During a speech to members of the U.S. Marine Corps and other service members at an air base in San Diego this week, President Trump said he’s considering a so-called “space force” similar to the Army, Air Force and Navy. Time magazine editor-at-large Jeffrey Kluger joins “CBS This Morning: Saturday” to discuss a similar intiative under President Ronald Reagan and why it’s unlikely that the U.S. will reach Mars any time soon.