Time-lapse: Falcon 9 lifted vertical on pad 39A (members only)

Trouble with a piece of ground equipment used for testing of the 10 Iridium communications satellites aboard the next Falcon 9 rocket launch has forced a 24-hour delay in the mission to Friday, officials said Tuesday.

Gearing up for a predawn blastoff July 31, launch crews have positioned a Delta 4-Heavy rocket in the starting blocks on a seaside launch complex at Cape Canaveral as engineers inside a tightly-controlled clean room a few miles away put the final touches on a NASA probe that will travel closer to the sun than any mission before.

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.