[EDIT: added some links and fixed a couple typos.]

Since Ryan did this a while ago, the Humans Space Flight Plans Committee is in hearings, and I’m finishing a summer stint at NASA Johnson Space Center, I feel like I have to do this. Five broad reasons for the world – specifically America – to have a robust human spaceflight program:

1. Exploration

Something that a lot of space enthusiasts, and often NASA representatives, forget is that “exploration” is not a reason for human spaceflight in and of itself. We can’t say that we’ll explore space because humans explore to explore and conduct exploration, since exploring is noble and we’ve always explored and we like exploring.

What exploration does is open up new avenues of possibility: in science, commerce, settlement, technology, you name it. First, it presents us with novel challenges to overcome, which we otherwise might not have been presented with. In overcoming those challenges, we may develop solutions with other applications or find that we improve our society in unexpected ways. Second, we may discover unexpected solutions to unrelated problems as we explore. We may find that our efforts have uncovered things with direct applications back home, or that we learn of a wholly unknown branch of science. Third, exploration broadens the vision of society. Polynesians likely did not think of themselves as bound to localized islands, but as seafarers linked by common bonds. Europeans certainly had a different set of national priorities before and after the circumnavigators, conquistadores, and colonists set out. Americans practically have the phrase “Westward ho!” engraved in our genes, as our national history has always been written with an eye to the horizon. And everyone on Earth began to view our planet differently after Apollo sent back pictures of our tiny blue marble against the fathomless black backdrop of interplanetary space. These shifts in vision allow societies to consider expanded possibilities: previously “outside-the-box” thinking becomes more accepted.

2. Science

Science can be done in space by both humans and robots. But robots come nowhere near matching the perceptive ability, flexibility, problem-solving skills, broad knowledge base, ability to shift focus, and physical maneuverability of a human being. I would also argue that a human scientist’s sense of wonder would be an asset on Mars or beyond.

Telepresence is not a solution to all these shortcomings of robots. The communication lag between Earth and any robotic mission means that none of these human abilities are truly applicable to a robotic mission. In the NPR coverage of Apollo 11’s 40th anniversary, one interviewee quoted Steve Squyres, principal investigator on the amazingly long-lived, result-producing, panorama-photographing, and generally spunky Mars Exploration Rovers Spirit and Opportunity as saying that he timed how long his grad students took to complete a comparable set of tasks to what one of the MERs can do in a day. The average result: 45 seconds. (I’ll have to ask some of them and confirm that.) That means that in an eight-hour workday, a human geologist could perform 640x as much work as a MER does in a full day. I daresay the actual value of the work would be higher, as well, due to the human’s enhanced ability to observe, consider context, and prioritize – not to mention a human’s much better walking speed over rugged terrain!

Without the manned landings on the Moon, we would not understand the origins of the Earth-Moon system the way we do now. Practically no scientists suspected that the Moon was blasted from the Earth in a collision with a Mars-sized planetoid before the Apollo missions, thanks to the incredible sample returns from Apollo 15-17. What we understand from those Moon rocks is now a key factor in planetary science throughout the Solar System – from crater-counting age dates to theories of planetary interiors.

There are profound scientific implications if we discover life elsewhere in the Solar System – on Mars, Europa, Titan, Enceladus, or anywhere else. By now, we know that water or water ice exists practically everywhere in the Solar System. If it is indeed true that life can evolve in water ice, then the concept of the “habitable zone” of Sol must be broadened from a thin belt around 1 AU down to Mercury’s orbit and out to the Kuiper Belt. The discovery of extraterrestrial life is, in my opinion, an inevitability rather than merely a possibility. What will make extraterrestrial life so wonderful, so awe-inspiring, and so profound is that this life will likely either be similar to Earthbound life, or radically different from it. If it is similar, we must ask ourselves how life could evolve to a similar end state in the dramatically different environments of Earth and [fill in the planetary body here], and what that means for our understanding of how life came to each of those locations. If it is different – “life as we don’t know it,” as we might find on Titan or in a gas giant’s atmosphere, or even in a quasi-relatable place like Europa’s ocean – then our scientists will have whole new fields of biology to investigate, likely with all sorts of opportunities for cross-pollination and shared understanding with the field of terrestrial biology.

Finally, there are some locations out there at which some sciences might better be  pursued than on Earth. Geology is best done in the field, but that’s only one discipline. Plasma physics would likely benefit from a research station near a boundless source of plasma – the Sun. Fluid dynamics would benefit from a research station with access to the extreme temperatures and pressures of a gas giant. Astronomy would certainly benefit from large orbital telescopes. Particle physicists might be able to do interesting things in a deep-space vacuum, or with a supply of high-energy particles from the Sun, Jovian magnetic fields, or cosmic sources.  Novel experiments from physics to chemistry to biology could be conducted in a zero-gravity environment. And this is definitely not an exhaustive list, this was just from the top of my head. Put the scientists where the science is, I say, because of the improvements to reaction time and situational awareness.

3. Technology

Space exploration has always and will always require new technologies. These technologies directly impact our lives on Earth – if not immediately, then in the future. Microprocessors, precision electromechanical devices, CAT scans, lightweight alloys, kidney dialysis, golf clubs, lithium batteries, swimsuits…all these things have been developed or evolved under the influence of human space exploration. Before Gemini, American manufacturers could not reach the minute tolerances required for spaceflight – and now they can. The Hubble Space Telescope kicked off a burst in development of optics and corrective software, resulting in innovations in medical imaging. The Gemini program also had the first computer-guided reentry – technicians had to develop a computer small enough and precise enough to trust with a human life at a time when “computer” meant a room stuffed with vacuum tubes. (Ask yourself if your cell phone or iPod would exist at all without that challenge.)

As we develop the technologies for space exploration, our space capabilities grow in response. The more we do in space, the more we can do, and keeping people intimately involved in the process accelerates that development and its results. Furthermore, as our capabilities in space grow, we bring that development right back to Earth.

This requisite improvement in technology from human spaceflight also relates to my opinion that the current Constellation program actually stifles innovation: its explicit mandate to use as much existing technology as possible not only fundamentally limits the program’s capabilities and development, but it denies one of the most tangible (read: best for future funding) reasons to pursue space exploration.

4. Inspiration

To paraphrase Neil deGrasse Tyson, there are three ways to get a society to do great, expensive things: put that society under threat (military), promise great returns on the initial investment (economic), or appeal to their sense of wonder. (Tyson said “religion” for the last one; I’ll expand that a little for those of us who think that there isn’t actually a god who desperately wants us to build megachurches.)

Two of the three worked for the Apollo missions: the American people were convinced of an impending military threat from the Soviet space program, and the accomplishment of putting men on the Moon awed the population. While the military-industrial complex was necessary for much of the industrial effort and technical advancement in the course of the Moon landings, I would downplay the military aspect of the Apollo program, for two reasons. First is that we proved that we could land people and equipment on the Moon with Apollo 11, but then we kept going back, with the explicit goal of science. The military could have cared less after the initial proof of concept. Second, and this can be corroborated from many sources, the spectacle of Apollo 11 mesmerized the entire world. This was perhaps the first and only (so far) event to do something like that.

Several people at NASA have told me that, in their experience, foreign citizens view NASA as their space program as well! NASA serves as the single most effective program for uniting nations as human beings. Put the most contentious diplomats and statesmen in a room together, and then have an astronaut walk in; see how many of them argue with him or her!

NASA also crucially serves to inspire study of the difficult technical challenges and scientific disciplines necessary for space exploration; or those fields that result as by-products of space exploration. The opportunity to put people there gives our students incredible motivation to study these disciplines; nobody wants to devote themselves to something if they won’t get to experience its fruits.

In the future, in order to solve the technical challenges presented by our changing planet, we are going to need a highly educated populace, particularly in the sciences, engineering fields, and math. The analysis skills in those disciplines also apply to fields from psychology to economics to diplomatic policy. To put it simply: America needs nerds. The world needs geeks. And to get them, we need to make sure that nerds and geeks are cool. Or rather, we need to make sure that science and math are not nerdy during those phases of education when students’ interests and opinions solidify: middle and high school. In order to do so, we need to relate science and math to those students, and I argue that achieving that relationship requires a human presence in the most technically and scientifically challenging environments and programs. Human spaceflight is, to date, the pinnacle of such programs.

5. Life

To the best of our knowledge, life is the most rare thing in the Universe. Out of approximately 560 known planetary bodies (8 planets + ~200 moons, large asteroids, and KBOs + ~360 exoplanets), only one supports life, to our knowledge. Out of billions of stars, only one supports life, to our knowledge. It must be treasured and protected. Let’s face it, human beings are volatile creatures. And we have the ability to eradicate life as we know it on this planet, several times over. Not a good combination. I’d like to see us take up the challenge of proving Stephen Hawking wrong, and sever our ties to a single biosphere, permanently. Put a self-sufficient colony in space, on Mars, on the Moon, or wherever. Call it a back-up plan.

Of course, there are profound and tremendous implications for our society if we do discover life elsewhere in the Solar System or universe. Every facet of biology, the theory of evolution, philosophy, and theology, would all likely be shaken if and when we encounter extraterrestrial life. If that life is intelligent, then fields such as psychology, economics, and sociology will uncover fundamentally new and different aspects to study as they begin to account for the behavior of creatures with entirely foreign thought processes. Those studies will inform and enlighten our studies of ourselves.

We cannot prove that life does not exist elsewhere in the universe; we can only explore to find it if it does. That exploration will require the thoroughness, observation of context, and adabtability of a human. And if we do ever find communicative life, then we must find a way to relate to it; that also requires a human.