On April 15, 2005, NASA launched a spacecraft on a mission to rendezvous with a small communications satellite. The launch went according to plan, but the mission ended abruptly when the spacecraft collided with the satellite. The mission was known as DART, which is short for Demonstration for Autonomous Rendezvous Technology. Its objective was to demonstrate that a fully automated and uncrewed spacecraft could rendezvous with another spacecraft in orbit. But the two spacecraft were not supposed to make contact. When DART approached its target, it ran out of fuel and inadvertently bumped into it. Investigators determined that DART’s thrusters had been firing excessively because of a problem with its navigation system. It was a soft collision, and neither of the spacecraft were noticeably damaged.