StarTram: The Magnetic Launch Path to Very Low Cost, Very High Volume Launch to Space

Abstract

Rocket based Earth to space launch systems are limited to a few hundred tons of payload annually at $~10,000 per kilogram. Over the past 30 years only marginal cost reductions have been achieved. Electromagnetic launch to space can greatly reduce launch cost and increase launch volume. StarTram uses superconducting maglev to accelerate heavy payloads ~20 to 30 tons, to orbital speed, ~8 kms/sec, in evacuated tunnels at ground level. Superconducting 20 ton Maglev passenger vehicles using the 1966 inventions of Powell and Danby now operate in Japan at 360 mph in the open atmosphere limited only by air drag. In evacuated tunnels, orbital speeds are possible. Two StarTram systems are described. The near term Gen-1 system launches 35 ton cargo craft from the surface at a high altitude location, e.g., ~4000 meters. The cargo craft ascends to orbit, where a small delta V rocket burn establishes orbit. Launch energy cost is only ~$0.50 per kilogram of payload. Adding costs of the cargo craft, operating personnel, and the amortized launch facility, total launch cost is only ~$50 per kg, compared to $10,000 per kg using rockets. A single Gen-1 facility can launch over 100,000 tons per year to orbit, 500 times current world capacity. Applications for the Gen-1 system includes greatly expanded Earth monitoring and communications, national defense, beamed power to Earth and robust space exploration. The Gen-1 system is described including Maglev levitation and propulsion, superconducting energy storage, the exit into the atmosphere, and the cargo craft design. Also described are the aerodynamic heating and deceleration forces on the cargo craft as it ascends to orbit. The initial deceleration is ~10 g and nose heating rate is ~20 kW/cm2. Both decrease to zero in a few seconds. Delta V loss through the atmosphere is about 500 meters/sec. Technology for the Gen-1 systems already exists and a Gen-1 facility could operate within 10 years. The U.S., Russia, China and Europe each have the technical capability and suitable high-altitude sites for a Gen-1 system. Potential sites are described. The Gen-2 StarTram system to launch both cargo and passengers is also described. It is a longer term, and requires a magnetically levitated launch tube to reach high altitude.