Using Cannons To Launch Spacecraft
Launching spacecraft using a cannon seems to be an idea that dates back several centuries. Jules Verne proposed using a giant cannon to launch a spacecraft to the moon in his novel "From The Earth To The Moon". But this idea was not always in the realm of science fiction. Many thought that this method of launch might be possible and indeed, even today, it has its supporters. One method for cheap launches that was proposed, was for a rail gun to be set up on the Moon. Since the Moon's gravity is much lower than the Earth's, it doesn't take as much energy to get out of the Moon's gravitational field. While a rail gun is not exactly a cannon, it does shoot things. It works on electro magnetism and is really a modern catapult. The use of a rail gun on the moon would lower the expense of sending out interplanetary missions from that body. This is not so far fetched since the newest aircraft carriers will soon use a type of rail gun to launch planes. These planes were formerly launched using a steam catapult. Some have even proposed building a rail gun powerful enough to launch an object from the Earth. This would be quite a feat if it could be accomplished. A rocket uses much of its fuel just to get into orbit, so this would have a great advantage in fuel savings.
Drawing Source: US Navy
Miniature spacecraft about the size of coffee cans could be launched by electromagnetic launchers to conduct dozens of different space exploration missions, according to an engineer at NASA's Jet Propulsion Laboratory in Pasadena, Calif. Ross M. Jones of JPL's spacecraft systems engineering section said that Earth-orbiting electromagnetic launchers, or railguns, being developed for the U.S. Strategic Defense Initiative Office (SDIO), would be useful in launching very small, low-cost scientific probes to various destinations in the solar system. Jones discussed the proposal in his paper presented at the American Institute of Aeronautics and Astronautics' Aerospace Sciences Conference held in Reno, Nev. Electromagnetic launchers are being developed by the U.S. military for use both on the ground and in space. Instead of using explosive power to propel projectiles, electromagnetic guns and launchers generate brief but powerful electrical pulses that in turn produce strong electromagnetic forces that accelerate projectiles to extremely high velocities.
Cannon launches are still being worked on. An experiment took place putting 19 tiny electric thrusters on a device the size of penny. The idea is to shoot these small devices out of a cannon and when then begin to slow down, their own thrusters would take over. By that time it wouldn't require much fuel for them to break Earth's orbit. It is estimated that this method could be used on micro satellites that weigh about 2.2 pounds and are about four inches in diameter. Ah Mr. Verne we are getting there. Satellites are getting smaller and lighter every day anyway, so it shouldn't be a hard job getting them small enough for the cannon. By the way, the reason Jules Verne chose a cannon to launch his space vehicle was that at the time, no one believed that rockets were powerful enough to launch a space vehicle.
H.A.R.P. was a Canadian program carried out by the Canadian and US Governments. It stands for High Altitude Research Program. This program was dedicated to substituting cannons for rockets for launch vehicles. The idea for this project came from work that was being conducted in the US and Canada on using cannons to propel spacecraft. Actually it seems the Canadians began the experiments in the 1950s but the US sent members of the US Army to work with them and observe. The US even helped fund some of the project when money was tight in Canada. The US began its own program and was launching 26 pound probes to a height of 50 miles. In 1961 the H.A.R.P. program began in earnest. It used a 16 inch gun. It wasn't until 1962 that the gun was mounted in it's permanent home on a coral island, the gun weighed over 40 tons. The first shot was delayed because of the Cuban Missile Crisis as the gun was in Barbados. In 1963 the first shots were fired. A wooden slug rose to 3000 meters straight up. On January 21, a vehicle called a Marlet was launched and reached an altitude of 26 km. The distances grew and a Marlet 2 reached the altitude of 92 km breaking all records for a gun and reaching the upper atmosphere. As all this was going on, the US Army was losing its battle to become the main military force in the US to control space launches. A second test range with its own 16 inch gun was opened near the US - Canadian border. In 1964 it was decided to improve the gun's performance and it's barrel was lengthened. Velocity and altitude were improved but the extension failed after the 11 shot. It did prove however that it was feasible to lengthen the barrel, so the length was doubled. The gun was now 120 feet long and weighed 100 tons. The gun was the largest operational gun in the world. Smaller H.A.R.P. guns were now operating in several locations such as Alaska, Virginia and Quebec. It was beginning to look like this would become the primary method of launch for the space program. The range near the border of the US and Canada was called Highwater. The gun there was extended to 176 feet long and still holds the world's record as the longest big bore gun ever built. Vietnam was beginning to heat up and more and more of the US Army's resources were required there. The Canadian government was falling further behind on funding, the last payment being over 10 months late. In 1966 H.A.R.P. was building an orbital vehicle but had to lay off important personnel due to funding delays. Now the Americans decided that they would erect a gun of their own on American soil to try and insulate themselves from the Canadian politics. A 16 inch gun was erected at Yuma and in 1966 it sent a Marlet 2 vehicle to the astonishing altitude of 180 km, the highest altitude anything shot out of a gun has ever reached. This is about 108 miles straight up. In 1966 the Canadian government withdrew from the H.A.R.P. program. Seeing the Canadian withdrawal from H.A.R.P., and needing all it's funds for the Vietnam war, the US Army used the Canadian withdrawal as an excuse to also withdraw from the project.
All Photos Below are credited © Mark Wade and are used with permission. http://www.astronautix.com/
Gerald Bull, the moving force behind H.A.R.P. was assassinated after he built a huge cannon for Iraq which was bombed by Israel. He said the cannon was a satellite launcher and it was claimed that it couldn't be used as a weapon but apparently others didn't think that this was true.