After a 10-year trip, a European spacecraft has, for the first time, entered an orbit around a comet. The European Space Agency's Rosetta spacecraft began an orbit 100 kilometers above the surface of the comet early Wednesday.

Comets are made of ice and rock. They are periodic visitors to the area immediately around the sun. The Rosetta spacecraft is circling the Comet 67P/Churymov-Gerasimenko.

Currently, Comet 67P is more than 400 million kilometers from Earth. But it is racing closer to the sun. Rosetta will be the first spacecraft to travel with a comet as it moves through the inner solar system.

The European Space Agency has spent $1.7 billion on the project. The American space agency, NASA, provided important support -- three instruments and electronics for the orbiter. NASA also is helping with communications and guidance for the spacecraft.

The goal is for Rosetta to orbit the comet for the next year and observe it as it heads towards the sun. The most important part of the mission is expected to come in November when the spacecraft will send a mechanical probe to land on the surface of Comet 67P. It will be the first soft landing on the surface of a comet.

Scientists hope Rosetta will provide more information about comets. Many scientists believe these objects hold icy remains from the creation of the solar system.

Scientists Hope to Unlock the Secrets of the Young Solar System

The spacecraft is named for a stone that helped investigators understand the meaning of the hieroglyphic language of the ancient Egyptians. Rosetta scientists hope that the spacecraft will unlock the secrets of the beginning of the solar system or even the beginnings of life itself.

Some scientists believe comets contain the materials that helped life start on Earth. The icy bodies are believed to have brought water and other substances to the planet as they struck earth's surface.

Rosetta has traveled over 6 billion kilometers since its launch from earth in March 2004. It made a series of flybys of Mars and Earth to gain speed and position itself into the same orbital path as Comet 67P.

Rosetta's systems were partly shut off for two years to save power. Engineers fully restarted the spacecraft in January as it moved closer to the comet.

I'm Mario Ritter.