This really depends on what you mean by space. If you just want to orbit the Earth, you must reach speeds of at least 4.9 miles per second, or about 17,600 miles per hour. However, if you want to completely escape Earth's gravity and travel to another moon or planet, you must go even faster, at a speed of at least 7 miles per second or about 25,000 miles per hour. In essence, the ship resides within a piece of space-time, a “warp bubble” that moves faster than the speed of light.
Called the Albierre thruster, it consists of compressing the normal space-time described by Einstein's physics in front of a starship and, at the same time, expanding it from behind. New NASA ships that could jeopardize the Apollo 10 speed record will continue to rely on tried and tested chemical rocket propulsion systems used since the first space missions. Speculative dangers could also arise if humans manage to travel faster than light, either by taking advantage of gaps in known physics or through paradigm-breaking discoveries. However, producing antimatter in useful quantities would require specialized next-generation facilities, and the envisaged spacecraft would face many engineering challenges.
However, shortening travel times would mitigate these problems, making a faster approach highly desirable. The best argument for powering fast spaceships is antimatter, twice that of normal matter. Undoubtedly, micrometeoroids are not the only obstacle to future space missions, in which higher human travel speeds would probably come into play. At several hundred million kilometers per hour, every speck in space, from lost hydrogen gas atoms to micrometeoroids, in effect becomes a high-powered bullet that hits the hull of a ship.
In reality, the speed of rotation around the Earth also depends on the altitude above sea level, and a person who is on the top of a mountain at the equator travels more than 1,660 kilometers per hour (since he has more to go with each revolution). However, assuming that we can overcome the considerable technological obstacles to build faster spaceships, our fragile bodies, mostly made of water, will have to face significant new dangers associated with traveling at such high speed. These G-forces are mostly G benign from front to back, thanks to the intelligent practice of holding space passengers to seats facing their direction of travel. He and his father roughly estimated that, barring some kind of conjectural magnetic shielding to deflect the deadly hydrogen shower, starships could not go more than half the speed of light without killing their human occupants.
Therefore, to achieve significantly faster travel speeds for humans heading to Mars and beyond, scientists recognize that new approaches will be needed.
