Back in the 1950s, when rocketry was extraordinarily difficult, and TV was full of videos of NASA rocket tests failing miserably, Gerald Bull had an alternative idea: Use a giant gun to put a payload in orbit. This led to Project HARP, which got a lot of great research done. By the 1960s, we had figured out (mostly) how to make rockets that work. It was still hard, but now we could generally expect launches to work. And so the plug was pulled on HARP, but Gerald Bull still dreamed of using a giant gun to put a satellite in orbit. Eventually, in the 1980s, he found someone with money willing to back his dream once more. That man was Saddam Hussein.
Project Babylon came in two phases. Stage one was “Baby Babylon”, a proof of concept model with a 350mm bore and a barrel length of 46 meters. This was initially used for horizontal testing, and was then erected on the side of a mountain. The full size “Big Babylon” would have been the biggest gun ever, with a one-meter bore and a barrel length of 156 meters. The original design was intended to be suspended from a steel framework by a system of cables.
Testing of the Baby Babylon cannon showed issues in dealing with seals between the barrel sections. While these were being fixed, Gerald Bull was assassinated outside of his Belgian apartment on March 22, 1990, which crippled the project. It would not be resumed after the First Gulf War.
Bull’s assassination was almost certainly not due to his work on Project Babylon. The superguns were massive, fixed targets. Easy to spot with aerial or satellite reconnaissance, easy to destroy. But Bull was also working on improving the range of Saddam’s Scud missiles. Those are much more effective than a giant gun. This was the project that most likely angered Saddam’s enemies enough to get an assassination. The most likely candidates are Israel or Iran, both of whom have intelligence agencies with lots of experience in liquidating potential problems.
Project Babylon itself is also extremely problematic. It’s a lousy weapon, as we’ve mentioned before. But I’m also extremely skeptical of their utility as a launch system. Even with a 156 meter barrel, the acceleration is going to be absolutely brutal. This is going to seriously restrict the payloads you can launch. A rocket is going to be far gentler on the payload, and much less likely to wreck a satellite. Plus, rockets can accept oversize shrouds to handle larger payloads, or be clustered to lift more weight. You’re pretty stuck with the weight capacity and payload diameter restriction here.
Verdict: Funding Request Denied by the Borgundy Ordnance Board