Bill Nye’s Planetary Society is developing spacecraft powered by solar radiation. (Lindsay Mann/Structure Films)

Bill Nye is immediately recognizable to an entire generation that grew up with his wacky experiments and Science Guy persona.

But what’s behind the lab coat?

It turns out he’s a man focused on fighting science denial. “Bill Nye: Science Guy,” a POV documentary that premieres on PBS Wednesday, follows him as he tries to carry out this seemingly impossible mission.

Filmmakers David Alvarado and Jason Sussberg delve into Nye’s past, his personal life and his current obsession with countering climate-change deniers and creationists who don’t believe in human evolution. It’s a controversial strategy among scientists, some of whom think that it doesn’t make sense to shine a spotlight on anti-science views. But Nye disagrees with that viewpoint as passionately as he differs with the deniers themselves.

That makes for good television, and the film should generate plenty of debate about Nye and his tactics.

Nye is CEO of the Planetary Society, a nonprofit founded by his mentor, Carl Sagan. The documentary follows Nye through the launch in 2015 of LightSail 1, a spacecraft powered by solar radiation. The real story, though, is Nye’s struggles to fill Sagan’s shoes. Sagan, who died in 1996, also grappled with science skeptics, and Nye has taken up his work in even more embattled times.

The film is packed with tense moments as Nye confronts figures including Joe Bastardi, a meteorologist and cable-news commentator who denies humans’ involvement in global warming. As Nye and Bastardi spar over the planet’s future, we see their similarities — including their passion, effective use of media and worries about the lasting impact of their work — as clearly as their differences.

Nye’s work is cast as heroic, but it’s also endless. In a dramatic moment, a person attending a Nye-led conversation on climate change abruptly leaves the room when Nye says the majority of scientists agree that humans cause climate change. It’s a reminder that, despite his take-on-all-comers stance toward science skeptics, Nye doesn’t win every battle to persuade deniers they are wrong.