It’s Election Day in the U.S., and while millions of Americans are heading to the polls, some voters are casting their ballots from a much more unusual location—space.

Astronauts aboard the International Space Station (ISS), orbiting Earth at an altitude of around 400 kilometers (250 miles), are still able to participate in the democratic process despite their physical distance from the planet. But space voting isn’t new—astronauts have been voting from orbit since 1997. Here’s how they do it.

The history of space voting

The history of space voting starts in 1996 when astronaut John Blaha couldn’t physically vote in that year’s presidential race between President Bill Clinton and Bob Dole. Blaha was stationed aboard the now-defunct Russian Mir Space Station, a predecessor to the International Space Station.

Since most NASA astronauts live in Houston, Texas, the situation caught the attention of Texas lawmakers. Just one year later, a new bill signed into law by then-Governor George W. Bush, made space voting legally feasible.

David Wolf became the first person to cast a vote from space in 1997 while stationed aboard the same Russian Mir space station. The change came about after the Texas Legislature passed a bill allowing astronauts to vote electronically. Wolf later commented that although it was just one vote, it made an important difference to him.

“It’s something that, you know, you might or might not expect it to mean a great deal,” Wolf told NPR in 2008. “But when you’re so removed from your planet, small things do have a large impact.”

By 2004, the process was in place for American astronauts aboard the ISS to vote in every U.S. presidential election. The only exception occurred in 2012, when astronauts Suni Williams and Kevin Ford, scheduled for an upcoming mission, had to cast their ballots before leaving Earth. They still voted, just not from space.

How space voting actually works

Astronauts submit an application to their local voting office requesting a ballot. However, instead of a paper ballot or even a standard electronic form, the astronauts’ votes are encrypted and transmitted via NASA’s highly secure communication systems.

NASA encrypts the document and sends it to the ISS via its Tracking and Data Relay Satellite System (TDRSS), a network of specialized communications satellites that provide communications services to many NASA spacecraft. The astronaut fills out the ballot on an onboard computer, which is equipped with unique credentials to ensure security. After the astronaut casts their vote, the ballot is relayed back to Earth using the same satellite system used to send other types of data.

In principle, space voting is similar to regular absentee voting, although the practicalities can complicate things. However, as NASA said in a recent blog post, it’s worth the effort.

“Astronauts forego many of the comforts afforded to those back on Earth as they embark on their journeys to space for the benefit of humanity. Though they are far from home, NASA’s networks connect them with their friends and family and give them the opportunity to participate in democracy and society while in orbit.”

Who is voting from space?

There are four Americans currently aboard the ISS: Don Pettit, Nick Hague, Butch Wilmore, and Suni Williams. Each has had the opportunity to join the 160 million voting Americans participating in today’s election.

“It’s a very important duty that we have as citizens,” Williams said during a call with reporters in September, adding that getting to vote from space, “is pretty cool.”

“NASA makes it very easy for us to [be included in elections], so we’re excited about that opportunity,” Wilmore said on the call, revealing he had just requested an absentee ballot that same day.

Funny enough, neither Williams nor Wilmore expected to be voting absentee.

They were supposed to join the ISS from a Boeing Starliner for just one week, starting June 5. However, the Starliner experienced a series of malfunctioning thrusters and remained docked for three months, while NASA and Boeing tried to figure out what the problem was. Ultimately, NASA decided to return the Starliner without the crew, leaving the two astronauts stranded on the ISS for a few months. The two are thankfully safe and the ISS has enough resources to support them.

Space voting is a testament to democracy

Since David Wolf’s vote from the Mir space station in 1997, every U.S. presidential election has seen ballots cast from orbit. NASA astronaut Kate Rubins, for instance, voted from space twice—first in 2016 and again in 2020.

This tradition of voting from space highlights how far space exploration has come. Just a few decades ago, extended missions into space were rare and often not long enough to span an entire election cycle. Now, astronauts spend months, sometimes even close to a year, aboard the ISS, conducting vital research and international cooperation in space. Their ability to vote from space is a strong testament to the democratic process: even if you’re physically away from Earth, you can still vote and stay connected to democracy.

If research stations on the Moon and Mars become a reality, NASA will need to set up a voting system for them as well. There’s something reassuring about that — but also a reminder of the responsibility we carry as voters.

After all, if astronauts can manage to vote from space, it serves as a reminder to all of us back on Earth that participating in elections is not just a right but a responsibility.