IS THERE A RIGHT WAY OR A WRONG WAY?
There may be more than one right way. In the latest Aviation Week we see Spacex targeting 100 flights from each reusable booster. That would be a major challenge to the legacy launch providers. Vertical landing is one avenue to that kind of economy. Another one, horizontal launch and landing, has been studied for decades by good engineers, and yet never put in service.
Rockwell proposed the Star-Raker and spent some effort on new ideas. They did a lot of engineering and evaluation. That was a huge vehicle and a huge fleet that was perhaps a bridge too far. The landscape is littered with broken space planes. And still DARPA and private ventures seek to make space from a runway. If they deliver a reusable system with wings it may offer greater reliability, safety, and comfort than vertical lauding.
If Exodus Aerospace has even one contribution, there are many other opportunities available. Finding the right combination may require trade studies. Proving them will require actual flight vehicles, even if they are small prototypes. At this point any serious launch providers need to investigate options for the next generation of space access. Our purpose is not to promote one concept as the only way, but to illustrate possible avenues. Others have illustrated methods of value which should be considered.
Our prototypes are just illustrations to reveal possible direction. With funding all the required disciplines can be employed to identify the actual design. But sometimes a new idea is not the only answer or the best answer. Our prototype P5.31 was a suborbital concept. We chose to model an orbital direction with prototype P7.2. We can return with better ideas for the smaller P5 and P6 designs if we consider what may have value for orbital services.
As we saw with the QuickSat study, getting off the runway and modest fuel consumption is critical. We considered the Concorde wing to aid takeoff, and conservative propulsion choices on P7. When the Lockheed SR-72 was revealed, it may point out other solutions for creating a helpful vortex. As it happens, we may have stumbled on similar opportunities with the earlier P5 design.
The SR-72 shows a “jog” in the wing that may be provided to create that vortex. As it happens, we had a flat wing tip on P5 that may produce the same effect. It also tips downward slightly which may (or may not?) add to lift on takeoff. So now we have two candidates for adding lift by tuning the wings. The Concorde was one example, and the SR-72 may offer a new technique. There are options to evaluate. In the 1940s we compared the elliptical wing of the Spitfire and the laminar flow of the P-51. Our generation can still learn new things about wings today.
The SR-72 also features air inlets that do not avoid boundary layer air. Hypersonic designs may tailor the aircraft shape carefully to contribute to the inlet flow. That is part of the aerodynamic innovation that aerospace is developing…let’s keep them working!
Our earlier P5 chose to take boundary layer to inlets to allow doors to close those inlets during reentry and hypersonic operation. Turbine engines in outboard stations are vulnerable to thermal damage. For our illustrations we lack the information to get this design right, but at least we may start the conversation. After all, Star Trek provoked some new technologies, so put this “science fiction” to work too!
Our P-7 proposed to use “Sabre” type inlets with cones that can close. Will high tech propulsion fit in square or gang inlets better than traditional cylindrical installations? Trade studies may compare the value of each. At least there are some new possibilities that could keep the engineers working.
What our articles may deliver is opportunity: to shave a few ounces of mass and a slightly cleaner flight. What remains is the hard work. Each engineering discipline effects the others and the performance depends on the sum of the best answers. The industry already has markets and customers. The leaders will learn how to serve those customers with real economy and reliability.
The possibility of reusable launch vehicles is coming whether we are ready or not. The opportunity to be competitive or even leapfrog the current reusable designs is available now. We can be sure that options are being explored. The Air Force is aware that we need to work with new space ventures as a source of innovation. They are proposing a space consortium to connect new and old space assets. That may be a good answer for their needs, but private industry may be wise to apply the consortium model to their own business plans.
We know that Boeing and Sierra Nevada have winged orbiters which have and will deliver value. Already ventures are preparing spacecraft for on orbit satellite servicing. How much more could they offer with a fly-back vehicle to return defective satellites? So these two ventures need to deliver their vehicles and payloads; that load which pays the bills. A massive payload fairing is not paying the bills.
Lockheed, Boeing, and Northrop build large bombers, freighters, and hypersonic research. Northrop owns Scaled Composites, which is already building space launch aircraft. Pratt Whitney, General Electric, Aerojet, Spacex, and Blue Origin are exploring innovative propulsion. With all this talent, a new design development is a still daunting investment. Government is sometimes a fickle investor, and often lacks vision. An idea like a space coalition is an encouraging exception to the many cancelled X-plane programs. Perhaps industry needs not wait for government to figure it out. They can do their own consortium if they are truly motivated to compete in the future.
It may not be necessary for traditional aerospace to take the full burden of new innovation. If more than one venture did operate in a coalition, we may see more innovation. United Launch Alliance is already an example of such a collaboration. Can these ventures recognize and mentor innovative new space ventures as well? We don’t know what arrangement Lockheed made with the founders of Xcor, but I suspect they harvested propulsion value without leaving the founders broke.
Small ventures and academia may be able to deliver early innovation, research and fabrication of prototypes. There are small firms engaged in mission analysis, avionics, aerodynamics, propulsion, and test operations now. These may identify value without placing burdens on the major players. Having a mentor’s guidance may improve their operation and execution.
New space investment is gaining a lot of interest that can relieve aerospace builders. If they see the deep experience of major aerospace firms growing new space talent, they may be encouraged. The market is already real, and investors want to own the best tools to serve that market. That opportunity can only grow as it becomes regular and reliable. No one firm has to carry risk as Rockwell did with the Star-Raker. We have help now.
As we have seen, there may be more than one “right way” to deliver the goal. At times the old ideas may become valuable to a new mission. In other situations, new solutions are just waiting for you to put them to work. Our nation needs viable industries and product delivery. We need more eyes on the goal, and ways to share the burden. The first stage of a space mission requires the heavy boosters which deliver the big push. The upper stages may be delivered by the fast thinking next generation of innovation. Apart they cannot make the mission, but together they are a working system.