In 2033, NASA and China plan to send the first crewed missions to Mars. These missions will launch every two years when Earth and Mars are at the closest points in their orbits (Mars Opposition). It will take these missions six to nine months to reach the Red Planet using conventional technology. This means that astronauts could spend up to a year and a half in microgravity, followed by months of surface operations in Martian gravity (roughly 40% of Earth gravity). This could have drastic consequences for astronaut health, including muscle atrophy, bone density loss, and psychological effects.