Elon Musk Shows Childlike Joy (and Dread) in Rocket-Landing Video

Billionaire entrepreneur Elon Musk typically displays such an incredibly calm demeanor that it's hard to imagine him getting excited about anything. But in a newly released video, Musk makes an uncharacteristic display of emotion, ranging from dread to unbridled joy as he watches a Falcon 9 reusable rocket booster make its historic first landing at Cape Canaveral, Florida, on Dec. 21, 2015. The video, released by National Geographic as part of its "Mars" miniseries coverage, shows