How does gravitational assist work?

A gravity assist around a planet changes a spacecraft’s velocity (relative to the Sun) by entering and leaving the gravitational sphere of influence of a planet. To increase speed, the spacecraft approaches the planet from the direction of the planet’s orbital velocity, and departs in the opposite direction.

What is gravity assist and how does it help us to explore space?

The first question is easy—a gravity assist (also called a gravity slingshot) is a space maneuver in which a spacecraft gets a speed boost by moving past a planet. You could also use the gravity assist to slow down or even to change directions. However, in this case let’s just consider boosting the speed.

How do Rockets maintain trajectory?

In the planet’s orbit, the gravitational tug of the planet is high enough to keep the rocket from drifting off into outer space, and low enough so the rocket doesn’t have to burn huge amounts of fuel to keep itself from plummeting back to Earth.

Can you turn a spaceship around?

There is no reason a spacecraft “cannot” do this, but the reason it is entirely impractical is because of the propellant required to change the spacecraft trajectory.

What is the trajectory of a rocket?

The vertical trajectory of a rocket is described by the altitude, velocity, and total mass, h(t), V (t), m(t), which are functions of time. These are called state variables of the rocket. The trajectories are governed by Ordinary Differential Equations (ODEs) which give the time rate of change of each state variable.

Why does rocket trajectory curve?

The explanation is that as they fly, they cover distance both horizontally and vertically – but only the latter is affected by the force of gravity, which bends the path of the projectile into a parabola. For long-range rockets, things are more complex. For example, air resistance must be taken into account.

What was unique about the gravity assist that Voyager used?

Voyager 2 famously used gravity assists to visit Jupiter, Saturn, Uranus and Neptune in the late 1970s and 1980s. Furthermore, the extra speed gained by gravity assists dramatically reduces the duration of a mission to the outer planets. Gravity assists seem a bit mysterious, like one is getting something for nothing.