Probe
This drawing shows Titan's surface with Saturn in the background. The Cassini spacecraft flies overhead with its antenna pointed at Huygens as the probe nears the surface.

The Huygens probe was designed to study the clouds, atmosphere and surface of one of Saturn's moons, Titan. Image Credit: NASA

      a spacecraft that has tools to gather information about Earth, the moon, another planet or outer space




Sentences:
NASA has sent probes to all the planets in our solar system.

The Spirit and Opportunity rovers are two probes that were sent to Mars.




More Information:
http://www.nasa.gov/mission_pages/cassini/multimedia/pia06434.html
http://www.nasa.gov/images/content/162610main_satellite_model_white_516.jpg