A former NASA intern hopes to turn one small stash of videotapes into one giant payday when the only surviving original recording of Neil Armstrong setting foot on the moon will be auctioned.

Gary George was a college student in 1976 when he bought more than 1,100 videotape reels from the space agency for about $218 during a government surplus auction.

“I had no idea there was anything of value on them,” George, a 65-year-old retired mechanical engineer from Las Vegas, told Reuters. “I was selling them to TV stations just to record over.”

And now, he is over the moon at the prospect of the tapes being sold for as much as $2 million when Sotheby’s auctions them off in the Big Apple on July 20.

On the same day in 1969, Armstrong became the first human to walk on the moon shortly after Apollo 11’s lunar module, the Eagle, landed on the Sea of Tranquility.

“That’s one small step for man, one giant leap for mankind,” he famously said in one of three recordings up for auction.

The tapes also show Edwin “Buzz” Aldrin as the two moonwalkers plant the US flag, collect rock samples and talk with President Richard Nixon, among other significant moments, said Sotheby’s rep Hallie Free, who declined to disclose the financial terms with the seller.

George had sold several reels to TV stations for $50 each, but it was not until he was packing his station wagon with tapes to donate to a church for a tax write-off that his dad noticed the three tapes labeled “Apollo 11 EVA,” an acronym for extravehicular activity.

“He was really into the space program and he said, ‘I think I’d hang on to those. They might be valuable someday,’” George told Reuters.

“So, for that very reason, I pulled them out and hauled them around the country for the next 43 years. That’s how come they survived,” he added.

In 2006, NASA admitted that no one could find the original recordings of the lunar landing. Two years later, George was on vacation with a NASA friend who told him he was trying to find the long-lost tapes.

“‘It seems we’ve lost our original tapes of the Apollo 11 EVA,’” George said the friend told him.

“Quite frankly, I was sitting at the table drinking a beer and I said, ‘Well damn, I have those!’” he recalled.

Sotheby’s said the three reels of unrestored, unenhanced and unremastered 2-inch Quadruplex videotape have only been viewed three times since June 1976.

They “transport viewers to the big screen monitor at Mission Control, with images clearer and with better contrast than those that the more than half-billion-person television audience witnessed that momentous July day on their home sets,” according to the auction house.

“We’ve seen how one small step can change everything — but with this recording, you’ll see history like never before.”