Loss of the motor robs the spacecraft of the ability to steer or communicate, and reduces overall mission success
NASA’s Cassini spacecraft has crashed into Saturn on Monday. Photograph: NASA/JPL-Caltech/Space Science Institute
The NASA spacecraft Cassini has crashed into Saturn. The spacecraft, which has spent 15 years in orbit around the solar system’s biggest planet, has smashed into Saturn’s atmosphere on Monday after the disintegration of its radiation shield disintegrated an engine motor that was used to steer the spacecraft.
The accident, which will not damage the instruments of the spacecraft, may also have fatally scuppered the hope of finding signs of life on Saturn’s surface, a project of recent priority in the space agency’s exploration of the solar system.
Scientists had hoped Cassini would be able to use that motor to steer the craft to hit Saturn’s atmosphere, reaching a maximum speed of nearly 85,000mph before the crew had managed to separate the motors.
While there was one remaining battery in the motor when Cassini disappeared off radar in Saturn’s atmosphere, it was rapidly depleted in the hours before the crash and the final explosion. The vehicle had been in danger of running out of coolant which could have caused it to overheated and lose control over its trajectory.
The scientists hoped Cassini would travel for around one Earth year when it went into the atmosphere. Because Cassini and Saturn were so close, the impact would generate a huge explosion that would illuminate the planet’s atmosphere and wreak havoc on instruments on board the spacecraft.
This is the end of Cassini – which orbits Saturn from a distance of about 45,000km, half the distance between London and Rome, and one-third of the distance between Earth and the sun.
Cassini’s main mission, according to project scientists, was to find out why Jupiter and Saturn’s moons formed and to understand the planet’s atmosphere.
The spacecraft’s twin, dubbed Voyager, discovered the first hints of Saturn’s rings in the 1970s. The larger and more distant spacecraft launched in the early 1980s witnessed Saturn’s rings being formed by the super-fast movement of the planet’s icy moons. Cassini confirmed the rings’ existence by studying the planet’s gravitational field.
Before its last mission mission was given the green light, NASA engineers had to overcome a number of technical problems that included fuel supply, power supply and the requirements for sufficient oxygen to run the plutonium-powered instruments that monitored the spacecraft’s environment.
Though Cassini has mapped Saturn’s cloud tops, left traces of water ice in the planet’s atmosphere and watched tiny particles drift into the planet’s rings, it cannot capture images of the planet’s surface.
Cassini will be examined by a team from the space agency’s Jet Propulsion Laboratory for the past 20 years before the spacecraft is deliberately smashed into Saturn on 1 September 2016.