It took 400,000 people and one felt-tipped marker to get astronaut Neil Armstrong from Kennedy Space Center to his historic moon walk 50 years ago this month. That’s right: It was one small writing instrument for man, one giant lifesaving marker for Apollo 11.

The felt-tipped marker from Duro Pen Co. that saved the Apollo 11 mission.

In 1969, Larry Sitten was working as the customer service manager at Duro Pen Co., a small, but well-known pen supplier in Brooklyn, when he received a call from NASA’s Christopher Kraft. One of the astronauts had purchased Duro’s felt-tip marker from a department store on the way to work, and NASA discovered that the marker wrote without gravity. “It was because in the marker they had a wadding of cotton material, and the ink is absorbed in that capillary action, taking the ink away,” Sitten says.

Duro’s marker would allow the astronauts to write in space. And so NASA purchased several hundred black felt-tip markers from Duro Pen Co., which then had to be individually numbered for the Apollo 11 mission, according to Sitten.

But what looked like smooth sailing to those watching back home on Earth was actually one pen away from tragedy. When the shuttle landed on the moon’s surface, the circuit breaker’s switch accidentally broke off. “They knocked off the circuit breaker while they were headed out to walk around the moon,” Sitten says. “A broken circuit breaker meant there was no way to start their ascent engine to get them off the moon.”

Quick on his feet, astronaut Buzz Aldrin reached into the pocket of his spacesuit and pulled out the Duro felt-tip marker. “They couldn’t stick anything metal in the circuit breaker, or they would have shorted the entire ship,” Sitten says. “But the plastic tip of the Duro felt-tip marker was nonconductive.” And so Aldrin was able to stick the marker in the circuit breaker and start the switch. Had it not been for that 69-cent marker, the astronauts might still be on the moon.

Today, that lifesaving marker is sitting in a display case in the Smithsonian National Air and Space Museum. But Duro Pen made sure anyone could have a rocket pen. Way before the company’s pens went on the historic ride to space, the company’s line name was already Rocket. Riding high off their connection to the Apollo 11 mission, the company re-released the marker under the name the “Rocket QB2 Astronaut Marker” and sold millions.

Duro Pen wasn’t the only company that profited off Apollo 11. The moon landing captivated millions, and while the public was seeing stars, retailers were seeing dollar signs. Companies quickly jumped onboard the craze, and launched countless Apollo 11-themed products to cash in.

Now on the 50th anniversary of the momentous landing, Apollo 11 is still sending companies over the moon. From apparel and jewelry to toys and food, products commemorating the anniversary abound. For youngsters and the young at heart, NASA worked with toy manufacturer Lego to release a collectible model of Apollo 11’s Eagle lunar module. Included in the set is a replica of the moon’s surface with craters and astronaut footprints and the American flag planted on the moon by Aldrin and Armstrong. This will be the sixth Lunar Module model released by Lego; the company released its first set in 1975.

For the lover of space and all things luxe, time is running out to grab a limited-edition Speedmaster from Omega’s Apollo 11 50th Anniversary series. The $34,000 watch is a tribute to the 50th anniversary of the Apollo 11 moon landing. The brand’s iconic Omega Speedmaster watch was worn by astronauts Buzz Aldrin and Neil Armstrong during the Apollo 11 mission.

Worried about getting stuck on the moon yourself? It may not be the superhero Duro pen, but Fisher Space Pen Co. (asi/54423), whose pens were also on the Apollo 11 mission, has released a $700 limited-edition pen that comes with a commemorative coin and display case with a plaque that says: “Houston, Tranquility Base here. The Eagle had landed.”

And then there’s one that everyone can enjoy: moon cookies. Not really, but Nabisco’s limited edition marshmallow moon Oreos are close enough. The out-of-this-world cookies come in a glow-in-the-dark package and are stuffed with purple marshmallow crème.

Lego released a collectible model of the Eagle lunar module.

Fisher Space Pen Co. has released a limited-edition pen and commemorative coin for the 50^th anniversary of the moon landing.

Oreo has released a limited-edition “marshmallow moon” flavor to coincide with the Apollo 11 anniversary.

A limited-edition Omega Speedmaster watch, the style worn by Buzz Aldrin and Neil Armstrong on the Apollo 11 mission, is being sold for the anniversary.