Space travel is an exciting and mysterious concept, with the potential to take us to places we have never been before. But how long does it take to get there? It depends on the mission profile and the spacecraft, but generally speaking, it can take anywhere from 6 hours to 3 days to reach the International Space Station (ISS). The Apollo astronauts took about three days to reach the Moon, which is much further away than the ISS, but they traveled more directly and quickly. The farthest distance that people (and animals) have traveled in space is to (or around) the Moon.
However, if we consider other technologies that have gone to space without a person inside, we have gone much, much further. Humans have sent several probes without people to explore and better understand space. These probes are controlled by NASA scientists on Earth. The speeds required for interstellar travel in a human lifetime far exceed those provided by current methods of space travel.
Even with a hypothetically perfectly efficient propulsion system, the kinetic energy corresponding to those speeds is enormous by current energy development standards. In addition, the collisions of spaceships with cosmic dust and gas at such speeds would be very dangerous both for passengers and for the spacecraft itself. Space sickness or, technically, space adaptation syndrome can occur when people find it difficult to adapt to microgravity and may experience nausea, vertigo, or headaches. Interstellar travel is expected to be much more difficult than interplanetary space flights because of the enormous difference in the scale of the distances involved. Wormholes are conjectural distortions in space-time that, according to theorists, could connect two arbitrary points in the universe, through an Einstein-Rosen bridge. The spacecraft itself, as proposed, used a 12,000,000 ton frozen deuterium ball to power 12 to 24 thermonuclear pulse propulsion units. Interstellar travel is the hypothetical journey of a spaceship from one star system, lone star, or planetary system to another.
One problem with all traditional methods of rocket propulsion is that the spaceship would need to carry its fuel with it, which would make it very massive, according to the rocket equation. Based on work carried out between the late 1950s and the beginning of the 1960s, it has been technically possible to build spaceships with nuclear pulse propulsion engines. That is, many different spacecraft propulsion systems have been proposed to give spacecraft the required speeds, including nuclear propulsion, beam-propelled propulsion, and methods based on speculative physics. Therefore, this treaty would have to be renegotiated, although a project of the magnitude of an interstellar mission using currently predictable technology would probably require international cooperation, at least on the scale of the International Space Station. Dr. Geoffrey A. Landis from NASA's Glenn Research Center says that a laser-powered interstellar sailboat could be launched within 50 years using new methods of space travel. If a spaceship could reach an average of 10 percent of the speed of light (and slow down at destination, in the case of human-manned missions), this would be enough to reach Proxima Centauri in forty years.
For example, a spaceship could travel to a star 32 light-years away and initially accelerate at a constant speed of 1.03 g (that is, 1 g of acceleration).The crew of an interstellar ship would face several major hazards including the psychological effects of prolonged isolation; physiological effects due to extreme acceleration; exposure to ionizing radiation from space and possibly from the ship's engines; and physiological effects due to weightlessness on muscles, joints and bones; immune system; and eyes.