Daring gravity assist maneuvers of past space missions

With great science comes great engineering

Gravity assists are a powerful technique which can help both extend the duration of a space mission and reduce its overall cost. This article will have a look at some of the most insane gravity assist techniques used in past space missions. If you’re not familiar with the concept of gravity assists, here is a simple explainer.

Studying the Sun from above

1990 saw the launch of joint NASA-ESA mission called Ulysses to study the poles of the Sun for the first time. To study the solar poles, the spacecraft would have to leave the orbital plane of the Solar System and achieve a high inclination orbit.

Artist’s impression of the Ulysses spacecraft. Source: NASA JPL

The only problem? No rocket in existence was (and is) capable of doing that. The solution lay in the largest planet of the Solar System — mighty Jupiter.

Stealing from a planet’s high momentum had been an efficient and established way to achieve high velocities required to achieve mission targets. The Voyager mission had previously utilized this technique to leave the Solar System.

Much like how a change in velocity can be achieved by doing a gravity assist around a planet, a change in inclination is also possible. In 1992, Ulysses performed a…