Design News for Mechanical and Design Engineers

Developing reusable space booster rockets and an eventual replacement for the Space Shuttle will carry a big price tag. By spreading the development base for such systems to private civil applications, such as space tourism, the cost burden can be eased.

 Design News: What are the major aerospace technology trends?

Aldrin: There is a movement toward unmanned aircraft for reconnaissance and long distance strike. Pilots may counter that idea with the need for humans to make judgements on the spot. However, as brave as they are, the trend is to take less risk for pilot loss or capture.

 In space, we need to clearly justify the human presence in low Earth orbit by saying it’s to specialize in human adventure travel or it’s a precursor to sending humans beyond orbit. In other words, say it’s either for, what I favor as soon as possible, establishing a growing potential to develop an adventure travel market, or sending humans to the Moon, Mars, or asteroids. Appropriate government support (in the form of development of low-cost reusable boosters that can be adapted to such use) will make possible a profit and opens up great potential for reduced cost and increased reliability of travel to orbit. Large capacity will be needed to support adventure travel and that can be obtained by heavy lift rockets, not only using the basic rocket payload volume but also augmenting that with the core stage’s empty tanks to build facilities in orbit. We’ll need such large capacity to handle the traffic for those going up for more than an initial flight of 24 hours. On their second trip, people will want to stay five to seven days.

 There is no way you can carve out a separate private-sector financed space transportation system and destination facility. You have to combine their development with things that are needed by the government for its space uses. The next generation Shuttle, or evolutionary boosters leading to one, needs to satisfy NASA’s needs and be capable of modification to carry an economical number of people, say 60 to 80—like the development of the Boeing KC-135 Air Force tanker and the 707 airliner in the ‘50s, they were very similar aircraft.

Q: What do you see as the most dramatic developments in the next five years?

A: I would hope it would be development of demonstrator reusable first-stage rockets that point the way to multiple use configurations of a medium-lift flyback booster fueled by kerosene. They would have applications on present expendable launch vehicles and would support launch of crew transfer vehicles to Earth orbit, augmenting and gradually replacing the Space Shuttle in this function. We have to replace the Shuttle with a third-generation horizontal takeoff vehicle (being studied for the next ten years) because a full-blown three-stage, fully reusable second-generation replacement won’t be affordable.

 If that third generation doesn’t pan out (depending on the development of airbreathing engines that have to be turbojet, ramjet, and scramjet all in one), and we still have about ten years life left on the Shuttle, then we can evolve these medium boosters into flyback boosters for Shuttle use, replacing the solid rockets. This flyback booster can then also serve as a next generation launcher.

 If we are going to fly the Shuttle for 20 more years, then I want to move toward accepting that we can put a container in the cargo bay for adventure travelers—accepting the risk that in the event of a bail out of the crew up front the potential to save the passengers is significantly diminished. However, even the chance of the crew getting out and surviving is a small probability anyway.

 Q: Could a Shuttle replacement be unmanned?

A: We may want an unmanned cargo delivery system because of the simplicity of its mission of delivering cargo someplace and returning as much of the expensive delivery “hardware” as possible. But if that vehicle is so reliable, why not put a crew in there anyway? That vehicle could even be an adaptation of a crewed vehicle. But the primary replacement for the Shuttle should be to deliver a human crew to low Earth orbit for NASA missions and, with a modification of it, to deliver passengers.

Q: What is most critical to sustain our space technology growth and leadership?

A:  We need an inspired and enthusiastic workforce to develop the creative, innovative ideas to improve our space effort. We need a more educated public as to the realities and attractions of human spaceflight. They need to understand it much more, but it needs to be put in front of them and made available. You can do that through multiple, credible lottery selections for spaceflights. It’s going to be very expensive if you have to buy your own ticket. You have to have a system for selecting people other than just the wealthy, because taxpayer money has been expended in development of a dual purpose NASA/adventure travel vehicle. If limited to just wealthy people, it is not going to be a popular program.

Q: Some Russians recently proposed a joint U.S.-Russian manned Mars mission. What is your view on this?

A: That’s a straw man by the Russians who are exuberant to establish ‘rights’ on a technical concept of a mission. They’re very good at defining what this could be. If they can’t afford it, they will still say ‘It’s our concept, therefore we need to have crew members on the mission.’ Right now, I don’t think they can afford the 30% they said they’d offer. And there’s not enough interest in the two countries to work on this now.

Q:  Would there be benefits in returning to manned lunar exploration?

A: That’s premature. We don’t have an economic return and there isn’t political support without an economic return or a much cheaper access-to-space system and public support that would come from adventure travel. Those have to come first.

Q: If, by some miracle, the NASA budget were doubled, how would you say to spend it?

A: We need to have a multipurpose crew transfer vehicle and a quick adaptation of it into a simple orbital lifeboat for the space station so we can increase the station crew size. As we develop that vehicle we should have long duration Shuttles to stay up there for up to 90 days, so we could have seven people on the station (or perhaps 10 crew members if the Soyuz is used as well) at those times. You could then get a lot more science done.  

Even doubling the NASA budget, we can’t afford the full-blown next generation Shuttle replacement. I’d rather see an evolutionary first stage built and augment current expendable launchers with these reusable strap-on boosters. Then from that we can grow a second or third generation Shuttle. 

There are a lot of other things that can be carried out, science missions and updating the support facilities both at Kennedy Space Center and Vandenberg in California. We have to inspire the workforce, which is aging. We should vigorously pursue protecting the Earth from devastating effects of a random impact from space. We have to develop a planetary defense system by understanding more fully what objects are out there that could possibly impact the Earth—which requires many more telescopes, and even some orbital ones. Then we have to establish and test mitigation or deflection techniques on non-impacting objects so we know what to do to divert the path of a potential impacting object. 

Q:  How would you see the military’s role in future space transportation?

A: The military needs to develop, in conjunction with the demonstrator reusable first stage, a small or medium operational reusable booster to go with varieties of upper stages. This will allow delivering a spaceplane quickly, anywhere in the world, that can do reconnaissance on demand or weapons delivery.

Q: What skills are most valuable for aerospace design engineers today?

 A: It’s no longer just computer skills. It has to be marketing and communications skills as well. Engineers need to write reports and be able to market their ideas.