When it comes to traveling through space, the speed you can reach depends on what you're trying to do. If you're just looking to orbit the Earth, you'll need to reach speeds of at least 4.9 miles per second, or about 17,600 miles per hour. But if you want to escape Earth's gravity and travel to another moon or planet, you'll need to go even faster - at least 7 miles per second, or about 25,000 miles per hour. To reach these speeds, scientists have developed a propulsion system called the Albierre thruster.
This system works by compressing the normal space-time described by Einstein's physics in front of a starship and expanding it from behind. This creates a "warp bubble" that moves faster than the speed of light. NASA ships that could potentially break the Apollo 10 speed record will still rely on chemical rocket propulsion systems that have been used since the first space missions. But if humans manage to travel faster than light, either by taking advantage of gaps in known physics or through paradigm-breaking discoveries, there could be some speculative dangers.
To make this possible, specialized next-generation facilities would need to be built to produce antimatter in useful quantities. Shortening travel times would help mitigate these problems, making a faster approach highly desirable. The best argument for powering fast spaceships is antimatter, which has twice the energy of normal matter. But micrometeoroids aren't the only obstacle to future space missions - if humans are traveling at higher speeds, they'll face many new dangers associated with such high speeds.
At several hundred million kilometers per hour, every speck in space becomes a high-powered bullet that hits the hull of a ship. The speed of rotation around the Earth also depends on altitude above sea level - someone standing on top of a mountain at the equator will travel more than 1,660 kilometers per hour due to having more distance to cover with each revolution. But if we can overcome the technological obstacles to build faster spaceships, our bodies will have to face significant new dangers associated with traveling at such high speed. These G-forces are mostly benign from front to back thanks to passengers being held in seats facing their direction of travel. To achieve significantly faster travel speeds for humans heading to Mars and beyond, scientists recognize that new approaches will be needed.
This could involve magnetic shielding to deflect deadly hydrogen showers or other methods that are yet to be discovered.