With the 100th anniversary of the Wright brothers' first flight, projections as to where spaceflight technology might be at the end of this century abound. Whatever the future, Chaikin cautions that some key elements have to be in place before what's possible becomes probable.
What developments do you see happening in the next hundred years? Let me look a little nearer into the future. Fifty years from now we could have human bases on Mars and astronauts building and maintaining giant arrays of telescopes in deep space to search for Earthlike planets orbiting other stars. Throughout the solar system, we'll have robotic probes streaming back live images and data. There could be cities on the moon where astronauts mine helium-3 for use in energy production on Earth. And in Earth orbit there will be all kinds of activity, from tourism to industry. At that point we'd be able to say that humans had permanently taken up residence beyond their home planet—a giant leap in our evolution, which would ensure survival of the human species in the event of a planet-wide disaster, whether due to global war, pollution, or an asteroid impact.
What's needed to realize these developments? The main impediment is the cost of access to low Earth orbit, which at $10k per pound is the same now as during the Apollo era. NASA and industry must work to lower that cost by a factor of 10 to 100 without cutting safety, no matter how long it takes.
How can that be done? It can only be done by embracing thinking outside the box. There are a lot of innovative folks out there thinking about the problem. It might be some multi-stage combination of rockets and air-breathing vehicles. It may be a revival of the old idea for an electromagnetic rail-launched vehicle. Or it might be technology that hasn't been thought of yet. It is safe to say it won't be the single-stage-to-orbit approach, which some people have been obsessed with, but poses some daunting technical problems—like the fact that about 90% of the vehicle weight must be reserved for fuel.
Do we need to define goals for the space program? One problem with the space program since Apollo is that it hasn't had a clearly defined goal, other than to build the next vehicle—build the shuttle, build the space station. We need an overarching agenda for NASA that makes it possible to explore the solar system with both robotic and human missions. Each of the component pieces should be designed within that framework.
How can engineers affect the course of the space program? The answer to that—and how any American can influence the space program—is two words: Presidential election. People who support space need to make their voices heard by the candidates and have space activities put on the national radar screen. We need to have a national conversation on space, and engineers can play an important role in that discussion, because they're the ones who turn the dreams of space exploration into reality.