These past few days, it has felt as if the whole world — or at least my nerdy corner of it — has been obsessed with Pluto.

Many tuned into a livestream at some point Tuesday to watch scientists wearing polos and sitting at laptops watch another computer screen, which eventually flashed some of the clearest images ever of the dwarf planet on the outer edges of our solar system. Articles about Pluto have dominated The Washington Post's Web site this week, and at least one space policy expert tells me space news is routinely among the most-e-mailed stories on the New York Times Web site.

But the truth is, space exploration has never really been all that popular with Americans. Even during its heyday when men were walking on the moon, it was controversial.

Polling we found doesn't go all the way back to the Apollo missions of the 1960s and mid-’70s, but Americans are about as interested in space exploration today as they were in 1979, when the National Science Foundation began asking. According to the General Social Survey, in 2014, 22 percent of the public said they were very interested in issues of space exploration, 45 percent were moderately interested and 33 percent not at all. Those numbers are about the same from 1979, give or take a few percentage points.*

Americans' interest in space only briefly cracked more than 50 percent when Neil Armstrong and Buzz Aldrin took one giant leap for mankind on the moon, said Casey Dreier, the director of advocacy for the Planetary Society.

“The mistake we make, thinking about NASA in the past, is that it was ever driven by the public,” Dreier said.

It's easy to gloss over the Apollo days as feats of scientific achievement that rallied America during tough times abroad, with patriotic parades for heroic astronauts attended by Vice President Lyndon B. Johnson and an expensive program cheered on by President John F. Kennedy. But there were also protests and a strong contingent of people who distrusted the space program, said Scott Pace, the director of George Washington University's Space Policy Institute.

Skeptics saw the space agency as part of a military-industrial complex; the rockets that launched astronauts out of the atmosphere were the same technology for firing missiles at the SovietsIt also didn't help that Kennedy funded the space program as a sort of psychological and technological battle with our Cold War enemies.

“What has really driven space policy historically — particularly with the Apollo missions — was national security interests,” Dreier said.

Plus, it was all too easy to turn eyes upward to see rockets that cost an average $4 billion a year shooting up into the sky and turn eyes back home to see hoses of water shooting at black Americans and civil rights protesters, or young men dying in Vietnam, and wonder if it's worth all that money.

“They would say, ‘Okay, here are all these problems, and yet here's this really big visible government program,’ ” Pace said. “ ‘Why are they spending money on that?’ ”

In 1973, during the final years of the Apollo program, 59 percent of Americans thought the nation was spending too much on its space program, according to a General Social Survey poll.

Even though space exploration's popularity hasn't changed much over the decades, our willingness to spend money on it has. In 2014,  a record low of 25 percent said we're spending "too much" on space and a record high 23 percent said we spend "too little."  A 42 percent plurality now say we spend "about the right amount."

But as our own Philip Bump points out, "about the right amount" is less in real dollars today than 1991, when a postage stamp was released of Pluto as a bland sphere, with the words "Pluto: Not yet explored." (Part of the reason is that space travel, especially unmanned flight like the New Horizons craft that zoomed by Pluto this week, has gotten cheaper. And NASA has suffered budget cuts along with every other federal agency.)

All this means that NASA -- which is consistently among Americans' most popular public agencies (our feelings about space are complex) -- has never relied on public support to boost its program.

Sure, it spends money to improve its image and inspire future explorers. But winning over you, dear reader, has never really helped NASA pay its bills.

* A note about the poll here, from our polling research team: The General Social Survey was funded primarily by the National Science Foundation and conducted by NORC at the University of Chicago through in-person interviews with a random national sample of U.S. adults. The 2014 results for questions on space are based on 1,238-1,271 interviews and carry a margin of sampling error of plus or minus 3.5 percentage points. Data were analyzed by The Washington Post.