Destinations: It's hard to think of ice in the heat of July, unless it is in the form of cubes in a tall glass of iced tea.

But ice, the frozen form of a liquid or gas, exists throughout the solar system, starting with Mercury, the planet closest to the sun, all the way to the vast and diffuse Oort cloud shell of comets. Some planets and moons are composed partly or entirely of ice-some are composed of water ice, while others contain different chemical forms of ice like methane, sulfur dioxide, and hydrogen peroxide. Ice can exist as thick polar caps hundreds of kilometers thick, or crystals in planetary atmospheres. For example, Pluto is 80% ice; Jupiter's moons Ganymede and Callisto and Saturn's moon Titan contain 40% ice. Thick sheets of ice cover the surface of Europa, as well. Ice is also present in many other moons, in planetary ring systems and in comets.

This month we will explore some of the many different forms of ice in nearby planets and moons and toward the far reaches of the solar system.

Missions: The Space Shuttle Discovery is set for launch in July and will evaluate new shuttle safety improvements, and carry supplies and a third crew member to the International Space Station during the 12-day mission.

On July 4, 2005, NASA's Deep Impact mission made history by scoring a direct hit on comet 9P/Tempel 1. This is the first time ice has been detected on the nucleus, or solid body, of a comet.

On July 20th, 1976, the Viking 1 landed on the surface of Mars and gathered images, collected and analyzed samples of the Martian soil, and monitored the temperature, wind direction, and wind speed of the planet.

Features: Ice is almost everwhere we look in our solar system. Take a few minutes to read stories about Mars ice, Titan ice , Europa's surface and ice and Earth Antarctic ice . Many missions have also study ices including the Stardust comet mission , New Horizons and ICESat.

Fast Lesson Finder: K-12 Activities: Search our fast lesson finder to find classroom lessons related to icy worlds. One set of student activities studies comets, which are mostly ice.

People: Meet Deborah Bass: Polar ice expert Deborah Bass knows all about ice in the solar system, especially on Mars.