The Ill-Fated Canadian Behind Saddam Hussein's Space Gun

In the history of space exploration, the majority of manned and unmanned missions have been conducted with multi-stage rockets. The cost of these spacecraft has gone down substantially over time, to the point that from the 2010s onward American astronauts have hitched their rides aboard Russian rockets (via NBC). Efforts to further reduce spaceflight cost, such as reusable spaceplanes like the Space Shuttle, have often been plagued by counter-intuitively higher costs and higher-than-acceptable failure rates. One idea that showed some promise, however, was the space gun. 

This concept involves a massive cannon firing a capsule full of space-bound cargo, such as food for astronauts or satellites. The projectile would ideally either reach the thermosphere by itself or at least high enough that an integrated rocket could propel it the last few miles into space (via Today I found Out). Such a system could, in theory, eliminate the need for rockets to transport non-living material. Project HARP (High Altitude Research Project) was the Cold War program through which the United States and Canadian governments tested its viability for missiles (via Atlas Obscura). The project was headed by Canadian engineer and artillery expert Gerald Bull (above), whose desire to see the concept realized led him on a tragic path.