- #1
maglifter
- 22
- 0
Forget space elevators and pipelines to space, the tramway is far more realistic.
A big 1500 mile tube suspended with superconducting cables, floating in the air, reaching 70000ft, containing a maglev track.
http://www.startram.com/main.html
"StarTram - Ultra Low-Cost To Orbit
The current cost of launching payloads to LEO orbit is very high, on the order of $10,000 per kilogram. The launch costs to GTO and GEO are considerably greater. Major research efforts are underway on advanced reusable launch vehicles that could potentially reduce launch costs to LEO to ~$1000 per kilogram. However, the technology for these reusable vehicles is very demanding and it is not clear whether this goal can be achieved.
The cost of the energy required to accelerate a kilogram of payload to orbital speeds, i.e., 8 km/sec., is actually very small, on the order of 50 cents. If there were no atmosphere on Earth, payloads could be accelerated to orbital speed on Earth’s surface, using a superconducting Maglev suspension to levitate and propel the payload. The resultant total cost (energy plus facilities) to launch payloads would be extremely small, on the order of a few dollars per kilogram.
The heating and air drag forces that would occur in the presence of Earth’s atmosphere prevent such a launch system from being practical. However, if the spacecraft were accelerated in a low pressure tunnel and then launched into Earth’s atmosphere at high altitude where the atmospheric density is very low, then it would be possible to launch payloads at a very low cost.
Plus Ultra has investigated a radically new concept for magnetically levitating and accelerating spacecraft to orbital speeds and launching them at high altitudes. The Plus Ultra concept, termed StarTram, accelerates the spacecraft to 8 kilometers per second in a long (~1000 km) low pressure tunnel on the surface. After the levitated spacecraft has reached orbital speed, it transitions into an upwardly curved low pressure launch tube, along which it travels to an altitude of ~70,000 feet. The cylindrical launch tube is magnetically suspended by the magnetic repulsion forces between a set of superconducting cables attached to it, and a second set of superconducting cables, located on the surface beneath the launch tube. The two sets of superconducting cables carry oppositely directed, zero loss supercurrents.
The launch tube is stabilized vertically and laterally by a set of high tensile strength, lightweight tethers that anchor the tube to the ground, and prevent sway or movement from wind forces (Sidebar 1). The spacecraft exits through a fast opening shutter at the upper end of the launch tube into the low-density atmosphere at 70,000 feet and rapidly ascends to orbit. At the launch altitude, the atmospheric heating rate and drag forces are low enough (Sidebar 2) that the spacecraft can safely ascend into Earth orbit.
StarTram has the potential to increase the present launch volume of a few hundred tons per year to orbit to many thousands of tons per year, at a unit cost that is well below $100 per kilogram."
A big 1500 mile tube suspended with superconducting cables, floating in the air, reaching 70000ft, containing a maglev track.
http://www.startram.com/main.html
"StarTram - Ultra Low-Cost To Orbit
The current cost of launching payloads to LEO orbit is very high, on the order of $10,000 per kilogram. The launch costs to GTO and GEO are considerably greater. Major research efforts are underway on advanced reusable launch vehicles that could potentially reduce launch costs to LEO to ~$1000 per kilogram. However, the technology for these reusable vehicles is very demanding and it is not clear whether this goal can be achieved.
The cost of the energy required to accelerate a kilogram of payload to orbital speeds, i.e., 8 km/sec., is actually very small, on the order of 50 cents. If there were no atmosphere on Earth, payloads could be accelerated to orbital speed on Earth’s surface, using a superconducting Maglev suspension to levitate and propel the payload. The resultant total cost (energy plus facilities) to launch payloads would be extremely small, on the order of a few dollars per kilogram.
The heating and air drag forces that would occur in the presence of Earth’s atmosphere prevent such a launch system from being practical. However, if the spacecraft were accelerated in a low pressure tunnel and then launched into Earth’s atmosphere at high altitude where the atmospheric density is very low, then it would be possible to launch payloads at a very low cost.
Plus Ultra has investigated a radically new concept for magnetically levitating and accelerating spacecraft to orbital speeds and launching them at high altitudes. The Plus Ultra concept, termed StarTram, accelerates the spacecraft to 8 kilometers per second in a long (~1000 km) low pressure tunnel on the surface. After the levitated spacecraft has reached orbital speed, it transitions into an upwardly curved low pressure launch tube, along which it travels to an altitude of ~70,000 feet. The cylindrical launch tube is magnetically suspended by the magnetic repulsion forces between a set of superconducting cables attached to it, and a second set of superconducting cables, located on the surface beneath the launch tube. The two sets of superconducting cables carry oppositely directed, zero loss supercurrents.
The launch tube is stabilized vertically and laterally by a set of high tensile strength, lightweight tethers that anchor the tube to the ground, and prevent sway or movement from wind forces (Sidebar 1). The spacecraft exits through a fast opening shutter at the upper end of the launch tube into the low-density atmosphere at 70,000 feet and rapidly ascends to orbit. At the launch altitude, the atmospheric heating rate and drag forces are low enough (Sidebar 2) that the spacecraft can safely ascend into Earth orbit.
StarTram has the potential to increase the present launch volume of a few hundred tons per year to orbit to many thousands of tons per year, at a unit cost that is well below $100 per kilogram."
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