In its 26-year history, the space shuttle program has seen exhilarating highs and devastating lows. The fleet has taken astronauts on dozens of successful missions, resulting in immeasurable scientific gains. But this success has had a serious cost. In 1986, the Challenger exploded during launch. In 2003, the Columbia broke up during re-entry over Texas. Since the Columbia accident, the shuttles have been grounded pending redesigns to improve their safety. The 2005 shuttle Discovery was supposed to initiate the return to flight, but a large piece of insulating foam broke free from its external fuel tank, leaving scientists to solve the mystery and the program grounded once more until July 2006, when the Discovery and Atlantis both carried out successful missions.

In this article, we examine the monumental technology behind America's shuttle program, the mission it was designed to carry out, and the extraordinary efforts that NASA has made to return the shuttle to flight.

Photo courtesy NASA Liftoff of the space shuttle. See more space shuttle pictures.

First, let's look at the parts of the space shuttle and a typical mission.

The space shuttle consists of the following major components:

• two solid rocket boosters (SRB) - critical for the launch
• external fuel tank (ET) - carries fuel for the launch
• orbiter - carries astronauts and payload

The space shuttle flight path. Mouse over the boxes to see the stages.

A typical shuttle mission is as follows:

• getting into orbit
  • launch - the shuttle lifts off the launching pad
  • ascent
  • orbital maneuvering burn
• orbit - life in space
• re-entry
• landing

A typical shuttle mission lasts seven to eight days, but can extend to as much as 14 days depending upon the objectives of the mission. Let's look at the stages of a mission one by one.

Learn More on the Discovery ChannelThe Hubble Space Telescope uses a system of cameras and mirrors to detect distant star light. Learn how the Hubble sees in this video from the Discovery Channel.

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