According to CNN, NASA astronaut Kate Rubins will head to space in October as part of the Expedition 63/64 crew. She intends to cast her 2020 vote for president from space, just as she did in 2016. According to the Smithsonian's National Air and Space Museum, astronauts registered to vote in Texas were awarded the right to vote from space in 1997.
Since NASA's Johnson Space Center is located in Houston, most astronauts live in the area and are registered to vote in Harris County, Texas. NASA told CNN that the Harris County Clerk's Office uploads a secure electronic ballot to Mission Control. From there, astronauts can essentially log in to access their ballot, cast their vote and deliver it back to the clerk's office via email.