- #1
rieman zeta
- 10
- 0
why does firing your rocket engines (obviously in the appropriate direction) at perihelion give the greatest velocity excess at infinity?
A powered gravity assist is a technique used in spacecraft navigation to increase or decrease the velocity of a spacecraft by utilizing the gravitational pull of a planet or other celestial body. This is achieved by using the spacecraft's engines to adjust its trajectory as it flies by the body, allowing it to either gain or lose speed.
A powered gravity assist works by utilizing the concept of conservation of energy. As the spacecraft approaches a planet, its engines fire in the direction of motion, increasing its speed. This boost in speed is transferred to the planet, causing it to move slightly in the opposite direction. As the spacecraft continues on its trajectory, it gains momentum from the planet's gravitational pull, effectively using the planet's own energy to increase its velocity.
The main advantage of using a powered gravity assist is that it allows spacecraft to conserve fuel and travel greater distances. By utilizing the gravitational pull of planets, spacecraft can achieve much higher speeds than they could using their own engines alone. This technique also allows for more complex and intricate trajectories, allowing for more precise and efficient exploration of our solar system.
While powered gravity assists are generally considered a safe and effective technique, there are some risks involved. One potential risk is the possibility of a collision with the planet or other celestial body, which could cause damage to the spacecraft. Additionally, the precise calculations and timing required for a successful powered gravity assist can be challenging and any miscalculations could result in a failed mission.
One of the most well-known examples of a powered gravity assist is the Voyager 2 spacecraft's flyby of Saturn in 1981. This maneuver allowed the spacecraft to achieve a speed of over 35,000 miles per hour, allowing it to reach Uranus and Neptune in the following years. Other notable examples include the Juno spacecraft's use of Jupiter's gravity to enter orbit around the planet and the New Horizons spacecraft's flyby of Pluto, both in 2016.