Hubble Eye of infinity

The Hubble telescope, with a new camera installed in March 2002, reveals the cosmos more clearly than ever before, sending back exquisite views of a complex universe.
Hubble was built to be tuned up in orbit. But it wasn't designed for the major overhaul NASA astronauts undertook during its fourth servicing mission, 3B, in March 2002. They delved into the telescope's guts during long space walks, like the one shown here illuminated by a sunlit crescent of Earth, and replaced parts that the original designers never thought they'd need to.
Installation of a new power-control unit forced an unprecedented and nerve-wracking shutdown of the entire satellite—a move comparable to a surgeon stopping a patient's heart during surgery, says Anne Kinney, NASA's director of astronomy and physics. Astronaut John Grunsfeld raced to finish the task before the temperature of the switched-off telescope dropped far enough to damage it. Would it power back up? "When you run a computer for 12 years, you don't know what kind of ghosts you have in the system," Kinney says. When all systems reactivated as planned, the astronauts, as well as astronomers and mission controllers on the ground, breathed a collective sigh of relief. The rest of the mission went like clockwork, including installation of a new cooling system for Hubble's near-infrared camera—NICMOS—useful for surveying dusty and cold areas of space, and installation of new solar panels and other science equipment.

It was the most challenging service mission ever attempted in space, and its success elated astronomers. Chief among the wonders was the long-awaited ACS, or Advanced Camera for Surveys. It essentially made Hubble into a new telescope. "ACS has roughly ten times the discovery power of the previous camera," says Mario Livio, astronomer at the Space Telescope Science Institute in Baltimore. Translation: Hubble can now see twice as much with five times more light sensitivity.

Tragically, this mission would be the last successful voyage for space shuttle Columbia;. The disaster in February 2003 grounded Discovery, Atlantis, and Endeavour, the three remaining shuttles, and will delay plans to bring Hubble a spectrograph and a new wide-field camera with ultraviolet and infrared capability.

Asteroid Belt

An asteroid is a bit of rock. It can be thought of as what was "left over" after the Sun and all the planets were formed. Most of the asteroids in our solar system can be found orbiting the Sun between the orbits of Mars and Jupiter. This area is sometimes called the "asteroid belt". Think about it this way: the asteroid belt is a big highway in a circle around the Sun. Think about the asteroids as cars on the highway. Sometimes, the asteroid cars run into one another. When this happens, the asteroids may break up into smaller asteroids. Scientists think that most asteroids are the result of collisions between larger rocky space bodies.

Asteroids can be a few feet to several hundred miles wide. The belt probably contains at least 40,000 asteroids that are more than 0.5 miles across.

If an asteroid is captured by the gravitational pull of a planet, the asteroid can be pulled out of the belt and go into orbit as a moon around the planet that pulled on it.

Solar System Live

Welcome to Solar System Live, the interactive Orrery of the Web. You can view the entire Solar System, or just the inner planets (through the orbit of Mars). Controls allow you to set time and date, viewpoint, observing location, orbital elements to track an asteroid or comet, and a variety of other parameters. Click on the title of any control to display a help page explaining it, or go directly to the help table of contents. You can compose a request with custom settings and save the results in your browser's hotlist or bookmark table, allowing direct access to Solar System Live with all the controls preset to your own preferences.