Trump’s pledge to go to Mars without mentioning the moon has caused some head-scratching and even consternation in the media.

Images of the Billionaires’ Row circled the globe, inspiring the same fascination that greeted pictures of five current and former presidents assembled at Jimmy Carter’s funeral earlier in the month.

As companies like SpaceX and Virgin Galactic make waves in space tourism, how long does the rest of the world have to wait ...