SPACE.com -- To Pluto With Postage: Nine Souvenirs Stow Away on NASA Probe

Have you heard the one about the two men looking to launch a probe to Pluto who went to Burger King to find a part for their spacecraft?

It might sound funny, but it's no joke.

To understand how a fast food restaurant almost factored into NASA's first mission to the last planet, you need to know a bit of the history behind New Horizons, which just recently marked 1000 days on its nine year flight to Pluto.

"New Horizons was a nuclear launch," explained Dr. Alan Stern, New Horizons' principal investigator, of his probe's plutonium-powered battery. "Those are rare. There are a lot preparations for safety's sake, but they also do require all major stakeholders being briefed and in agreement we are ready to go."

"After the federal government had given its approval, the state of Florida had to give its approval, so then-Kennedy Space Center director, whose name is Jim Kennedy, and I drove up to Tallahassee one day to see Governor [Jeb] Bush, who was then-governor," recalled Stern of his road trip on Nov. 22, 2005.

Stern described what happened next in an interview with collectSPACE.com:

"On the way to see the governor - it was a long drive, I think it may have been three to four hundred miles - we got to talking about what we might do to get him a little more personally interested in the mission, other than just invite him to the launch," said Stern. "We came upon the thought, why don't we fly a state quarter of Florida?"

As Stern reasoned, they would launch from Florida, some of the parts of New Horizons had been built there and the state quarter just happened to have a space theme. They both liked the idea a lot but upon searching their pockets, came up empty for a quarter to illustrate their point to the governor.

So, at a small town in the panhandle of Florida, they went to a Burger King.

"We tried to find a state quarter in their cash registers. We had their entire staff looking," Stern shared. "It was a pretty surreal scene. The entire time I was thinking, 'Here are these 18- and 19-year-old, minimum wage folks rifling for a quarter that's going to fly to the Kuiper belt."

Not that the restaurant's employees knew of the reason behind their search. "Jim and I sat there and said, 'Should we tell them?' And I was like, 'Nah, it's too involved. They wouldn't believe it if we told them.' We were just a couple of guys with a coat and tie on, stopped in a van."

Unfortunately, despite their best efforts, the Burger King didn't have a Florida state quarter to offer them and as they didn't have the time to stop at every other fast food joint along the way, Stern and Kennedy almost forewent flying the quarter.

"Toward the end of the briefing, I mentioned to [Governor Bush] that we really wanted to fly a Florida state quarter but couldn't come up with one and it was due to our poor planning because we had only thought of it today," Stern recounted. "And he said, 'Well, I've got plenty!'" and with that ran out of the room and when he came back, he had a roll of the quarters. "He said, 'Fly these!'"

Stern accepted the roll from the governor, but explained he could only fly one. The others would be distributed to team members as a souvenir of the mission.

Less you think however, that the quarter flew simply as a gesture to the governor, it served a bona fide purpose on the spacecraft.

"For spin balance, we need to add a number of kilograms to various places [on New Horizons]," explained Stern. "We knew this was the case because the moments of inertia of the spacecraft and the dynamical properties of it, that we would have to trim it out down to literally the grams-level with balance weights. Of course, we had a whole variety of big ones and little ones; you start off with adding a kilogram here and a kilogram there and you end up getting smaller and smaller weights in various places until you're done. We used the coins to that purpose," he said.

"Since we needed a counter balance to [the Florida state quarter], we decided to fly a second state quarter. We picked Maryland because that is where the spacecraft was built. And because we had so many people back in Maryland at the Applied Physics Lab and at Goddard, it was easy for someone to ship us a quarter really quick."

The story continues at collectSPACE.com with the history behind New Horizon's missing message plaque and the 1991 postage stamp that served as the spacecraft team's motivation.

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