March's third, or final quarter moon phase will occur at 5:39 a.m. EDT (0939 GMT), as the moon appears in Earth's sky with its left half illuminated by direct sunlight and its rig ...

"ULA’s Centaur (with minor modifications) is the only existing in-space propulsion stage capable of meeting the SLS upper stage design parameters and performance characteristics, while also meeting ...

Venus and Saturn are due up for a visually striking event known as a planetary conjunction. Here's everything to know about ...