The speed of spacecraft varies significantly depending on their mission, design, and destination. Generally, spacecraft travel faster than any vehicles on Earth due to the lack of atmospheric drag and gravity as they move through space.
For example, the Space Shuttle, which operated from 1981 to 2011, would reach speeds of about 17,500 miles per hour (28,000 kilometers per hour) as it orbited Earth. This speed was necessary to maintain a stable orbit and overcome Earth's gravitational pull.
When considering missions to other celestial bodies, speeds can fluctuate greatly. For instance, the New Horizons spacecraft, which flew by Pluto in 2015, traveled at about 36,000 miles per hour (approximately 58,000 kilometers per hour) as it left Earth's orbit. It was one of the fastest human-made objects ever launched at that time.
Another notable example is the Parker Solar Probe, launched in 2018 with the mission of studying the sun. This spacecraft is designed to come extremely close to the sun and will achieve speeds exceeding 430,000 miles per hour (700,000 kilometers per hour) during its closest approaches, making it the fastest human-made object ever.
Interplanetary missions also have specific speed requirements. The Mars rovers, for example, travel much slower once they approach Mars to ensure a safe landing, usually descending at speeds of around 12,000 miles per hour (around 19,300 kilometers per hour), which is drastically reduced as they enter the Martian atmosphere.
Overall, the speeds of spacecraft depend on various factors including their propulsion systems and the gravitational forces of the bodies they are moving towards or away from. Each mission involves careful planning to ensure that the spacecraft reaches its destination efficiently, balancing speed with the need for precise maneuvers during its journey. As technology advances, we can expect even faster spacecraft in future explorations of our solar system and beyond.