In the lead-up to the launch of the last space shuttle, "Atlantis", I've been seeing a number of articles on the general theme of an era ending. This week's Economist went so far as to suggest it marks the "End of the Space Age." I sincerely hope they are wrong, and not just because I have followed the US space program avidly since before the first moon landing, but also because of my primary focus on energy. Most of the resources of the solar system, including most of its energy resources, lie outside the earth's atmosphere. To choose a relevant example, space solar power (SSP) might not contribute significantly for decades, but it still looks like an important option for ensuring that energy limits don't constrain our long-term prosperity after the ages of oil and coal wind down.

One presentation that I still recall vividly from the many meetings involved in the economic review of NASA's "Fresh Look" approach to SSP in the 1990s, and from my time on NASA's oversight committee for SSP, dealt with the crucial role of a low-cost, high-frequency launch system in putting the components of solar power satellites into orbit affordably. Even then, it was clear that the current shuttle was not that system. It was equally clear that the traditional alternative of disposable rockets couldn't come close to the $ per pound-on-orbit threshold required. He was proposing a second- or third-generation system using unmanned reusable cargo vehicles that would land like airplanes. This was before the recent advances in drone aircraft.

I wonder what that scientist would recommend today. Perhaps he would build on some of the private spacecraft designs currently under development, such as those of SpaceX, Orbital Sciences and XCOR. However, assembling a solar power system over dozens or hundreds of launches involves very different requirements than taking tourists into space or sending astronauts back to the moon or on to Mars. In any case, without reliable access to space--traveling as passengers on Russian vehicles using a 50-year-old design doesn't count--the benefits of space will be limited to capabilities like the communications and remote sensing of today's satellites. Those are impressive enough and have transformed our world and our view of it, but they can't supply us with the concentrated energy to power cities or industries.

During the space shuttle program's 30-year history, shuttle crews accomplished extraordinary feats at tremendous risk, and sadly some of them paid with their lives. It's interesting to contemplate, as a noted space commentator did this week in Technology Review, whether the right shuttle design was chosen in the early 1970s, though mainly from the perspective of what it might tell us about what our next steps in space should be. I'm as intrigued as anyone by the prospect of resuming manned exploration beyond earth orbit, but it's hard to square the cost of that with the deep cuts that must be made elsewhere to set our financial house in order. A serious examination of the techniques and hardware necessary to deliver space resources for use on earth--now that it wouldn't have to fit an existing shuttle's capabilities--could provide a suitably pragmatic focus for NASA in the current environment.

I have a hunch that a goal of obtaining non-polluting energy from space would go a lot farther towards galvanizing the necessary public support for NASA than the next planetary mission--which incidentally might be easier to construct with the capabilities that a more nuts-and-bolts effort might create. Either way, while it's nice to look back at past achievements, I'd much rather be looking ahead to the accomplishments of the next era in space.