When it comes to space exploration, speed is of the essence. But just how fast can a rocket travel in space? The answer depends on the type of rocket and its destination. For rockets that are designed to orbit the Earth, they must reach speeds of at least 4.9 miles per second, or about 17,600 miles per hour. To completely escape Earth's gravity and travel to another moon or planet, however, they must go even faster, at a speed of at least 7 miles per second or about 25,000 miles per hour.
The record for the fastest manned mission still belongs to Apollo 10, which took place in May 1969. This mission reached a constant cruise speed of about 16,150 mph (26,000 kph). Today, many billionaires such as Jeff Bezos and Richard Branson are trying to build better, cheaper and faster rockets. Conventional rockets are generally designed to reach the speeds needed so that they can go where they need to go and not go much faster. The final model of the spacecraft will require six rocket engines and a standalone rocket called Super Heavy to reach orbit.