Since the very early days of science fiction, many authors and thinkers have dreamed up some interesting, dare we say, almost insane methods that humans might one day explore the cosmos. Some of these have become a reality, like rockets, but by far one of the most outlandish is something called a "space gun".
Effectively enormous, powerful, and cannon-like devices, these enormous pieces of engineering have been considered for decades. But, what exactly are they, and how would they work?
Let's take a look.
What are space guns?
As you can probably work out from the name, space guns are a proposed method of launching things into outer space using a large projectile launcher. Most designs are enormous guns or cannons, and were perhaps first proposed by none other than Jules Verne in his sci-fi classic "From the Earth to the Moon".
In Verne's vision of future space travel, an American post-Civil War Society, called the Baltimore Gun Club, embark on an outrageous attempt to go to the Moon. Club members attempt to assemble a gigantic Columbiad (a type of smoothbore cannon) to act as an enormous firearm big enough to launch human beings into space.
Interestingly, and considering the lack of genuine scientific study into such an endeavor, Verne even made some attempts at making some basic calculations on the requirements of such a gun. Despite his lack of empirical data, his estimations have proven to be remarkably accurate.
Unlike the scenario in Jules Verne's fiction, it is highly unlikely that such a technology, if devised, could ever realistically be used to launch human beings into space. For non-living, robust objects, on the other hand, this technology might have some utility.
With regards to being used as a means of transporting humans into space, the G-forces involved to enable a human-carrying projectile to reach escape velocity would be too much for the human body to endure. For other objects, like freight or particularly robust/rugged satellites, etc, space guns could be an interesting and cheaper alternative to rockets.
However, the incredible forces involved in this kind of delivery system can limit the kinds of things that could realistically be fired into space. That being said, the G-forces involved in space gun launches, according to some, are "often over-exaggerated".
"Military artillery shells today have GPS, laser-guidance optics, and electronics that survive these accelerations, so it can be done. Obviously, not everything can be launched this way, but the gun launch is well suited for launching fuel and building materials," explained Andrew Higgins, a professor at the Department of Mechanical Engineering at McGill University, Canada to the BBC.
The concepts for this type of device vary considerably, from using combustion (as in a conventional firearm), high-pressure gases, even railgun-like versions. Pneumatic launch systems, for example, accelerate the payload "bullet" along a very long barrel using air pressure produced by a ground-based turbine (or other means).
For ballistic-type space guns, the concept is well established and even somewhat proven. However, the main problem for reaching space with this technology is finding ways to maintain the very high velocities needed to reach escape velocity. The main enemy here for the technology is air resistance and aerothermal heating that can, and will, significantly degrade any projectile's velocity over time.
“Punching through the lower (denser) part of the atmosphere at high speed is an intense heat transfer problem, but ablative coatings and heat shields on the nose of the projectile should be up to the job,” added Higgins.
While many of the earlier attempts to make a space gun a reality are all now effectively defunct, the reality of space guns appears to be over. However, according to experts like Higgins, it could see a resurgence in the future.
“Rather than throwing away the first stage of a rocket, using a large gun for the first stage would enable this hardware to be reused and easily serviced,” he said.
Let's take a look at some notable real-world attempts at making a working space gun.
1. The Germans built something similar in WW2 - except for war, not space exploration
During the Second World War, Germany made a series of experimental weapons platforms in an attempt to turn the tide of battle in their favor. Called the "Vengeance Weapons", the program consisted of the well-known V1 flying bomb, and the world's first long-range ballistic missile, the V2 rocket.
But, there was a third weapon called the V-3. It was also known as the Hochdruckpumpe ("High-Pressure Pump," or HDP for short) — a code name intended to hide the real purpose of the project. It was also known as Fleißiges Lieschen ("Busy Lizzie").
This weapon was to be used to fire projectiles over incredibly long ranges from strategic underground locations across Europe.
The first test facility was built in the Pas-de-Calais area of France, in a top-secret subterranean facility hidden from view at the surface. Within the facility, a series of extremely long "barrels" were built in specially angled chambers which were trained in London, UK.
Each was able to launch a 310lb (140kg), 5.9-inch, (15cm) diameter shell over a distance of well over 55 miles (88km). The shells were fired by multi-charge ignition propulsion, where a series of secondary propellant charges were placed along the barrel to accelerate the projectile to incredibly high velocities.
As the projectile passed each secondary charge, it would be triggered, discharging more hot gas behind the projectile, pushing it further forward, and accelerating the projectile as it went. Solid-fuel rocket boosters were used for this purpose. Compared to explosive charges, they were much safer to handle and easier to install and replace.
The charges were arranged in symmetrical pairs along the length of the barrel, angled towards the "muzzle" to maximize their impact on the base of the projectile as it passed.
Interestingly, the barrel and side chambers were designed as identical sections to simplify production and allow damaged sections to be replaced. It also meant they could be constructed and potentially moved in sections with relative ease.
The inner surface of the barrel was smooth, and the projectiles used consisted of fin-stabilized shells that depended upon aerodynamic forces rather than gyroscopic forces to prevent tumbling (distinct from conventional rifled weapons which cause the projectile to spin). This setup resulted in a lower drag coefficient, and a more stable flight once launched.
The V-3, if ever completed and successful, would have been able to easily bombard London from the relative safety of German-occupied France at a rate of one shell every six seconds. There would have been no reliable defense or countermeasure against such an attack beyond destroying the weapon.
The whereabouts of the weapon were discovered and a bombing raid was arranged to knock out the facility before it could be completed. The site still exists to this day and is now a museum where visitors can inspect what remains of the facility and guns.
Similar but smaller versions of the weapon were, however, used to bombard Luxembourg from December 1944 to February 1945.
The weapon, with a good deal of modification and development, could have conceivably also been adapted for use as a kind of space gun.
2. The U.S. once developed an anti-ballistic missile space gun
Back in the 1980s, the United States once attempted to develop a ground-based gun that could target and knock out ballistic missiles in low-Earth orbit. Developed as part of the Super High Altitude Research Project (SHARP), it was never completed.
While it was in development, the gun was the largest gas gun in the world at the time.
The system comprised of a light-gas gun that was, if ever fully developed, intended to destroy targets traveling in excess of Mach 9 or 6,905 mph (11,113 kph). The space gun was developed at the Lawrence Livermore Laboratory and used compressed gas to accelerate projectiles to extremely high velocities.
Similar technology is used in various physics experimental apparatus to research the effects of high-velocity impacts from things like meteorites, etc. It works in a similar fashion to spring-piston airguns by using a larger piston to force gas through a barrel.
SHARP, however, rather than consisting of a single long barrel, consisted of an L-shaped design with two separate sections. A methane gas mixture is ignited behind the piston and the resultant explosion rapidly drives the piston down the barrel and compresses a pre-pressurized gas in the barrel. A small projectile is inserted into the launch tube and is then driven down the barrel at extremely high velocities. The gun's enormous recoil was then absorbed by specially designed rail-mounted sleds.
SHARP, when tested, was able to launch its 11-lb (5kg) projectiles at speeds of around 6,700 mph (3 km/s) to 450 km in altitude. Further tests were planned to elevate the barrel towards space and improve the design to enable it to fire projectiles in excess of Mach 21, however, the project was later canceled in the early-1990s.
3. SHARP could have led to an even larger "Jules Verne Launcher"
As impressive as SHARP was during its day, it would have been only the first step to an even larger, and much more impressive space gun called the "Jules Verne Launcher". This would have been an even larger version of SHARP with an 11,500 foot long (3,500m) barrel.
According to a study at the time, by the team behind SHARP, the "Jules Verne Launcher" would have been able to deliver "3.3 metric tons to a 500 km low earth orbit."
Impressive enough, but the scientists who proposed the project continued to make some bold predictions about the gun, writing, "our results indicated that the JVL will be able to deliver 1000 metric tons of payload to LEO yearly. The cost will be 5% of the best US rocket delivery cost. This technology will enable the next phase of [our] exploration of space."
Designed in the early-1990s, the space gun would have been used to launch satellites into orbit without the need for a rocket. With a potential cost of around $1 billion, the project failed to drum up enough support to ever get the funding.
For this reason, among others, it never really left the drawing board.
4. "Quicklaunch" is an underwater variation on the theme of space guns
In the aftermath of the cancellation of SHARP, one of its critical team members, John Hunter, decided to continue to develop the idea in the private sector. To this end, he founded the Jules Verne Launcher Company (now defunct) in the mid-1990s, and then later the Quicklaunch Company (also now defunct).
These private ventures continued to work on the concept while also bidding for private investment, with the company able to raise around $500 million in 2012. The idea for the "Quicklauncher" space gun was to complete a large light-gas gun capable of delivering to a space-based depot fuel or other bulk materials capable of surviving the extreme forces produced by this kind of space delivery system.
What's more, other proposals for the system suggested it could have been deployed in a large body of water, roughly 600 feet (183m) down. The gun would have been around 1,300 feet long (400m) and capable of shooting payloads of around 100-lbs (45kg) into low-Earth orbit.
To make the most of the slingshot effect, the space gun would be best situated as close to the equator as possible and should be able to fire off up to ten launch vehicles a day.
According to Hunter, the project never really got going because of “internal issues”. In 2016, he told the BBC “It’s no more. There’s some intellectual property there but the members have split up.”
However, Hunter believed his approach went a long way to adequately reducing the cost of taking payloads to space. He has reportedly encouraged anyone with enough money and motivation to take up the mantle and reinvestigate the technology, although he added that the progress made by Space X makes it unlikely that any supergun projects would restart.
“For now, with the work, Elon Musk is doing with Space X there’s no room for a project like Quicklaunch,” Hunter told the BBC. “But I’m happy as a clam for Elon, I really am, because it takes the monkey off my back.”
5. Saddam Husein even had a go at making one, albeit for different reasons
Of all the attempts to realize Jules Verne's vision, perhaps the closest was "Project Babylon," developed in the late-1980s. Developed by the artillery engineer Gerald Bull, the gun was developed for use by the Iraqi Government under Saddam Hussein.
Gerald Bull was a Canadian engineer and inventor who had high ambitions, pun intended, to develop specialist large guns which could fire things like satellites into orbit from bases on terra firma.
In the early-1980s, Bull was contacted by Iraqi officials to help them develop special artillery for the Iran-Iraq war. At this time, Saddam Husein was Iraq's defense secretary and he had some ambitions to develop an Iraqi space program.
Bull was apparently intrigued by the possibility, notably the space program part, and agreed. To this end, he was given a $25 million budget to develop what would become Project Babylon.
Throughout the late-1980s, three superguns were developed, including two full-sized "Big Babylon" 39.37-inch (1000mm) caliber guns and a prototype 13.87-inch (350mm) caliber gun called "Baby Babylon". The former, if completed, would have been 512 feet (156 meters) long. It would also have weighed 1,510 tonnes - far too big to be transportable. To this end, it would have been mounted at a 45-degree angle on a hillside.
Using a special propellant, it has been estimated that the gun could have fired a 1322.77-lb (600kg) projectile at a range of 621 miles (1,000 km), give or take. Alternatively, the gun could be used to launch a 4409.245-lb (2,000kg) rocket-assisted projectile carrying a 441-lb (200kg) satellite.
Bull was actually assassinated before the project could ever be completed. To this day, little is known which country, or person, actually committed the act, but it has been strongly suggested that Israel's Mossad is the most likely candidate. Israel has officially denied any connection to the event, and the United States, United Kingdom, South Africa, and senior figures in Iraq itself also had reasons to have ordered the hit.
After Bull's death, the project effectively stalled and parts destined for the supergun are on permanent display at the Royal Armories collection at Fort Nelson in Hampshire, England, UK.
For now, the concept of space guns is pretty much dead in the water. The leaps and bounds being made by private rocket companies like SpaceX are effectively crowding out the potential benefits of space guns for the moment.
But, never say never. There is the remote possibility that private ventures somehow "drop the ball", leaving some room for space guns to make a return.
However, the technology that underpins most space gun designs is still very much in existence today - albeit on a much smaller scale. Various universities use them on a regular basis for testing high-velocity impacts on things like satellite "armor".
These devices effectively analyze the effects of high-velocity space debris to find ways to better protect satellites in orbit. Space guns, or rather high-powered gas guns, are the only realistic way of simulating these events on Earth.
Will we see space guns see a revival in the future? Much like Norman Peale's famous quote "shoot for the moon. Even if you miss, you'll land among the stars," it might just be worth a shot.