Friday marked the space shuttle’s swan song, as the Atlantis lifted off from the Kennedy Space Center for the program’s 135th and final flight.

It was President George W. Bush who announced the shuttle’s retirement with his 2004 “Vision for Space Exploration,” which included a moon base and “human missions to Mars and to worlds beyond.” But it was President Obama who put the kibosh on that vision, canceling the moon project and leaving “worlds beyond” in doubt.

“We are retiring the shuttle in favor of nothing,” Michael Griffin, Bush’s NASA administrator, wailed to the Washington Post recently.

Here, as usual, “nothing” gets a bad rap. I’ll be “in favor of nothing” until the advocates of federally funded spaceflight can come up with an argument for it that doesn’t make me spray coffee out my nose.

NASA’s Griffin failed that test in 2005, when he gave an interview to the Washington Post insisting it was essential that “Western values” accompany those who eventually “colonize the solar system,” because “we know the kind of society we would get if you, for example, carry Soviet values. That means you want a gulag on Mars. Is that what you’re looking for?”

Well … is it, punk?

Outside of avoiding the hypothetical horror of Martian gulags, what does the ordinary taxpayer get from the space program?

Not much, says Robin Hanson, a George Mason University economist and research associate at Oxford’s Future of Humanity Institute: The benefits are “mostly like the pyramids — national prestige and being part of history.”

Space partisans often point to the alleged technological breakthroughs that come from solving hard problems like keeping humans alive in an environment never meant to sustain them.

But, as Hanson points out, you could get similar technological boons from any ambitious project you convince the feds to spray money at — whether it’s robot butlers or floating cities. If we wanted to, we could surely “find other projects with larger direct payoffs.”

The argument for federally funded spaceflight ultimately boils down to “spacecraft as soulcraft,” the quasi-religious notion that, as Post columnist Charles Krauthammer puts it, we go “not for practicality,” but “for the wonder and the glory of it.”

Space must be an alluring muse indeed, given that it makes Krauthammer, normally a hardheaded neoconservative, sound like a yoga instructor gone lightheaded during a juice fast.

He calls space skeptics “Earth Firsters,” deaf to “the music of the spheres.” Apparently there’s nothing more “isolationist” than wanting to stay on your own planet.

Krauthammer’s obsession makes sense, in a way, since federally funded spaceflight is the quintessential neoconservative project: a giant, wasteful crusade designed to fill Americans’ supposedly empty lives with meaning.

Sorry, Charlie: The public’s not buying it. A 2010 Rasmussen poll showed that more Americans think private enterprise should pay for space exploration than think government should fund it.

By nearly 2‑to‑1 margins, they also oppose sending federally funded astronauts to the moon or Mars. As far as Americans are concerned, space is the ultimate “bridge to nowhere.”

It’s true that, with a $1.5 trillion deficit, NASA’s $18 billion isn’t what stands between us and our fiscal day of reckoning. But every little bit counts, and this is the rare cut that won’t make the public squeal.

Moreover, there’s a matter of principle at stake here. The threat of force lies behind every tax dollar the government collects. You might demand that your neighbor help defend us against a foreign invader — but would you really hold a gun to his head to help him appreciate “the music of the spheres”?