A tragic accident that set back manned exploration two years. Thankfully, space exploration has finally been giving the re-energizing effort that it so deseprately needed. The shuttle will relaunch in May to continue construction on the International Space Station. Meanwhile, while numerous unmanned probes (i.e. Jupiter Icy Moon Orbiter, Mars Reconnasiance Oribter) are being developed, the manned 'CEV' or Crew Exploration Vehicle is being developed as the next-generation replacement for the shuttle. The end goal--men back on the moon and eventually Mars. Space has never seen so within reach for mankind.

In terms of importance, the explosion of the Space Shuttle Columbia was largely inconsequential. Despite the subsequent probe into the accident, nothing of great consequence resulted from the tragedy. No clear changes have been made at NASA to prevent another such accident. Overall, a tragic event, but in the context of other events in 2003, this is not too important.