I grew up assuming we were going to Mars. That seemed to be an inescapable destiny, because if you could go to the moon then surely you could take the next step, even if it was a rather big one, a bit like Evel Knievel deciding that after a stunt at Caesar’s Palace he should try to jump across the Snake River Canyon. The point is, human destiny seemed to be out there, in space, with all the Star Trek trappings, and if you grew up in the 1960s you saw this as a foundational truth.

I still think this might happen. But when you get older you become wary of assumptions.

You convert your thought patterns to scenarios. You say there’s a 62 percent chance that Scenario 1 will come to pass, and a 23 percent chance that Scenario 2 will materialize, and a 7 percent chance for Scenario 3, and let’s not even think about Scenario 4. (Scenario 4 is the one where the Bat People emerge from the center of the Earth, and it’s game over.)

If you read my story this weekend on NASA you know that the agency has some destination issues. Where to go? What to do? How to do it? Mars is, for the moment, too far away and too difficult to visit with human beings (it’s not the distance, really, it’s the Delta V, and most of all the landing in that thin atmosphere). And the moon has been done.

National policy is to go to an asteroid. For astrodynamical reasons, any human trip to a near-Earth asteroid would take a year. NASA doesn’t have the money or hardware (for example, a habitation module with good radiation shielding) to send astronauts on a year-long trip around the sun. It does have, however, a new rocket in the works, and a new space capsule, both overbuilt for something as mundane as trips to Low Earth Orbit. So where are they going to go? What will we do with these billion-dollar pieces of space hardware? In theory they could be used to return astronauts to the moon, but NASA is not building a lunar lander. They will likely be used for flights around the moon or to the earth-moon Lagrange Point known as L2, a gravitationally stable point roughly 55,000 kilometers past the moon that is an attractive location for space telescopes and future space operations. And then there’s the Asteroid Redirect Mission. We call that Mission Improbable. (Note fancy new story template.) The ARM is in an unfortunate sweet spot: It’s not ambitious enough for those who want a true deep-space, long-duration mission, and yet still awfully hard to accomplish, fraught with technical uncertainties, and hampered by meager budgets.

Back when I was house-hunting, years ago, I spent a lot of time looking at houses that I liked but couldn’t afford. What was worse, though, were the houses that I didn’t like and still couldn’t afford.

Maybe things will change when we see Chinese astronauts on the moon someday. Or maybe the world will come together in an international collaboration that sends humans to Mars. More likely, I think, the future will belong to the entrepreneurs, who can take greater risks and who don’t have to sell their plans to skeptical lawmakers. NASA operates under certain constraints, not least of which is that it has to keep the astronauts alive. It’s also easier to go to Mars if you have no plans to come home. That’s not something you do with civil servants.