Gif animation Cassini-Huygens spacecraft
Artist's impression of Cassini-Huygens

Cassini spacecraft

The Cassini-Huygens spacecraft is one of the largest, heaviest and most complex interplanetary spacecraft ever built. Of all interplanetary spacecraft, only the two Phobos spacecraft sent to Mars by the former Soviet Union were heavier.

Loaded with an array of powerful instruments and cameras, the spacecraft is capable of taking accurate measurements and detailed images in a variety of atmospheric conditions and light spectra.

Two elements comprise the spacecraft: the Cassini orbiter and the Huygens probe. After arrival at Saturn, the spacecraft will then orbit around the Saturnian system for four years; sending data back to Earth that will help us understand this region.

Cassini-Huygens is equipped for 27 diverse science investigations. The Cassini orbiter has 12 instruments and the Huygens probe has six. The instruments often have multiple functions, equipped to thoroughly investigate all the important elements of the Saturnian system.

Cassini was the first planetary spacecraft to use solid-state recorders without moving parts instead of the older tape recorder.

Cassini-Huygens passing through the gap in the rings


The Cassini-Huygens spacecraft communicates with Earth through its antenna subsystem, consisting of one high-gain antenna and two low-gain antennas.

The primary function of the high-gain antenna is to support communication with Earth, but it is also used for scientific experiments. During the early portion of the long journey to Saturn, the high-gain antenna was positioned toward the Sun, functioning like an umbrella to shield the spacecraft’s instruments from the harmful rays of the Sun.

The spacecraft would communicate through one of its low-gain antennas only in the event of a power failure or other such emergency situation.

Huygens being fitted to Cassini before undergoing tests
Technicians fit Huygens to Cassini before starting tests


The Cassini spacecraft stands more than 6.7 metres high and is more than 4 metres wide. The magnetometer instrument is mounted on an 11-metre boom that extends outward from the spacecraft.

The orbiter alone weighs 2125 kilograms. Total mass of the Huygens probe is 349 kilograms, including payload (49 kilograms) and probe support equipment on the orbiter (30 kilograms).

The launch mass of Cassini-Huygens was 5.82 tonnes, of which 3.1 tonnes were propellant.


Three Radioisotope Thermoelectric Generators (RTGs) provide power for the spacecraft, including the instruments, computers, radio transmitters, attitude thrusters and reaction wheels.

Copyright 2000 - 2018 © European Space Agency. All rights reserved.