system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If NASA knew Columbia was damaged, why could the shuttle not have docked at ISS while another shuttle was prepared and sent to rescue Columbia crew?
gpt
Columbia was in a different orbital inclination than the ISS, orbiting at a 39 degree tilt relative to the equator vs. 51.5 degrees for the ISS. That doesn't sound like a lot, but the Shuttle did not have nearly enough fuel to rendezvous with the ISS, so that wasn't an option.

After the disaster, future Shuttle missions not going to the ISS had a backup Shuttle prepared for a rescue mission while they were in space.