One of the biggest things holding us back from exploring the universe is that it takes years to traverse the huge distances between planets.
It would take close to 165,000 years to reach our closest neighboring star using the space travel technology we have today.
Engineers are currently developing ion propulsion systems that will help pick up the pace, but space travel technology could have ended up on a very different path about 60 years ago, according to an interview with famed physicist Freeman Dyson.
Beyond his incredible achievements in mathematics and physics, Dyson has always been a space enthusiast. He and a handful of other physicists were recruited by General Atomic in the late 1950s to develop a unique kind of spaceship propulsion.
Simply put, the idea was to drop a bunch of atomic bombs behind a space ship and ride the momentum from the blast.
They called it nuclear pulse propulsion.
"So we would launch the ship into space — bomb, bomb, bomb, bomb, bomb — going up about four bombs per second," Dyson says in the interview.
This crazy idea was called Project Orion and this was its spacecraft design. It would have been able to carry 100 tones and eight astronauts. The left half of the image shows the vehicle that would launch the spaceship. The right half shows a loft that would lift the aircraft high into the atmosphere before the nuclear propulsion started:
The payload section is at the top of the spaceship. The bombs would drop from the "pusher" end.
Its competition was the more traditional chemical rocket propulsion being developed by NASA's Apollo moon program.
Rockets won, and a chemical rocket is what ended up taking Neil Armstrong and Buzz Aldrin to the moon.
The simple absurdity of dropping a trail of nuclear bombs is a big reason Project Orion failed. Still, the physicists who worked on the project were convinced it could be harnessed and turned into an extremely powerful propellant. Dropping bombs behind a craft would simultaneously produce a huge forward thrust and the exhaust would leave the engine very quickly. It's difficult to make an engine propellant that can do both.
The physicists had their sights set on Mars, then Jupiter and beyond. Dyson took the dream farther and wrote a paper about how nuclear pulse propulsion could be used for interstellar travel.
"And we intended to go ourselves," Dyson said.
Project Orion even built prototypes. Though thankfully they used chemical explosions and not nukes in the tests.
Nuclear pulse propulsion could have translated into fast and cheap interplanetary travel. It quickly lost public and political support though because of the dangers of nuclear fallout that would come from dropping that many bombs in succession.
Check out the full interview with Dyson: