Space travel has come a long way since the days of William Shatner's Captain Kirk. International Space Station (ISS) missions, known as expeditions, typically last around six months, with three to six crew members on board from countries such as the United States, Russia, Europe, Canada and Japan. The Spanish-American space traveler Mike López-Alegria holds the record for the longest US mission to date, with 215 days. Former cosmonaut Valeri Polyakov spent 14 months aboard the Russian space station Mir.
However, space travel used to last only two weeks during the existence of the Space Shuttle. A trip to Proxima Centauri, the closest star system to the Sun, would take about 4 years to arrive, considering it is 4.3 light-years away. But for someone aboard a rapidly moving object - whether it's a particle, a train or a spaceship - cosmic distances appear to contract. Currently, the Russian space station Mir is a place where astronauts can stay for extended periods of time and investigate these effects.
At 82 years old, Funk - a longtime advocate for women in space - joined Amazon founder Jeff Bezos on Blue Origin's flight to the edge of space in July. One of the biggest challenges faced by humans wanting to make long-term trips in space is the biological effects of not having Earth's gravity. NASA has been working with SpaceX and Boeing on their systems for over 10 years, transferring knowledge from more than 60 years of manned spaceflight and innovation into low Earth orbit. If a “second” corresponds to a trip back and forth between mirrors, a moving object will need more time for that trip to take place.
Astronauts work in mission control and analyze different techniques and agendas that the group will use in space, help check the programming of the space station and vehicles, create systems and procedures that will be used during spacewalks or mechanical operations. From the perspective of someone at rest, time will seem to decrease significantly for the spacecraft as it gets closer to the speed of light. Just like muscles have to work less to move through space, bones aren't as necessary. On Wednesday, 90-year-old John Glenn became the oldest person in space - a title briefly held by Mary Wallace Wally Funk and formerly held by legendary astronaut John Glenn. On extended space travel, your muscles could weaken so much that it would be difficult for you to stand upright once you return to an environment where you are subject to gravity. From the point of view of a relativistic traveler, they would spend less than 4 years on a trip to any of these stars.
Because the speed of light is a constant for all observers, for someone who moves through space (in relation to stars, galaxies, etc.), time will appear to slow down.