A few weeks ago, Icame across an article in the Houston Press about Buzz Aldrin and Mars. Headline: “Buzz Aldrin Says NASA Should Ditch the ISS and Make the Mars Jump“. Aldrin’s statement is hardly anything he hasn’t said before,  but any debate about NASA’s next steps needs to start by discussing a more fundamental question: Why should we go into space at all?

Category 1: Human Spaceflight

Aldrin would probably say something along the lines of “because we as humans are born explorers, and it is the greatest challenge of all to venture out into the great vastness of space.” Human space exploration of the solar system and beyond as the goal of spaceflight has a sizeable contingent of supporters, and plenty of lofty rhetoric to match (think JFK’s famous Moon Speech). Inspirational appeals to our sense of adventure and wonder aside, it is practically true that doing the hardest things we can imagine results in incidental gains in scientific understanding, technological development, national morale/prestige, etc.

Distinct from human space exploration is human space settlement. For some human spaceflight advocates, the goal is not exploration for its own sake, but toward the goal of eventually spreading human settlement from our planet to orbit, the Moon, other planets, and maybe even someday to other star systems. If this is your truly  primary goal, your favored missions are likely to be different from those in the exploration camp. For example, building a permanent human city in Low-Earth Orbit is a far more practical and useful goal than a Mars colony in context, for a number of reasons. There’s the proximity to Earth, for starters, which would allow for far lower mission risk and cost for an equivalent-size settlement, and we’d be able to learn vast amounts of useful information about living well in space before venturing out further.

Category 2: Space Science

But detractors of the first philosophy tend to claim that the incidental advances we get out of human spaceflight are just that: incidental, and nowhere near worth the enormous expenditure required for human spaceflight. If we really want scientific understanding of space and our solar system, then robotic and uncrewed systems can get the job done for orders of magnitude less money. They don’t need oxygen, water, food, and pressure, for starters, and moreover they don’t need to come back.  Purists of this camp see multi-billion-dollar, rocket programs like the Space Launch System (SLS) as astronomical wastes of money, noting (correctly) that the bulk of the cost of such systems goes into making them human-rated. Instead, why not  take all that money and double or triple the number of robotic probes we send out to explore the universe on our behalf?

Category 3: Earth Science

The two camps described above tend to generate the most noise in space policy debates, and it’s tempting to think of them as ends of a linear continuum. However, a third major category of answers to the “Why Space?” question focuses closer to home. Space-based systems are essential to understanding, protecting, and improving life on Earth. Satellites help us understand a whole gamut of Earth-based knowledge, including climate change, weather and storm monitoring, atmospheric and ocean science, forestry land use, navigational and communication systems (such as GPS and the Internet), and even tools that enable sustainable and productive farming and fishing.

So which one should we choose?

As all three of these categories contain worthy pursuits in their own respects, it shouldn’t be surprising that NASA does all of them. (I should add that NASA also does significant and valuable aeronautical research that improves aviation and atmospheric flight around the world, but as this post is entitled “Why Space?”, I am setting this portion of NASA’s portfolio aside.)

It’s no secret that NASA is underfunded, given its wide mandate. NASA’s $19B budget is relatively small by federal standards, coming in at only around half of one percent of total federal spending. The perennial debates over where its missions should be going and what else it should be doing can devolve into fighting over scraps to preserve stability in legacy programs, and the tens of thousands of highly-educated jobs that these programs support.  These debates often miss the big picture.

While few people are arguing that NASA should pursue one of these aims to the exclusion of the others (Buzz Aldrin comes pretty close), the divides in the space community reveal a fundamental disconnect about what people find valuable, if anything, about going into space at all. This mismatch of values means we’ll continuously be talking past each other when it comes to deciding the “best” allocation of NASA’s portfolio. I think a good, public, and reasoned debate over the value proposition of each path would be a healthy thing for the agency, the space community, and the nation.