horizontal launch depends on an aircraft being able to fly from the runway to space. We find that present technologies still come short of doing so. The solution will require some available technologies applied in new ways. But the first step to space, the real booster, is always the investor. To encourage a big risk venture will require a solid technology to validate a solid business plan.
We can look to Elon Musk as a type of the ideal investor. He combines business and technical savvy with a vision for space exploration. I hope he reaches his goals, and I hope we can back him up with alternative solutions and expanding interest in this field of investment. We are depending on Spacex and all of today’s space ventures to pioneer a new industry in a lagging economy.
To reach a target investor like this we need a clear advantage in technology and a good team for our presentation and implementation. I propose to gather methods that have been demonstrated but underused in space applications. We can see a number of proposals and working systems that offer hope for a world beater solution.
Boeing offered an interesting concept that can suggest good directions. http://robotpig.net/__aerospace/tsto.php I like the rocket powered version of their orbiter because hypersonic upper stages could find limited atmosphere at the altitude of second stage operations. It could offer a great speed increase if it stayed low enough though. The biggest challenge is getting speed, often overlooked in airplane boosted proposals. I do plan to offer some improvements for our design though.
A first stage vehicle needs to lift a huge mass of fuel, more like a tanker than a passenger craft. For this a delta wing design can offer a high lift vortex during takeoff. This was demonstrated by the Concorde: http://www.concordesst.com/wing.html This is a common theme in horizontal launch proposals.
First stage vehicles might also take advantage of the fuselage shape for contribution to lift. There are many studies that illustrate flattened and blended fuselage shapes being offered today. These blended shapes may also offer deep sections that can provide structural strength with reduced weight. Increased internal volume can also make the wings part of the solution for containing massive fuel tanks and cargo. http://www.bbc.com/future/story/20121106-radical-planes-take-shape
Our challenge is to identify forms that lend themselves to efficiency in space launch operations. We must escape the perception that wings are a “mass penalty”. For the upper stages an orbiter may favor the minimal wings of a lifting body. These forms are being applied in the X-38, the Dream Chaser, and a few other systems. They have been tested and are still available. http://www.liftingbody.net/PRIME__x-23_.html
A booster stage suffers less reentry trauma and may favor longer wings for efficient climb. I have illustrated model airplanes that suggest in-line staging for aerodynamic advantages. They have been designed around available model propulsion and servos. Now we need a system tailored to real scale hardware. Perhaps we should target an unreal scale that is being considered for a comparison. The Space Launch System proposes to have propulsion for vertical launch. Perhaps a study can project a redesign for horizontal launch. If this is not overkill there is hope for a reasonable vehicle to evolve from downsizing exercises.
Oh this is an unreal study. Using the tank sizes from SLS will produce a massive aircraft. But scaling up my model airplanes indicates that the tanks can be contained in a vehicle not too different in scale from the Stratolaunch vehicles. The trick is to make this scale into an aircraft that will actually fly from a runway with a huge mass and limited wings. Well, they say that with sufficient thrust, pigs fly just fine!
My last flying prototype was overweight with low aspect ratio. Flying on top of a gas powered launcher made a top-heavy combination that was hard to control. Full scale launchers will need a lot of dihedral for stability, which could make the booster a bit over stable without its “pig”. In-line staging will keep the center of gravity low to prevent this issue. We managed a good first flight test so new designs can enjoy a greater margin of safety.
This new proposal will be the mother of all pigs, and it still needs to approach some feasibility. A long process of notional ideas will look at shaving mass and drag from the monster. We will not remove all the barriers to investment though. A world beating system will require investment and infrastructure. I hope to prepare a plan for world beating investors. Stay Tuned!