Would launching payloads from planes or Maglev platforms into space be more efficient/cheaper than using multi-stage launch vehicles?

Air-launching is not unheard of, but is limited to smaller payloads due to the required size of the carrier aircraft. As far as Maglev platforms, see The Orbital Sciences Corportation Pegasus is launched from a converted L-1011 airliner: The suborbital Scaled Composites SpaceShipOne and SpaceShipTwo are also launched from aircraft: ...and the suborbital X-15 spaceplane: Check out http://selenianboondocks.com/2008/01/orbital-access-methodologies-part-i-air-launched-ssto/ for a thorough technical discussion of air-launched orbital spacecraft.

The name for launching (or firing) something with electromagnetic forces is a railgun. The idea of using railguns to launch something into space has been suggested and explored. (Interesting side note: Jules Verne suggested a similar "gun" mechanism to launch to the Moon in his 1865 novel "From the Earth to the Moon." However Verne suggested guncotton rather than E-M- forces as an accellerant.) There are many challenges, though. Since all of the kinetic energy to reach orbit has to be supplied by the railgun, the acceleration will be fierce, much higher than in current rockets. It would be unlikely that you could design any complex mechanisms or electronics that would withstand these accelerations. Humans or other organisms would not stand a chance to survive such a launch. As a mechanism to launch raw materials (such as iron and steel to build a space station, ship etc.) it could work well. The most likely place to see this happen may be to launch minerals mined from a Near Earth Asteroid (NEA) to Earth orbit. The velocity delta required will be much lower than for launching something from Earth to orbit.

There are a lot of interesting factors at play here. I hope you enjoy the following geekery. As Daniel mentioned, a stable orbit requires both altitude and horizontal velocity. There are several ways that rocket scientists eek out benefits that will reduce fuel requirements or increase maximum payload. As it turns out, getting a slight altitude boost doesn't help the equation that much. Here are a few relevant technologies and tactics: Launch on the Equator - The closer to the Equator you launch, the more you can take advantage of the Earth's spin to give you a head start at reaching orbital velocity. Sea Launch (http://www.sea-launch.com/) operates a floating platform that can be positioned in the ocean at the Equator. Not directly pertinent to the question, but launching at the Equator also gives a 15-20% payload advantage for satellites destined for geostationary orbit, because payloads launched from Cape Canaveral (or anywhere not on the Equator) would require a 'plane change' orbital maneuver to bring the axial tilt of their orbit down to zero (relative to the Earth's rotation). That costs fuel that can otherwise be traded for additional payload weight. Launch near sea level for safety - While most launch sites are not that far from sea level, this is often because it's safer to launch over the ocean rather than have a launch track that goes over potentially populated areas. This is why the USA relies predominantly on three launch sites in California (Vandenberg AFB), Florida (Cape Canaveral AFB), and Alaska (Kodiak Launch Complex, a commercially operated spaceport). Each gives a range of launch inclinations that result in thousands of miles of ground track over oceans, minimizing risk of peripheral damage if the launch goes awry. Side note: A Space Shuttle launch pad was constructed in California's Vandenberg AFB that would allow Space Shuttles to launch into a polar orbit, but the project was shelved just nine months before its christening launch when Challenger exploded in 1986. Launch at a high altitude - The idea of bypassing as much of the Earth's atmosphere as possible isn't a new one. Most notably, Orbital Systems developed the Pegasus system (http://www.orbital.com/spacelaunch/pegasus/), a rocket that is strapped to the bottom of an L-1011 jetliner, where it is taken up to 39,000 feet before it's released at 624MPH. Five seconds after its horizontal release, the Pegasus rocket fires, using its delta wing for lift before slowly increasing its angle of attack. Pegasus has been shown to be very reliable and fuel efficient, but because of the nature of the launch device, it's only practical for smaller payloads. The dreaded 'Max-Q' - The biggest stress on a launch vehicle happens when it has high velocity while going through a dense atmosphere. When you watch a Shuttle launch and they say 'now passing through 'Max-Q' or 'maximum dynamic pressure', that's the point when the strongest exterior forces are being applied to the vehicle. From a structural standpoint, this is the most dangerous point in the launch sequence. In fact, during Shuttle launches, the three main engines would throttle down to 70% around the area of Max-Q to reduce the total stress on the airframe at that point. This is relevant to a discussion of a railgun launch because in that sort of launch the highest velocity in the first stage is right when the vehicle leaves the gun, which is also when the atmosphere is thickest. This results in a very undesirable Max Q. (Note: As I re-read your question I realize you mean that the top of the gun is 1km up, so this isn't as relevant to your scenario, as it would be to a horizontal railgun, but I hope it's interesting anyhow.) A rocket to withstand push *and* pull is heavier - Rockets are designed to support a 'push' thrust and to withstand the air pressure they're pushing through during launch. A railgun would accelerate the craft by accelerating parts of the craft which in turn would 'pull' the rest of the craft. A craft built to withstand 3Gs of 'towing' thrust as well as 3Gs of 'pushing' thrust would probably have to be heavier to give the added structural integrity. An argument could be made that all the ship affected by the railgun could be in the lowest part of the ship, and that big piece of heavy metal could be ejected immediately following the railgun portion. Maybe that could work. An ejected piece of metal running at 600MPH sounds like an interesting safety challenge. Or maybe it could simply be part of a launch cradle that's actually an integrated part of the railgun. Which brings me to a related idea currently undergoing testing: Railgun catapults on aircraft carriers - Replacing a steam powered catapult with a railgun to accelerate planes off an aircraft carrier has been a dream for a long time, and it's finally coming true. After successful prototype tests on a specially-built prototype runway last year, the Navy is incorporating railgun catapults into the USS Gerald Ford, an aircraft carrier currently under construction. Details here: http://www.defenseindustrydaily.com/EMALS-Electro-Magnetic-Launch-for-Carriers-05220/ In the end, I think the most basic answer is that getting a boost to 600MPH at 1km isn't a big enough benefit to justify the added complexity to the launch system or probable infrastructure changes to the launch vehicle. The viability goes up a huge amount if you don't have to deal with atmosphere though. There's been a lot of thought put into 'Mass Drivers' on the Moon (http://www.defenseindustrydaily.com/EMALS-Electro-Magnetic-Launch-for-Carriers-05220/), basically horizontal railguns many miles long. Because the atmosphere isn't a problem you can launch horizontally until you reach escape velocity. Because so much of the acceleration can be achieved by the first stage (the railgun stage) you wouldn't need to carry much fuel (which can't be propelled electromagnetically so must be pushed by the metal parts of the craft) which, along with the absence of atmospheric drag, eliminates much of the Earth-bound problems. A big drawback to a mass driver of this kind is that it points one way. As the moon orbits the earth and sun the gun will carve a convoluted cone of possible launch windows, but you'd either need several guns for different mission profiles, a fair amount of maneuvering fuel to alter a flight path after launch, or a gun which could rotate. Not an easy task for a gun several miles long on the moon. A fourth option would be a mass driver built on one of the lunar poles, facing the earth. After launch, the spacecraft could expend just a small amount of fuel to change its course to 'miss the earth' from a specific vector, using the direction and degree diverted to modify the earth's slingshot effect to give a much wider range of possible flight paths. But then, the course-change stage might fail after launch, and you've got a heavy metal object aimed straight at the earth at high speed. That's why there would be three launch windows every 28 days to coincide with the Pacific, Atlantic and Indian oceans facing the gun. Sorry this answer ranged out a bit from the original question. I hope you found it entertaining.

My limited understanding of the matter is that horizontal speed is what makes an orbit. Altitude is a relatively small factor. A point I know I often belabour, when answering this sort of thing, is that (as an example) the International Space Station travels around the Earth at over 27,000kmh, and if it did not, it would drop like a stone. So, your launch mechanism is achieving less than 1/60th the horizontal motion needed to achieve an orbit. It is also doing so within the densest part of the atmosphere, so my instincts tell me that it would not be as efficient as simply using a multi-stage rocket and doing the horizontal bit after it was outside the atmosphere. A better option, would probably be, to find a way of ram-jetting atmospheric oxygen, so that less of that part of the burn needed to be carried upward. The British Skylon projects claims to have fixed that, but at the moment Skylon is nothing more than a rather cheap-looking CG animation, produced by someone who got bored halfway through trying to simulate an SR71 Blackbird.

See http://research.lifeboat.com/ieee.em.pdf Abstract—Many advances in electromagnetic (EM) railgun and power supply technology have been made in recent years. Laboratory experiments with railguns have demonstrated muzzle velocities of 2–3 km/s and muzzle energies 8 MJ. The extension of this technology to the muzzle velocities ( 7500 m/s) and energies ( 10 GJ) needed for the direct launch of payloads into orbit is very challenging, but may not be impossible. For launch to orbit, even long launchers ( 1000 m) would need to operate at accelerations 1000 gees to reach the required velocities, so that it would only be possible to launch rugged payloads, such as fuel, water, and material. A railgun system concept is described here and technology development issues are identified. Estimated launch costs could be attractively low ( $600/kg) compared with the Space Shuttle ( $20 000/kg), provided that acceptable launch rates can be achieved.

There is a project called "Star Tram" that is aiming to build a maglev space launch using a vacuum tube with superconducting electric propulsion.  Smaller versions of the system can constructed on a mountain slope and used to launch cargo with high acceleration rates.  A human rated system would use superconducting magnets to levitate the tube to an altitude of 20km.  The design has been peer reviewed and found to be technically feasible.  See http://startram.com and http://startramfans.com for more details. The estimated launch costs are less than $100 per kg to low Earth orbit.

i wanted to make a correction to the "real name" and purpose of what people are calling a rail gun. it was invented by gerard o'neills organization the space studies institute. it was called a "mass driver."  its purpose was to move materials off the moon for construction of free floating colonies. its worth noting that o'neill ask for funding from the defense department and it was denied.  after he demonstrated it the military became interested and "invented" a knock off they named a "rail gun."  from space settlements: a design study. 1975 http://settlement.arc.nasa.gov/75SummerStudy/Table_of_Contents1.html "The alternative method, which is the one chosen for this design,  involves an electromagnetic mass accelerator. Small payloads are  accelerated in a special bucket containing super conducting coil magnets.  Buckets containing tens of kilograms of compacted lunar material are  magnetically levitated and accelerated at 30 g by a linear, synchronous  electric motor. Each load is precisely directed by damping the vibrations  of the bucket with dashpot shock absorbers, by passing the bucket along  an accurately aligned section of the track and by making magnetic  corrections based on measurements using a laser to track the bucket with  great precision during a final draft period. Alignment and precision are  the great problems of this design since in order to make efficient  collection possible, the final velocity must be controlled to better than  l0^-3 m/s. Moreover, the system must launch from 1 to 5 buckets per second  at a steady rate over long periods of time, so the requirements for  reliability are great. This system is considerably more massive than the  gas gun. More details about it are given in the next chapter." the space studies institute http://ssi.org