http://www.ipmsstockholm.org/magazin...ff_eng_x15.htm
66671 Information if you're interested.
Amazing craft, all of them. It was possible for these to go into space, they had thrusters built in but for some reason the USA restricted the flights although some pilots were accorded 'astronaut' status if the flew over 50 miles high. Mach 6.0 ...!
I think I still have the news clippings from the times they flew. Along with first satellite launches, first manned launches, Moon landings etc.