For 14 years, the Galileo spacecraft explored the most massive planet in our solar system – a planet so big that 1,300 Earths would fit inside of it. In addition to studying Jupiter, Galileo studied the planet’s largest moons and was the first to visit an asteroid.
Galileo. Image Credit: NASA
Earlier this week and 13 years ago, Galileo’s mission ended. On September 21, 2003, the spacecraft was purposefully smashed into the gas giant’s atmosphere.
Why?
The mission found evidence of salt water below the surface on one of Jupiter’s moons, Europa. Destroying Galileo would avoid disturbing an ocean that could exist underneath the moon’s icy crust.
Galileo studied the atmosphere of Jupiter and learned that it had thunderstorms much larger than those on Earth. Faint, narrow rings around the planet are caused by meteoroids that impact the closest moons, a discovery also made by Galileo.
What has the mission taught us about Jupiter’s largest moons?
We have learned that some volcanoes on the moon Io are hotter than those on Earth. Images taken by Galileo of Europa show the moon’s surface as being relatively young and having giant ice chunks the size of cities with warmer material coming up from underneath the surface. Europa also has a thin atmosphere of oxygen. We know from Galileo that the Largest moon in the solar system, Ganymede, has a magnetic field of its own. The moon Callisto could have an ocean under its surface.
The Galileo spacecraft was the first to fly by an asteroid, 951 Gaspra, and also the first to find an asteroid moon orbiting around another asteroid, 243 Ida.
NASA’s Galileo mission launched in 1989 from Kennedy Space Center inside the payload bay of Space Shuttle Atlantis. The spacecraft was named for Galileo Galilei who was the first to observe the sky with a telescope back in 1610.
Galileo’s deployment from the space shuttle Atlantis. Image Credit: NASA
The Jet Propulsion Laboratory (JPL) in Pasadena, California, designed and built Galileo. Although Galileo’s mission ended in 2003, we are certainly not done exploring Jupiter. Today, NASA’s Juno spacecraft continues to study the king of planets.
Learn more about Galileo at NASA.gov.