On the morning of January 28, 1986, a nation of viewers gave a collective gasp. Space Shuttle Challenger, the crown jewel of NASA’s ambitious shuttle program, had just exploded, leaving a telltale trail behind as it disintegrated into thin air. The disaster prompted an outpouring of national grief and raised serious questions about the safety of space flight.

But if it weren’t for a historical fluke, something else may have been lost that day—Big Bird.

A beloved character from Sesame Street may seem like an unlikely passenger on a space-bound mission, but the puppeteer inside the yellow feathered suit, Caroll Spinney, had actually been invited to join the Challenger mission.

“I once got a letter from NASA, asking if I would be willing to join a mission to orbit the Earth as Big Bird,” recalled Spinney in 2015, “to encourage kids to get interested in space.” In another interview, Spinney told the Chicago Sun-Times he was the first civilian asked to go up in the space shuttle.

The story may sound outlandish, but it was true. Taking civilians to space on the newly developed space shuttle, it was thought, was a chance to get the general public excited about space travel (and to justify NASA’s massive spending on the shuttle). In the early 1980s, NASA developed the Space Flight Participation Program to do just that.

The program was designed to launch ordinary civilians into space and included a proposal to send journalists, teachers, and celebrities along as well. Applicants included 42 network broadcasters, including major stars Walter Cronkite and Tom Brokaw.

Spinney never applied for the program, but NASA reached out to the creators of Sesame Street with a proposal to send him into space in the early 1980s. By then, his puppet was a worldwide celebrity. Spinney, who got into puppeteering when he was a child, had been part of Sesame Street since its inaugural season, performing both Big Bird and Oscar the Grouch.

Played by Spinney like a massive, joyful six-year-old, Big Bird became a stand-in for Sesame Street’s viewers, learning the alphabet and discovering the ins and outs of the world right along with them. In space, he presumably would have done the same thing, bringing a dose of wonder and awe to the zero-gravity environment of orbit.

It’s not clear what sank Big Bird’s chances at a civilian spaceflight. Spinney maintains it was the puppet’s 8-foot-2 stance—a size that would have taken up a significant amount of shuttle real estate. In 2015, NASA confirmed that initial conversations with Sesame Street had taken place, but that “the plan was never approved.”

The possible flight of Big Bird was not publicized at the time but surfaced when Spinney took part in I Am Big Bird, a documentary about his life and career.

Spinney didn’t go up on the Challenger, but another civilian did: Christa McAuliffe. The 37-year-old social studies teacher was selected to go to space as part of NASA’s newly minted Teacher in Space program, an offshoot of the Space Flight Participation Program. McAuliffe beat out 11,000 applicants after a rigorous selection process that included briefings and medical exams—precautions that Spinney never underwent.

What happened next was nothing short of tragic. Just 73 seconds after heading into space with a seven-member crew, the Challenger shuttle exploded in front of a national audience and a horrified NASA ground crew. Spinney was watching that day. “We all saw the ship blow apart,” he recalled. “We just stood there crying.”

Though NASA has partnered with Sesame Street for different promotions and even brought some memorabilia from the show onto a 2014 test flight, they never ended up inviting a character into space. Spinney died of natural causes on December 8, 2019, at the age of 85.