UPDATE: Nov. 2, 2016, 5:41 p.m. EDT This story has been updated to reflect a correction. NASA's Shane Kimbrough has not yet voted and is, in fact, planning to vote from orbit. The information NASA originally provided to Mashablewas in error.

The updated story is below.

When tens of millions of people around the United States head to polling places to cast their votes in Tuesday's presidential election, the only American in space will have already filled out his ballot.

NASA astronaut Shane Kimbrough — the sole American on the International Space Station right now — filled out his (very much) absentee ballot through a special electronic system specifically set up for astronauts on the Space Station, NASA said.

Kimbrough is planning to fill out his ballot and send it back down to Earth sometime in the next couple days, according to the space agency.

County Clerk's offices in Texas can create a "secure electronic ballot" that is sent up to the station for the astronauts by mission control at NASA's Johnson Space Center.

"An e-mail with crew member-specific credentials is sent from the County Clerk to the crew member," NASA said in a statement explaining the process in 2008. "These credentials allow the crew member to access the secure ballot."

Once the ballot is filled out, the crew members send it back down to Earth and the County Clerk's Office records the vote, NASA said.

Astronauts are able to vote this way thanks to a 1997 bill passed in Texas, which allows the space explorers (who mostly live in Houston, where Johnson Space Center is located) to vote while in orbit, NASA added.

NASA's Kate Rubins — who just flew back to Earth over the weekend — used the electronic method to send her completed ballot back to Earth before leaving the station.

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The ballot address was marked "low-Earth orbit," the location of the Space Station, Rubins said.

"It's very incredible that we're able to vote from up here, and I think it's incredibly important for us to vote in all of the elections," Rubins said in an interview.

Casting votes from Mars?

In the future, voting from space could become somewhat more complicated.

At the moment, NASA only flies people to the Space Station located about 220 miles above the planet, but in the future, the agency wants to send humans to explore Mars, a trip that would require them to be off-world for at least a few years.

The space agency doesn't have any specific rules governing how red planet-bound explorers will vote as of yet, but it might happen in much the same way as it does now.

"I don’t think anyone is making specific plans for voting from Mars yet, but I suspect it would work much the same," NASA spokeswoman Brandi Dean told Mashablevia email. "There is a delay in getting communications back and forth, but it’s on the order of minutes, so the current process would still work fine."