Final answer:
Due to inertia, an astronaut floating away from the ISS will continue moving away. Without external forces like air resistance or significant magnetic fields to alter their motion, and with the ISS and everything inside in a state of continuous free fall, they maintain their velocity in space. The astronaut can move away from a stationary position through actions that obey the conservation of momentum.
Step-by-step explanation:
An astronaut finds himself floating away from the space station. Due to inertia, the astronaut will continue floating away in space rather than returning to the space station. In the absence of external forces, a body in motion will stay in motion with a constant velocity and a body at rest will stay at rest, according to Newton's first law of motion. There is no air in space to provide resistance, so air resistance is not a factor that would decelerate the astronaut. Moreover, unless the astronaut is near a large magnetic field, magnetic forces are insignificant in this scenario. The gravitational pull of Earth does exist at the altitude of the International Space Station (ISS), but it does not cause the ISS or objects within to fall back to Earth because they are in a state of continuous free fall around the planet, creating an apparent weightless environment.
To move away from a stationary position in the center of the space station, an astronaut can change his momentum by expelling mass or by pushing against an object to utilize the conservation of momentum, which governs that the total momentum of a closed system is constant. For example, the astronaut could exhale sharply, throw an object in the opposite direction, or make a swimming motion to create the necessary reactionary force that would propel them in the desired direction.
Understanding these principles is essential for space missions and the safety of astronauts, as actions in a microgravity environment have different results compared to actions on Earth.