"The future is not a result of choices among alternative paths offered by the present, but a place that is created. Created first in mind and will, created next in activity. The future is not someplace we are going to but one we are creating. The paths to it are not found but made, and the activity of making them changes both the maker and the destination."
John Schaar
As the commercial launch market continues to grow, it will soon become worthwhile to take the next step towards Affordable-to-the-Individual space flight -- the building of the Earth Orbiting Elevator. The Earth Orbiting Elevator concept shown here is based in part on the elevator-into-space idea that was described by Arthur C. Clark in his book, The Fountains of Paradise. That particular space transportation concept consisted of hanging a cable from geostationary orbit down to the Earth's surface and moving people and freight from Earth into space on an elevator that would ascend and descend along the cable. Unfortunately, it is an idea that cannot be built with existing materials.
Skyhook Gateway is an intermediate version of that idea that can be built with existing materials. The concept works by starting from a much lower altitude orbit and hanging the cable down to just above the Earth's atmosphere. The length of the lower half of the cable is selected such that the Spaceplane can deliver a payload to the bottom of the cable without the need for an expendable upper stage. This increases the useful payload of the Spaceplane from 17,500 pounds per flight, to over 40,000 pounds per flight, while eliminating the cost of the upper stage.
This reduces the user cost to Earth orbit from $1200 per pound to $550 per pound to the cable Midpoint Station (at a flight rate of 72 flights per year). This cost reduction will undoubtedly have a major impact on making commercial space operations affordable and profitable for an increasing number of products and as a result further increases the demand for launch services. As before, this cost estimate includes the amortization of the initial investment (for both the Spaceplane and the Earth Orbiting Elevator), all recurring costs (Spaceplane and the Earth Orbiting Elevator), and profit for both.
In addition to acting as a balance to the lower half of the cable, the upper half of the cable can also be used to boost satellites and spacecraft into higher orbits. In order to take maximum advantage of this ability, the length of the upper half of the cable is made so that it's endpoint is traveling at just slightly less then escape velocity for its altitude. This is done so that when a satellite bound for geostationary orbit is released from the upper end of the Earth Orbiting Elevator, it can be placed in a geosynchronous transfer orbit with only minimal use of its onboard propellant.
While the total weight of the initial Earth Orbiting Elevator is quite a bit more then today's satellites and spacecraft, a complete ready-to-operate system could be placed in low Earth orbit with only 4 Energia launches.
The markets for this combination Spaceplane, Personnel Launch Vehicle, and Earth Orbiting Elevator space transportation system are;
- the launching of commercial satellites into any Earth orbit,
- Space Station re-supply,
- Space Station crew-exchange,
- on-orbit assembly, checkout, re-supply and servicing of orbiting commercial man-tended factories,
- on-orbit assembly, checkout and servicing of satellites,
- the boosting of satellites and spacecraft bound for the Moon and beyond to escape velocity.