Space gun
Encyclopedia
A space gun is a method of launching an object into outer space
using a large gun
, or cannon
. It provides a method of non-rocket spacelaunch.
In the HARP Project a U.S. Navy 16 inch (406 mm) 100 caliber gun was used to fire a 180 kilogram slug at 3,600 metres per second, reaching an apogee of 180 kilometres, hence performing a suborbital spaceflight.
However, a space gun has never been successfully used to launch an object into orbit.
experienced by a ballistic
projectile would likely mean that a space gun would be incapable of safely launching human
s or delicate instruments, rather being restricted to freight or ruggedized satellites.
Atmospheric drag also makes it more difficult to control the trajectory of any projectile launched, subjects the projectile to extremely high forces, and causes severe energy losses that may not be easily overcome. The lower troposphere
is the densest layer of the atmosphere, and some of these issues may be mitigated by using a space gun with a "gun barrel
" reaching above it (e.g. a gun emplacement on a mountaintop).
A space gun, by itself, is generally not capable of placing objects into stable orbit around the planet, unless the objects are able to perform course corrections after launch.
If acceptable solutions to these fundamental issues could be achieved, a space gun could offer access to space at an unprecedented low cost.
which ends at the planet's surface at the point of launch or another point. This means that an uncorrected ballistic payload will always strike the planet within its first orbit unless the velocity was so high as to reach or exceed escape velocity
.
Isaac Newton
avoided this objection in his thought experiment by positing an impossibly tall mountain from which his cannon was fired. The projectile, however, would still tend to circle the planet and strike the point of launch.
As a result, all payloads intended to reach a closed orbit would have at least to perform some sort of course correction to create another orbit that does not intersect the planet's surface. In addition a rocket can be used for additional boost, as planned in the Quicklaunch project. The magnitude of such may be small; for instance, the StarTram Generation 1
reference design involves a total of 0.6 km/s of rocket burn to raise perigee
well above the atmosphere when entering a 8 km/s Low Earth Orbit
.
It is conceivable that in a multi-body gravitational system, like the Earth-Moon system, that a trajectory could be found that does not re-intersect the Earth's surface, although these paths would likely not be very simple nor desirable, and would require much more energy.
" of length (
), and the needed velocity (
), the acceleration (
) is provided by the following formula:
For instance, with a space gun with a vertical "gun barrel
" through both the Earth's crust and the troposphere
, totalling ~60 km of length (
), and a velocity (
) enough to escape the Earth's gravity (escape velocity
, which is 11.2 km/s on Earth), the acceleration (
) would theoretically be more than 1000 m/s2, which is more than 100 g-force
s, which is about 3 times the human tolerance to g-forces of maximum 20 to 35 g during the ~10 seconds such a firing would take.
Any doubling of the barrel length would theoretically cut the generated g-force in half while doubling the firing time.
The German V-3 cannon
program (less well known than the V-2 rocket
or V-1 flying bomb
), during the Second World War was an attempt to build something approaching a space gun. Based in the Pas-de-Calais area of France
it was planned to be more devastating than the other Nazi 'Vengeance weapons'. It was destroyed by RAF bombing using 'Tallboy
' blockbuster bombs in July 1944.
On the practical side, the most prominent recent attempt to make a space gun was artillery engineer Gerald Bull
's Project Babylon
, which was also known as the 'Iraqi supergun' by the media. During Project Babylon, Bull used his experience from Project HARP
to build a massive cannon for Saddam Hussein
leader of Ba'athist Iraq
. This gun, had it been completed, would have been the first true space gun capable of launching objects into space. However, Bull was assassinated before the project was completed.
in the 1980s. Developed at Lawrence Livermore Laboratory, it is a light gas gun
and has been used to test fire objects at Mach 9
.
or send bulk materials into space.
Ram accelerator
s have also been proposed as an alternative to light gas guns. Other proposals use electromagnetic techniques for accelerating the payload, such as coilgun
s and railgun
s.
The first publication of the concept may be Newton's cannonball
in the 1728 book A Treatise of the System of the World, although it was primarily used as a thought experiment
regarding gravity.
Perhaps the most famous representation of a space gun is Jules Verne
's novel, From the Earth to the Moon
(made into a silent movie called Le Voyage dans la Lune
), in which astronauts fly to the moon aboard a ship launched from a cannon. Another famous example is the hydrogen accelerator cannon used by the Martians
to launch their invasion in H. G. Wells
' book The War of the Worlds
. Wells also used the concept in the climax of the 1936 movie Things to Come
. The device was featured in films as late as 1967, such as Jules Verne's Rocket to the Moon
.
In the Square (now Square Enix
) video game Final Fantasy VIII
, humans are sent to a space base by the use of hybrid rail
/coil gun
. In the video game Ultima: Worlds of Adventure 2: Martian Dreams, Percival Lowell
builds a space gun to send a ship to Mars
.
In the Nintendo game Paper Mario: The Thousand Year Door the protagonist is fired to the moon from a large cannon powered by the explosion of thousands of anthropomorphic bombs. This is depicted in a somewhat comical fashion.
Additionally, a book about the Halo universe
, Halo: Contact Harvest
included a 'magnetic accelerator cannon(coil gun
)' ,also known as MAC, used as both a surface-to-air/space weapon and to lift objects into space from a planetary surface(known as mass driver).
Gerald Bull
's assassination and the Project Babylon
gun were also the starting point for Frederick Forsyth
's 1994 novel The Fist of God
.
Outer space
Outer space is the void that exists between celestial bodies, including the Earth. It is not completely empty, but consists of a hard vacuum containing a low density of particles: predominantly a plasma of hydrogen and helium, as well as electromagnetic radiation, magnetic fields, and neutrinos....
using a large gun
Gun
A gun is a muzzle or breech-loaded projectile-firing weapon. There are various definitions depending on the nation and branch of service. A "gun" may be distinguished from other firearms in being a crew-served weapon such as a howitzer or mortar, as opposed to a small arm like a rifle or pistol,...
, or cannon
Cannon
A cannon is any piece of artillery that uses gunpowder or other usually explosive-based propellents to launch a projectile. Cannon vary in caliber, range, mobility, rate of fire, angle of fire, and firepower; different forms of cannon combine and balance these attributes in varying degrees,...
. It provides a method of non-rocket spacelaunch.
In the HARP Project a U.S. Navy 16 inch (406 mm) 100 caliber gun was used to fire a 180 kilogram slug at 3,600 metres per second, reaching an apogee of 180 kilometres, hence performing a suborbital spaceflight.
However, a space gun has never been successfully used to launch an object into orbit.
Technical issues
The large g-forceG-force
The g-force associated with an object is its acceleration relative to free-fall. This acceleration experienced by an object is due to the vector sum of non-gravitational forces acting on an object free to move. The accelerations that are not produced by gravity are termed proper accelerations, and...
experienced by a ballistic
Ballistics
Ballistics is the science of mechanics that deals with the flight, behavior, and effects of projectiles, especially bullets, gravity bombs, rockets, or the like; the science or art of designing and accelerating projectiles so as to achieve a desired performance.A ballistic body is a body which is...
projectile would likely mean that a space gun would be incapable of safely launching human
Human
Humans are the only living species in the Homo genus...
s or delicate instruments, rather being restricted to freight or ruggedized satellites.
Atmospheric drag also makes it more difficult to control the trajectory of any projectile launched, subjects the projectile to extremely high forces, and causes severe energy losses that may not be easily overcome. The lower troposphere
Troposphere
The troposphere is the lowest portion of Earth's atmosphere. It contains approximately 80% of the atmosphere's mass and 99% of its water vapor and aerosols....
is the densest layer of the atmosphere, and some of these issues may be mitigated by using a space gun with a "gun barrel
Gun barrel
A gun barrel is the tube, usually metal, through which a controlled explosion or rapid expansion of gases are released in order to propel a projectile out of the end at a high velocity....
" reaching above it (e.g. a gun emplacement on a mountaintop).
A space gun, by itself, is generally not capable of placing objects into stable orbit around the planet, unless the objects are able to perform course corrections after launch.
If acceptable solutions to these fundamental issues could be achieved, a space gun could offer access to space at an unprecedented low cost.
Getting to orbit
A space gun, by itself, is not capable of placing objects into stable orbit. The laws of gravitation make it impossible to reach a stable orbit without an active payload which performs orbital correction burns to change the shape of its orbit after launch. The orbit is a parabolic orbit, a hyperbolic orbit, or part of an elliptic orbitElliptic orbit
In astrodynamics or celestial mechanics an elliptic orbit is a Kepler orbit with the eccentricity less than 1; this includes the special case of a circular orbit, with eccentricity equal to zero. In a stricter sense, it is a Kepler orbit with the eccentricity greater than 0 and less than 1 . In a...
which ends at the planet's surface at the point of launch or another point. This means that an uncorrected ballistic payload will always strike the planet within its first orbit unless the velocity was so high as to reach or exceed escape velocity
Escape velocity
In physics, escape velocity is the speed at which the kinetic energy plus the gravitational potential energy of an object is zero gravitational potential energy is negative since gravity is an attractive force and the potential is defined to be zero at infinity...
.
Isaac Newton
Isaac Newton
Sir Isaac Newton PRS was an English physicist, mathematician, astronomer, natural philosopher, alchemist, and theologian, who has been "considered by many to be the greatest and most influential scientist who ever lived."...
avoided this objection in his thought experiment by positing an impossibly tall mountain from which his cannon was fired. The projectile, however, would still tend to circle the planet and strike the point of launch.
As a result, all payloads intended to reach a closed orbit would have at least to perform some sort of course correction to create another orbit that does not intersect the planet's surface. In addition a rocket can be used for additional boost, as planned in the Quicklaunch project. The magnitude of such may be small; for instance, the StarTram Generation 1
StarTram
StarTram is a proposal for a maglev space launch system. The initial Generation 1 facility would be cargo only, launching from a mountain peak at 3 km to 7 km altitude with an evacuated tube staying at local surface level, raising ≈150,000 tons to orbit annually...
reference design involves a total of 0.6 km/s of rocket burn to raise perigee
Perigee
Perigee is the point at which an object makes its closest approach to the Earth.. Often the term is used in a broader sense to define the point in an orbit where the orbiting body is closest to the body it orbits. The opposite is the apogee, the farthest or highest point.The Greek prefix "peri"...
well above the atmosphere when entering a 8 km/s Low Earth Orbit
Low Earth orbit
A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...
.
It is conceivable that in a multi-body gravitational system, like the Earth-Moon system, that a trajectory could be found that does not re-intersect the Earth's surface, although these paths would likely not be very simple nor desirable, and would require much more energy.
Acceleration
A space gun with a "gun barrelGun barrel
A gun barrel is the tube, usually metal, through which a controlled explosion or rapid expansion of gases are released in order to propel a projectile out of the end at a high velocity....
" of length (
), and the needed velocity (), the acceleration () is provided by the following formula:For instance, with a space gun with a vertical "gun barrel
Gun barrel
A gun barrel is the tube, usually metal, through which a controlled explosion or rapid expansion of gases are released in order to propel a projectile out of the end at a high velocity....
" through both the Earth's crust and the troposphere
Troposphere
The troposphere is the lowest portion of Earth's atmosphere. It contains approximately 80% of the atmosphere's mass and 99% of its water vapor and aerosols....
, totalling ~60 km of length (
), and a velocity () enough to escape the Earth's gravity (escape velocityEscape velocity
In physics, escape velocity is the speed at which the kinetic energy plus the gravitational potential energy of an object is zero gravitational potential energy is negative since gravity is an attractive force and the potential is defined to be zero at infinity...
, which is 11.2 km/s on Earth), the acceleration (
) would theoretically be more than 1000 m/s2, which is more than 100 g-forceG-force
The g-force associated with an object is its acceleration relative to free-fall. This acceleration experienced by an object is due to the vector sum of non-gravitational forces acting on an object free to move. The accelerations that are not produced by gravity are termed proper accelerations, and...
s, which is about 3 times the human tolerance to g-forces of maximum 20 to 35 g during the ~10 seconds such a firing would take.
Any doubling of the barrel length would theoretically cut the generated g-force in half while doubling the firing time.
Practical attempts
V-3 cannon
The V-3 was a German World War II supergun working on the multi-charge principle whereby secondary propellant charges are fired to add velocity to a projectile....
program (less well known than the V-2 rocket
V-2 rocket
The V-2 rocket , technical name Aggregat-4 , was a ballistic missile that was developed at the beginning of the Second World War in Germany, specifically targeted at London and later Antwerp. The liquid-propellant rocket was the world's first long-range combat-ballistic missile and first known...
or V-1 flying bomb
V-1 flying bomb
The V-1 flying bomb, also known as the Buzz Bomb or Doodlebug, was an early pulse-jet-powered predecessor of the cruise missile....
), during the Second World War was an attempt to build something approaching a space gun. Based in the Pas-de-Calais area of France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
it was planned to be more devastating than the other Nazi 'Vengeance weapons'. It was destroyed by RAF bombing using 'Tallboy
Tallboy bomb
The Tallboy or Bomb, Medium Capacity, 12,000 lb, was an earthquake bomb developed by the British aeronautical engineer Barnes Wallis and deployed by the RAF in 1944...
' blockbuster bombs in July 1944.
On the practical side, the most prominent recent attempt to make a space gun was artillery engineer Gerald Bull
Gerald Bull
Gerald Vincent Bull was a Canadian engineer who developed long-range artillery. He moved from project to project in his quest to launch economically a satellite using a huge artillery piece, to which end he designed the Project Babylon "supergun" for the Iraqi government...
's Project Babylon
Project Babylon
Project Babylon was a project commissioned by the Iraqi president Saddam Hussein to build a series of superguns. The design was based on research from the 1960s Project HARP led by the Canadian artillery expert Gerald Bull...
, which was also known as the 'Iraqi supergun' by the media. During Project Babylon, Bull used his experience from Project HARP
Project HARP
Project HARP, short for High Altitude Research Project, was a joint project of the United States Department of Defense and Canada's Department of National Defence created with the goal of studying ballistics of re-entry vehicles at low cost; whereas most such projects used expensive rockets, HARP...
to build a massive cannon for Saddam Hussein
Saddam Hussein
Saddam Hussein Abd al-Majid al-Tikriti was the fifth President of Iraq, serving in this capacity from 16 July 1979 until 9 April 2003...
leader of Ba'athist Iraq
Ba'athist Iraq
The History of Iraq , referred to as Ba'athist Iraq, covers the period of the Arab Socialist Ba'ath Party's rule over Iraq. Ba'athist rule in Iraq first occurred briefly in 1963 under Ahmed Hassan al-Bakr until overthrown that same year. Ba'athism was restored to power five years later after...
. This gun, had it been completed, would have been the first true space gun capable of launching objects into space. However, Bull was assassinated before the project was completed.
Super High Altitude Research Project
Since Bull's death, few have seriously attempted to build a space gun. Perhaps most promisingly, the US Ballistic Missile Defense program sponsored the Super High Altitude Research ProjectSuper High Altitude Research Project
The Super High Altitude Research Project was a U.S. government project conducting research into the firing of high-velocity projectiles high into the atmosphere using a two stage light gas gun, with the ultimate goal of propelling satellites into Earth orbit...
in the 1980s. Developed at Lawrence Livermore Laboratory, it is a light gas gun
Light gas gun
The light-gas gun is an apparatus for physics experiments, a highly specialized gun designed to generate very high velocities. It is usually used to study high speed impact phenomena , such as the formation of impact craters by meteorites or the erosion of materials by micrometeoroids...
and has been used to test fire objects at Mach 9
Mach number
Mach number is the speed of an object moving through air, or any other fluid substance, divided by the speed of sound as it is in that substance for its particular physical conditions, including those of temperature and pressure...
.
Quicklaunch
One of the lead developers John Hunter has since founded the Jules Verne Launcher Company in 1996 and the Quicklaunch company.He now seek to raise $500 million to build one that could refuel a propellant depotPropellant depot
An orbital propellant depot is a cache of propellant that is placed on an orbit about the Earth or another body to allow spacecraft to be fuelled in space. Launching a spacecraft separately from some of its propellant enables missions with more massive payloads...
or send bulk materials into space.
Ram accelerator
Ram accelerator
A ram accelerator has the same function as a gun; i.e., it is a device for accelerating projectiles; however, it is entirely different in that jet-engine-like propulsion cycles utilizing ramjet and/or scramjet combustion processes are used to accelerate a projectile to extremely high speeds...
s have also been proposed as an alternative to light gas guns. Other proposals use electromagnetic techniques for accelerating the payload, such as coilgun
Coilgun
A coilgun is a type of projectile accelerator that consists of one or more coils used as electromagnets in the configuration of a synchronous linear motor which accelerate a magnetic projectile to high velocity...
s and railgun
Railgun
A railgun is an entirely electrical gun that accelerates a conductive projectile along a pair of metal rails using the same principles as the homopolar motor. Railguns use two sliding or rolling contacts that permit a large electric current to pass through the projectile. This current interacts...
s.
In fiction
Newton's cannonball
Newton's cannonball was a thought experiment Isaac Newton used to hypothesize that the force of gravity was universal, and it was the key force for planetary motion...
in the 1728 book A Treatise of the System of the World, although it was primarily used as a thought experiment
Thought experiment
A thought experiment or Gedankenexperiment considers some hypothesis, theory, or principle for the purpose of thinking through its consequences...
regarding gravity.
Perhaps the most famous representation of a space gun is Jules Verne
Jules Verne
Jules Gabriel Verne was a French author who pioneered the science fiction genre. He is best known for his novels Twenty Thousand Leagues Under the Sea , A Journey to the Center of the Earth , and Around the World in Eighty Days...
's novel, From the Earth to the Moon
From the Earth to the Moon
From the Earth to the Moon is a humorous science fantasy novel by Jules Verne and is one of the earliest entries in that genre. It tells the story of the president of a post-American Civil War gun club in Baltimore, his rival, a Philadelphia maker of armor, and a Frenchman, who build an enormous...
(made into a silent movie called Le Voyage dans la Lune
Le Voyage dans la Lune
A Trip to the Moon is a 1902 French black-and-white silent science fiction film. It is based loosely on two popular novels of the time: Jules Verne's From the Earth to the Moon and H. G. Wells' The First Men in the Moon....
), in which astronauts fly to the moon aboard a ship launched from a cannon. Another famous example is the hydrogen accelerator cannon used by the Martians
Martian (War of the Worlds)
The Martians, also known as the Invaders, are the fictional race of extraterrestrials from the H.G. Wells novel The War of the Worlds. They are the antagonists of the novel, and their efforts to exterminate the populace of Earth and claim the planet for themselves drive the plot and present...
to launch their invasion in H. G. Wells
H. G. Wells
Herbert George Wells was an English author, now best known for his work in the science fiction genre. He was also a prolific writer in many other genres, including contemporary novels, history, politics and social commentary, even writing text books and rules for war games...
' book The War of the Worlds
The War of the Worlds
The War of the Worlds is an 1898 science fiction novel written by H. G. Wells.The War of the Worlds may also refer to:- Radio broadcasts :* The War of the Worlds , the 1938 radio broadcast by Orson Welles...
. Wells also used the concept in the climax of the 1936 movie Things to Come
Things to Come
Things to Come is a British science fiction film produced by Alexander Korda and directed by William Cameron Menzies. The screenplay was written by H. G. Wells and is a loose adaptation of his own 1933 novel The Shape of Things to Come and his 1931 non-fiction work, The Work, Wealth and Happiness...
. The device was featured in films as late as 1967, such as Jules Verne's Rocket to the Moon
Jules Verne's Rocket to the Moon
Jules Verne's Rocket to the Moon is a 1967 British science fiction comedy film directed by Don Sharp and produced by Harry Alan Towers...
.
In the Square (now Square Enix
Square Enix
is a Japanese video game and publishing company best known for its console role-playing game franchises, which include the Final Fantasy series, the Dragon Quest series, and the action-RPG Kingdom Hearts series...
) video game Final Fantasy VIII
Final Fantasy VIII
is a role-playing video game released for the PlayStation in 1999 and for Windows-based personal computers in 2000. It was developed and published by Square as the Final Fantasy series' eighth title, removing magic point-based spell-casting and the first title to consistently use realistically...
, humans are sent to a space base by the use of hybrid rail
Railgun
A railgun is an entirely electrical gun that accelerates a conductive projectile along a pair of metal rails using the same principles as the homopolar motor. Railguns use two sliding or rolling contacts that permit a large electric current to pass through the projectile. This current interacts...
/coil gun
Coilgun
A coilgun is a type of projectile accelerator that consists of one or more coils used as electromagnets in the configuration of a synchronous linear motor which accelerate a magnetic projectile to high velocity...
. In the video game Ultima: Worlds of Adventure 2: Martian Dreams, Percival Lowell
Percival Lowell
Percival Lawrence Lowell was a businessman, author, mathematician, and astronomer who fueled speculation that there were canals on Mars, founded the Lowell Observatory in Flagstaff, Arizona, and formed the beginning of the effort that led to the discovery of Pluto 14 years after his death...
builds a space gun to send a ship to Mars
Mars
Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...
.
In the Nintendo game Paper Mario: The Thousand Year Door the protagonist is fired to the moon from a large cannon powered by the explosion of thousands of anthropomorphic bombs. This is depicted in a somewhat comical fashion.
Additionally, a book about the Halo universe
Halo (series)
Halo is a multi-million dollar science fiction video game franchise created by Bungie and now managed by 343 Industries and owned by Microsoft Studios. The series centers on an interstellar war between humanity and a theocratic alliance of aliens known as the Covenant...
, Halo: Contact Harvest
Halo: Contact Harvest
Halo: Contact Harvest is a science fiction novel by Joseph Staten, set in the Halo universe. Staten is a longtime employee of Bungie, the developer of the Halo video game series; he directed the cut scenes in the video games and is a major contributor to Halos storyline...
included a 'magnetic accelerator cannon(coil gun
Coilgun
A coilgun is a type of projectile accelerator that consists of one or more coils used as electromagnets in the configuration of a synchronous linear motor which accelerate a magnetic projectile to high velocity...
)' ,also known as MAC, used as both a surface-to-air/space weapon and to lift objects into space from a planetary surface(known as mass driver).
Gerald Bull
Gerald Bull
Gerald Vincent Bull was a Canadian engineer who developed long-range artillery. He moved from project to project in his quest to launch economically a satellite using a huge artillery piece, to which end he designed the Project Babylon "supergun" for the Iraqi government...
's assassination and the Project Babylon
Project Babylon
Project Babylon was a project commissioned by the Iraqi president Saddam Hussein to build a series of superguns. The design was based on research from the 1960s Project HARP led by the Canadian artillery expert Gerald Bull...
gun were also the starting point for Frederick Forsyth
Frederick Forsyth
Frederick Forsyth, CBE is an English author and occasional political commentator. He is best known for thrillers such as The Day of the Jackal, The Odessa File, The Fourth Protocol, The Dogs of War, The Devil's Alternative, The Fist of God, Icon, The Veteran, Avenger, The Afghan and The Cobra.-...
's 1994 novel The Fist of God
The Fist of God
The Fist of God is a 1994 novel by Frederick Forsyth, mixing known fact with fiction to tell a story of the coalition forces in the Persian Gulf War racing against time to discover the true nature of Saddam Hussein's secret weapon, 'The Fist of God.'...
.
See also
- Newton's cannonballNewton's cannonballNewton's cannonball was a thought experiment Isaac Newton used to hypothesize that the force of gravity was universal, and it was the key force for planetary motion...
- SHARPSuper High Altitude Research ProjectThe Super High Altitude Research Project was a U.S. government project conducting research into the firing of high-velocity projectiles high into the atmosphere using a two stage light gas gun, with the ultimate goal of propelling satellites into Earth orbit...
- Quicklaunch
- StarTramStarTramStarTram is a proposal for a maglev space launch system. The initial Generation 1 facility would be cargo only, launching from a mountain peak at 3 km to 7 km altitude with an evacuated tube staying at local surface level, raising ≈150,000 tons to orbit annually...
- Space elevatorSpace elevatorA space elevator, also known as a geostationary orbital tether or a beanstalk, is a proposed non-rocket spacelaunch structure...
- Launch loopLaunch loopA launch loop or Lofstrom loop is a proposed system for launching objects into space orbit using a moving cable-like system attached to the earth at two ends and suspended above the atmosphere in the middle...
- LightcraftLightcraftA lightcraft is a space- or air-vehicle driven by laser propulsion. Laser propulsion is currently in early stages of development. Lightcraft use an external source of laser or maser energy to provide power for producing thrust. The laser/maser energy is focused to a high intensity in order to...
- Space fountainSpace fountainA space fountain is a proposed form of space elevator that does not require the structure to be in geostationary orbit, and does not rely on tensile strength for support. In contrast to the original space elevator design , a space fountain is a tremendously tall tower extending up from the ground...
- Tether propulsion
- Non-rocket spacelaunchNon-rocket spacelaunchNon-rocket space launch is a launch into space where some or all needed speed and altitude is provided by non-rocket means, rather than simply using conventional chemical rockets from the ground. A number of alternatives to rockets have been proposed...