 Hey what's up everybody it's Throwback Thursday and today I wanted to talk about the X-15 the first true space plane for our third installment of space plane history. For this your space pod for May 21st 2015. So in part one of space plane history I talked about the Nazi silver Vogel and in part two I talked about the rocket-powered aircraft that paved the way for the X-15 program. The X-15 was based on a concept study by Walter Dornberger which he made for the NACA the National Advisory Committee for Aeronautics and starting in 1954 after multiple proposals the NACA selected North American aviation to build the airframe and reaction motors to build the rocket engine. Like the Bell X-1 the X-15 was designed to be dropped from a mothership in this case the B-52 stratofortress after which it would fire its rocket engine to achieve high altitudes and speeds which was the purpose for the vehicle to be a hypersonic research aircraft. Since the X-15 was designed to fly at high altitudes and speeds normal flight control systems weren't effective enough to maintain control of the vehicle. Thus it was equipped with reaction control thrusters for maneuverability and it also featured the first stability augmentation system or SAS to help the pilot maintain control of the vehicle. Players of Kerbal's space program should be very familiar with what the SAS system does and speaking of Kerbal in the event of a failure the cockpit did feature an ejection seat although it never was used. The X-15 also had a thick tail fin that gave additional stability although when it came time to land its retractable landing skids and front landing gear did not extend beyond the ventral fin so the pilot would jettison the lower fin just before landing. Early flights of the X-15 used two XLR-11 rocket engines built by reaction motors until the single engine XLR-99 engine was ready. The XLR-99 engine was throttable and was the first man rated controllable rocket engine. Three X-15s were built and flew 199 times between June 8th of 1959 and October 24th of 1968. Of those flights 13 flights would ascend past the 50 mile or 80 kilometer mark that the United States Air Force qualified as suborbital space flights and they awarded astronaut wings to the pilots who flew those flights. Of those 13 flights two of those ascended past the 62 mile or 100 kilometer internationally accepted boundary of space. Twelve pilots flew the X-15 including future astronauts Neil Armstrong of Apollo 11 fame and Joe Engel who would be a commander on the space shuttle Enterprise test flights and the second flight of the space shuttle Columbia. The second X-15 vehicle was rebuilt after a landing accident and featured many upgrades including a sealed a blade of coating as well as a pair of auxiliary fuel tanks attached beneath its fuselage and wings. It was renamed the X-15A-2 and flew for the first time on June 20th of 1964. This upgraded version also reached the program's maximum speed record of 4520 miles per hour on a flight in October of 1967. Although the X-15 program was highly successful in what it was able to achieve and the successful flights that it did have, it did have one fatal failure. On November 15th of 1967 United States Air Force test pilot Major Michael J. Adams was killed during the 191st test flight of the X-15 when his aircraft entered a hypersonic spin when it was descending and at 60,000 feet the airframe broke apart scattering wreckage over a 50 square mile radius. Major Adams was awarded the United States Air Force astronaut wings for his final flight which did reach an altitude of 50 miles and in 1991 his name was added to the astronaut memorial. Just like any experimental aircraft or spacecraft test program, there are lots of risks involved and all of the pilots and crew members that were responsible for the X-15 program knew those risks and there were lots of other experiences where people could have lost their lives during the program but thankfully didn't. In any case, the sacrifices and time spent by the men and women involved with the X-15 program would lead to many advances in spaceflight. Some information was even used on Project Mercury to get the first American astronauts into suborbital and then orbital space. Of course, there was lots of information that was used on follow-on spaceplane programs including the space shuttle and we're going to talk about more of those the next time that we talk about spaceplane history but for now I'm going to leave it at that with some of these really cool essentials about the X-15 program. Thank you very much for watching this video. My name is Michael Clark and if you're so inclined please share this video with your friends so that you too can raise awareness about space and please comment on this video. I would love to hear what you think about the X-15 program and some of these essentials that we discussed. Please subscribe to our channel if you haven't already and also contribute to our Patreon campaigns so that we can continue bringing you space news like this. Again, thank you very much for watching and until the next time I see you guys keep moving onwards and upwards.