Mission Accomplished

Darkness still enveloped Florida as the Space Shuttle Columbia returned to earth on Tuesday after eleven days in orbit.

At 4:32 a.m. local time, shuttle commander Scott Altman and Pilot Duane Carey brought the Columbia in for a safe landing at Kennedy Space Center. After touch-down, the seven astronauts on board said they were "exhausted but exhilarated."

Difficult mission in space

The six-man, one-woman Columbia crew had successfully completed an ambitious mission: upgrading the Hubble Space Telescope.

Amid five challenging spacewalks, the crew equipped Hubble with a new power unit, new solar wings and a new camera.

The digital camera is the size of a phone-booth and is designed to peer to the ends of the universe. According to NASA, it's the most powerful planetary camera ever launched into orbit.

NASA officials said the five spacewalks of this mission were the most challenging and

risky in the 21-year history of the U.S. shuttle program.

Faithful Mr. Hubble

The Hubble space telescope has been in orbit since 1990 and has provided astronomers with a wealth of information. It has forced scientists to rewrite many of their textbooks based on some of its startling observations.

With the help of data collected by the Hubble telescope, astronomers could prove that stars and galaxies formed much sooner after the Big Bang than they originally thought. Hubble has also supplied scientists with proof that super-massive black holes exist in space.

"Hubble has really opened our eyes to what the universe is made of, its structure, and has helped us learn how little we know about the universe," astronaut John Grunsfeld told the press in an interview before landing. Grunsfeld was the only astronomer aboard the Columbia on this mission.

He added that Hubble had "helped us explore the beauty of the universe in a way that we've never been able to before."

During the mission, Grunsfeld grew so fond of the space telescope that he sometimes affectionately addressed it as "Mr. Hubble".

Columbia's most recent trip into space was the fourth shuttle mission dedicated to servicing Hubble. The space telescope was launched in 1990 on a 20-year mission. A final service mission is planned for 2004 before Hubble's mission in space ends in 2010. What happens then is still out in the open.

There are tentative plans to return the telescope to earth aboard a space shuttle. It may then find its final resting place in the Smithsonian Air and Space Museum in Washington D.C.