Galileo project

A robot went to space to study Jupiter.

It was named Galileo. It had a part that could fly into the clouds.

This part measured the air of the big planet. The robot also looked at many moons. It found that some moons might have oceans under the ice.

It even saw a comet hit the planet. The robot worked for a long time in space. It helped us learn so much about our world.

Galileo was a robotic space program. It was built to study Jupiter.

The spacecraft had two main parts. One part was an orbiter. It circled the planet. The other part was a probe. This probe went into the clouds.

It was the first probe to measure Jupiter's air.

Galileo found many new things. It saw a comet hit Jupiter in 1994. It also found a small moon near an asteroid.

The spacecraft looked closely at Jupiter's moons. It found that Europa might have a liquid ocean under its ice.

It also saw signs of water under Ganymede and Callisto.

Jupiter has a big magnetic field. This is a force that pulls on things. Galileo helped map this field. It also found that Jupiter has a faint ring system. These rings are made of dust. The dust comes from small moons hitting each other. The mission lasted for many years. In 2003, the orbiter was sent into Jupiter. This kept the moons safe from Earth bacteria.

The Galileo project was a robotic space program used to study Jupiter.

Jupiter is the largest planet in our solar system. It has more than twice the mass of all other planets combined. The spacecraft was named after the Italian astronomer Galileo Galilei. He was the first person to see Jupiter through a telescope in 1610.

The spacecraft had two main parts: an orbiter and an atmospheric entry probe. The orbiter circled the planet to collect data. The probe was sent to dive directly into the clouds to measure the air.

To reach the giant planet, the spacecraft followed a long path.

It was delivered into Earth orbit on October 18, 1989. To gain enough speed, it used gravity assist flybys. This means it flew close to Venus and Earth to use their gravity to move faster.

It finally arrived at Jupiter on December 7, 1995. This made it the very first spacecraft to orbit Jupiter. Once it was in orbit, it could act as a relay for the probe. The probe would send information back to the orbiter, which then sent it to Earth.

Many people worked hard to make this mission happen.

NASA's Jet Propulsion Laboratory was the lead center for the project. John R. Casani was the first project manager. The project faced many hard jobs during its start. For example, the technology to build a heat shield for the probe did not exist yet. Scientists also worried about radiation from Jupiter. They needed to understand how radiation affects spacecraft parts. They learned more about this from earlier missions like Pioneer 10 and Pioneer 11.

Galileo discovered many amazing things during its years in space.

It performed the first flyby of an asteroid named 951 Gaspra. It also found a tiny moon called Dactyl near the asteroid 243 Ida.

In 1994, it watched Comet Shoemaker–Levy 9 crash into Jupiter.

The spacecraft studied the moons very closely. It found that Europa might have a liquid ocean under its icy surface.

There were also signs of saltwater layers under Ganymede and Callisto.

It even found that Jupiter has a faint ring system made of dust.

The mission lasted much longer than anyone expected.

The primary mission ended on December 7, 1997. However, it started an extended mission called the Galileo Europa Mission. This second part lasted until December 31, 1999. The spacecraft had absorbed three times more radiation than it was built to handle. By the end, many instruments were not working perfectly. On September 20, 2003, the mission finally ended. NASA sent the orbiter into Jupiter's atmosphere to stop it from spreading Earth bacteria to the moons.

The Galileo project was an ambitious American robotic space program. Its primary goal was to study Jupiter and its many moons. It also examined several other bodies within our Solar System.

The mission was named after Galileo Galilei. He was the Italian astronomer who first observed Jupiter through a telescope in 1610. The spacecraft was composed of two distinct parts. One part was an orbiter designed to circle the planet. The other part was an atmospheric entry probe. This probe was designed to dive directly into Jupiter's clouds.

To reach the giant planet, the spacecraft followed a complex path. It was delivered into Earth orbit on October 18, 1989, by the STS-34 mission. To gain enough speed, it used gravity assist flybys. The spacecraft flew past Venus and Earth to use their gravity for momentum.

This journey allowed it to arrive at Jupiter on December 7, 1995. Upon arrival, it became the first spacecraft to ever orbit Jupiter. Once in orbit, the orbiter acted as a relay station. It received data sent from the atmospheric entry probe. The orbiter then transmitted that information back to scientists on Earth.

Developing the mission required overcoming many technical hurdles. NASA's Jet Propulsion Laboratory (JPL) served as the lead center. In the late 1970s, engineers realized they needed better technology for the probe. Specifically, they needed a heat shield that could survive Jupiter's atmosphere. Testing facilities for such a shield were not available until 1980. Scientists also had to account for intense radiation. Earlier missions like Pioneer 10 and Pioneer 11 provided data on these effects.

The orbiter used a Mariner-style attitude control system. This system used gyroscopes and nitrogen jet thrusters to maintain its position. This allowed the spacecraft to take very high-resolution images of its surroundings.

Planning the launch was also a difficult process. NASA originally intended to use the Space Shuttle to launch the project. They planned to use an Interim Upper Stage (IUS) to push the craft toward Jupiter. However, the orbiter was very heavy. A two-stage IUS was not powerful enough for the mission. NASA considered a three-stage IUS, but the cost was too high. The cost for the three-stage version was $179 million. This was $100 million over the original budget.

Eventually, NASA decided to use a Centaur G Prime upper stage instead. This change ensured the mission could proceed on a reasonable schedule.

Galileo achieved many scientific firsts during its mission. It performed the first asteroid flyby of 951 Gaspra. During this encounter, it also discovered Dactyl, the first known asteroid moon.

In 1994, the spacecraft observed Comet Shoemaker–Levy 9 colliding with Jupiter.

It also mapped the structure of Jupiter's magnetosphere. This is the region of space dominated by the planet's magnetic field. Additionally, Galileo discovered that Jupiter has a faint ring system. This ring is made of dust from impacts on the four small inner moons.

One of the most significant discoveries involved the moons of Jupiter. Galileo studied the composition of the atmosphere and the ammonia clouds.

The spacecraft observed volcanic activity on the moon Io.

It also found evidence of exospheres around Europa, Ganymede, and Callisto. Most importantly, the data supported the theory of a liquid ocean under the icy surface of Europa.

There were also indications of similar saltwater layers under Ganymede and Callisto.

Ganymede was even shown to possess its own magnetic field.

The mission lasted much longer than its original design. The primary mission ended on December 7, 1997. This was followed by the Galileo Europa Mission (GEM). This extended mission ran until December 31, 1999. Later, a second extension called the Galileo Millennium Mission (GMM) was authorized. By the end, the spacecraft had absorbed three times the radiation it was built to withstand.

On September 20, 2003, the mission was finally terminated. NASA sent the orbiter into Jupiter's atmosphere at high speed. This was done to prevent the spacecraft from contaminating the moons with Earth bacteria.