Video: Orion launch replays

Officials hailed an action-packed three-minute test flight Tuesday over Cape Canaveral that exercised the Orion spacecraft’s launch abort rocket, a key safety system on the capsule NASA is developing to carry astronauts back to the moon.

The four RS-25 engines at the bottom of NASA’s first Space Launch System core stage shut down about a minute into a ground test-firing Saturday that was supposed to last more than eight minutes.

The year ended with a deluge of big news, reminding us of the risks of spaceflight and the thin margins between success and failure on the final frontier. 2014 was also a year of breakthroughs in the exploration of the solar system and the future of human spaceflight.