I explain space guns, problems and solutions with space guns and also projects HARP and Babylon in this longest Explained: video yet. Hope you enjoy, and see you in another 2 months!

I really hope you enjoy and learn something from this video, and leave any constructive criticisms and ideas for future videos below.

Sources:
http://www.astronautix.com/a/abriefhi...
http://www.astronautix.com/b/babylong...
https://ntrs.nasa.gov/archive/nasa/ca...
https://history.nasa.gov/afj/launchwi...
http://www.au.af.mil/au/aupress/digit...
https://www.newscientist.com/article/...
https://fas.org/nuke/guide/iraq/other...
http://www.bbc.com/future/story/20160...
https://upload.wikimedia.org/wikipedi...
https://en.wikipedia.org/wiki/Gforce...
   • PBS Frontline  Gerald Bull Supergun´s  

The image of the V3 weapon was provided to Wikimedia Commons by the German Federal Archive.
Space Photo by Egres73 Own work, CC BYSA 3.0, https://commons.wikimedia.org/w/index...
Pentagon photo by David B. Gleason from Chicago, IL The Pentagon, CC BYSA 2.0, https://commons.wikimedia.org/w/index...
Cannon photo by Johann Jaritz Own work, CC BYSA 3.0 at, https://commons.wikimedia.org/w/index...
Photo of neglected HARP gun by Johnmartindavies Own work, CC BYSA 3.0, https://commons.wikimedia.org/w/index...