NASA astronauts on Earth and in space have sent in their votes for the U.S. presidential election and encouraged all Americans to remember to cast their own ballots Tuesday.

Space station commander Michael Fincke and flight engineer Greg Chamitoff beamed their votes to Earth on Monday using a secure electronic ballot that was routed to their local County Clerk's Office by Mission Control at the Johnson Space Center in Houston, Texas.

"Today is voting day aboard the International Space Station," Fincke said Monday on NASA TV.

"If we can vote from up here, so can you," Chamitoff said as the station flew 220 miles (354 km) above Earth.

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The two spaceflyers are only the fifth and sixth American citizens ever to vote from space since 1997, when Texas lawmakers passed a state law that allows astronauts to cast ballots while living off Earth.

In addition to Fincke and Chamitoff, only one other NASA astronaut — veteran spaceflyer Leroy Chiao — has voted in a presidential election from orbit.

Chiao, who has since retired from spaceflight, voted in the 2004 election while commanding the station's Expedition 10 mission.

Fincke and Chamitoff said they hoped their example of voting from orbit might encourage American citizens on Earth to exercise their own right to vote.

"It's also to show the rest of our country that [while] I'm so busy up in space, even I can vote, so you on the ground should be able to vote, too," Fincke told SPACE.com before flight. "It's a privilege and an honor, so hopefully we'll get some people excited."

The American public may not need too much of a boost. According to reports from the Associated Press, voter turnout has been high, leading to long lines at polling stations across the nation.

While the station's U.S. crewmembers voted Monday, NASA space shuttle commander Chris Ferguson said Monday that he and his crew made sure to vote early before their planned Nov. 14 launch aboard Endeavour.

"My wife and I stood in line for two hours on Friday night so we could early vote, and I've heard of other crewmembers talking about their experiences for making sure their vote gets in," he told SPACE.com on Monday. "I was really pleasantly surprised by the local voter output."

Ferguson and six NASA astronauts are poised to launch to the space station on Nov. 14 at 7:55 p.m. EST (0055 Nov. 15 GMT) on a 15-day mission to deliver a new crewmember, install gear to help double the outpost's crew size, as well as perform four complicated spacewalks to repair a balky solar array joint.

Unlike Ferguson, who voted in Houston, Endeavour mission specialist Steve Bowen voted in his home state of Florida with an absentee ballot.

He said he was looking forward to the results of today's election no matter which presidential candidate won, be it John McCain (R-Ariz.) or Barack Obama (D-Ill.)

"Every change is an opportunity," Bowen said Monday. "So we'll see what happens."

While Ferguson joked that he only urged his crew to make sure they got their flu shots (to make sure no one gets sick during the mission) before launch, but he was confident his crewmates took time from their busy training schedule to cast their votes.

"I know that all the crewmembers are very interested in where the future of the presidency lies and I'm sure they've all voted," Ferguson said.

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