 The X-15 rocket plane was a phenomenal research vehicle. It was designed to probe issues of atmosphere keating when returning from near orbital altitudes and also probe the realms of hypersonic manned flight. But on November 15th of 1967, Mike Adams became its first and only victim. And that's the sad story we're talking about today on Vintage Space. The flight that killed Mike Adams was his seventh flight in the X-15 and his fourth high altitude research flight. The day began like any other with Adams, secured in the X-15 cockpit, nestled under the wing of a B-52 launch plane. The B-52 took off, and then at 10.30 that morning, released Adams in the X-15 over a Delamar dry lake bed. An altitude flight, as soon as Adams separated from the B-52, he lit his rocket engine and began a steep climb to his planned altitude of 250,000 feet. But as he passed through 83,000 feet, an electrical disturbance rooted in the nose-mounted traversing probe experiment caused a transient motion in the reaction control system motors. The motors that controlled the small hydrogen peroxide jets that controlled the plane when it flew above the atmosphere. This deactivated the normal reaction controls and also affected the inertial system computer and the boost guidance system, leading to errors displayed in the cockpit. Following his flight plan, Adams shut down his engine but momentum carried him ever higher. As he passed over his peak altitude, which was actually 266,000 feet, and he was traveling at almost 4,600 miles per hour, his heading began to drift. At the peak of his ballistic flight, his heading had drifted by 90 degrees. As he began to come down and pass through 230,000 feet, his heading had drifted by 180 degrees. And then it began to spin. Adams lost about 100,000 feet in just 15 seconds, and as the atmosphere thickened, the spin gradually evened out. But then the rear stabilizer began oscillating back and forth, forcing the aircraft to oscillate in pitch and roll. The movement started small but got worse as the X-15 fell through an increasingly dense atmosphere at nearly 3,000 feet per second. Coming through 80,000 feet, the oscillations had become so strong that the X-15's fuselage actually buckled from the sideways forces. Telemetry said that inside the cockpit, Adams was pulling about 13 Gs at this point, and still traveling about four times the speed of sound. Less than five minutes after he'd released from the B-52, one of the chase planes reported seeing dust in the desert, an unmistakable sign of a crash. The largest piece of the wreckage was the forward fuselage, and it was found flattened with its nose gear ripped out, landed upside down. At 11.02 in the morning, Adams's remains were found in the cockpit. The accident investigation pointed to the electrical disturbance and the aerodynamic issues as the cause of the crash, but also mentioned Vertigo. Adams wasn't the first X-15 pilot to experience Vertigo in flight, in fact, it was something he'd experienced on previous flights, and it was the only way to explain why he hadn't noticed that his heading was drifting. Mike Adams was posthumously awarded astronaut wings for the flight. His peak altitude of 266,000 feet is about 50.38 miles, which is just over the 50-mile threshold where air gives way to space. In 1991, Adams's name was added to the astronaut memorial at the Kennedy Space Center in Florida. In June of 2004, a memorial to Adams was dedicated by Eagle Scout John Badilski at the crash site. It's minimal, but amazing. I had a chance to visit the site last weekend with a group of similarly space-loving friends. The memorial includes a monument that weighs nearly two tons, featuring an engraved plaque with Adams's picture on it and the story of the last flight, and it's actually made of Incanel X, the same material used to construct the X-15. The minimalism of the memorial is actually quite beautiful and really quite moving that it's not bombarded with anything. It's silent out there, and it's wonderful to reflect that you're standing where a terrible piece of history was made, and it's also just wonderful to reflect on Mike Adams as a pilot who gave his life for research. For more on Mike Adams' final flight and my trip out to the memorial, check out the latest post on vintage space over at Popular Science. And for more spaceflight content and a lot of space history content every day of the week, be sure to follow me on Twitter as AST Vintage Space. And as always, with episodes going up every Tuesday and Friday, don't forget to subscribe right here so you never miss an episode.