After 30 years of exploration and space dominance, the United States space shuttle program has ended. With the final ‘wheels stopped’ of Atlantis on July 21, 2011, America saw the end of an era.

The space shuttle program was world changing, with 135 trips, and 180 satellites and space probes deployed. The shuttles were also key in the building of the International Space Station.

President George W. Bush decided it was time to move on, announcing that America would halt the space shuttle program in 2011. In its place, he expected another trip to the moon. After taking office, President Barak Obama stated that instead, he would encourage NASA to send a manned flight to an asteroid and, later, a trip to Mars.

For now, NASA officials look at pride at the letter-perfect landing of the final voyage of Atlantis. They plan to place a plaque to mark the spot where the last shuttle ended its final fun.

While the program was exciting and fueled the imaginations of Americans for three decades, it was not without tragedy.

In 1986, the Challenger exploded shortly after lift-off. In front of a horrified crowd, seven astronauts lost their lives. A program meant to bring space travel into the classroom put teacher Christa McAuliffe aboard the Challenger. She perished along with the rest of the astronauts, but their dreams live on. 42 learning centers teach students in three countries about space, space travel and the distance imagination and desire can take you.

In 2003, the nightmare of space tragedy came again when the Columbia burned up on re-entry. A crew of seven was lost, and people wondered if the program could survive.

The program continued for another eight years, until it was retired in the summer of 2011. The International Space Station, still operational, will now be serviced by the Russian space program. American astronauts will ‘hitch a ride’, to the tune of $63 million.

Because the US and Russia both developed space programs at about the same time and battled to see who would be the first to launch, CBS News Space Analyst Bill Harwood observed it is “quite an ironic turn of events, 50 years after the start of the space race.”

What do the astronauts think?

“It is in the DNA of our great country to reach for the stars and explore,” said astronaut Mark Kelley. “We must not stop.”