Objects in orbit appear to move more smoothly than objects on a planet's surface due to several factors:
Lack of Atmospheric Resistance: Objects in orbit are typically outside the Earth's atmosphere or at altitudes where the atmospheric density is extremely low. This means they encounter minimal resistance or friction from the air molecules. In contrast, objects on the planet's surface have to overcome the drag caused by the atmosphere, which can result in turbulence and irregular motion.
Constant Freefall: Objects in orbit are essentially in a state of continuous freefall around the planet. The gravitational force acting on them is balanced by their forward velocity, creating a stable orbit. This state of freefall results in a feeling of weightlessness for astronauts and a smooth, uninterrupted motion. On the planet's surface, objects experience the effects of gravity and various other forces, leading to a more complex and jerky movement.
Higher Speeds: Objects in orbit travel at significantly higher speeds compared to objects on the planet's surface. For example, the International Space Station (ISS) orbits the Earth at an average speed of about 28,000 kilometers per hour (17,500 miles per hour). The high orbital velocity contributes to a smoother motion as objects traverse vast distances in relatively short periods, reducing the perception of abrupt movements.
Larger Distances Covered: Due to their higher speeds and orbital paths, objects in orbit cover larger distances compared to objects on the planet's surface over the same period. This increased distance traveled results in a more gradual and smoother appearance of motion.
It's important to note that even though objects in orbit seem to move smoothly, they are subject to various gravitational influences and orbital perturbations, which require continuous adjustments to maintain their orbits. These adjustments are made using thrusters or other control mechanisms to counteract the gravitational forces from celestial bodies and maintain the desired orbital path.