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• 1 2021-04-16T04:01:08+00:00 SLAMS: The Flying Crowbar 31 The flying crowbar plain 2021-05-21T01:43:17+00:00
  The device itself was called the Supersonic Low Altitude Missile. Despite being the size of a bomber, it was to to be unmanned, without a crew or pilot. The device would have carried an apocalyptic 16 nuclear warheads when fully armed. It would be powered by a nuclear fission reactor that generated up to 600 megawatts of power. This thermal energy (as well as radioactive fission products) was jammed into the combustion chambers of ramjets. The end result was the schematics of a vehicle dubbed "The Flying Crowbar" by project head Ted Merkle.
  
  
  
  
  This allowed a truly wild capability: supersonic speed, barely a hundred meters off the ground to avoid radar and air defenses. The system would be guided by an onboard inertial guidance system, followed by a newly designed system eventually called TERCOM, which is still used in cruise missiles today. Because it was nuclear powered, it could operate indefinitely, able to loiter and fly in circles until called in for a strike. This raised two distinct and very different possibilities: the weapon could be ordered on standby, flying in circles over the ocean at high altitude, with the possibility of being recalled by radio, a feature which ICBMs lack. The other, darker possibility was that the weapon could fly over enemy population centers at low altitude, using it's lethal sonic boom and radioactive exhaust to inflict death and destruction for a prolonged period.
  
  
  
  There were massive downsides however. The exhaust of the vehicle could be likened to a small, mobile Chernobyl disaster. It was so destructive that it was theorized that the weapon could cause damage just by circling around a target before even attacking with it's offensive weapons. Not only would the area behind the exhaust be irradiated, but in the vehicle's final descent phase, it would be burnt and blasted with sonic booms as the SLAMS traversed possibly as low as 80 feet in the air, while flying at Mach 3. Individuals would die from overpressure, and buildings would be devastated. The vehicle would fly to a target, descend to avoid air defenses and radar, and drop up to 16 nuclear warheads on various targets, before finally nosediving and detonating a final warhead. Such a devastating weapon, after being researched since 1956, was finally considered "too Provocative" by the Department of Defense and State Department in July 1964.
  
• 1 2021-04-16T04:08:16+00:00 TERCOM: How a Missile Navigates Before GPS 16 plain 2021-05-21T01:44:51+00:00
  The researchers working on Project Pluto had a problem: the device was too radioactive for a human to safely ride in it without immense shielding. The vehicle also needed to be light in order to fly effectively and achieve it's mission. Therefore, the decision was made to have the device operate without a pilot: it would be unmanned.
  
  Unmanned systems are growing increasingly common in  the modern day. To navigate to a given position, many modern unmanned systems rely on GPS satellites, the same systems that allow modern smartphones to provide location services. But this wasn't an option for the team at Project Pluto. GPS wouldn't be invented for decades. But nonetheless, they needed a system that could reliably navigate at low altitude, in varied weather conditions, without flying into the side of a mountain and detonating in a nuclear fireball. And all of this needed to be done with personal computers still decades away as well.
  
  
  
  This was accomplished by two systems which would operate at different times throughout the mission profile. During the first section of the mission, represented in the image above by the high flying trajectory on the left, an inertial guidance system operated while the vehicle was at it's cruise speed, 35,000 feet in the air.
  
  After the vehicle dived down towards the ground to evade radar, it would use what would eventually be called TERCOM, or Terrain Contour Matching. The system compared radar images of features on the ground to a prerecorded list of possible landmarks in it's memory, based on it's flight path. it would compare it's radar returns with this internal memory, and guide itself to targets. TERCOM is still used in the US Tomahawk cruise missile to this day.
  
  It is succinctly, if hilariously, described in this video, which utilizes audio from an official training film: