There is a design for a new new space launch system that would leverage an inflatable tower design.
Fisher Space Systems LLC has created the design for an inflated tower combined with a rotating system that will fling a reusable launch vehicle to space. It will only need a reusable upper stage. It could also be combined with a rotovator for the upper stage. Electricity can power the elevator ride up and power the rotating system.
The Space Track Launch System (STLS) is a two stage system. The first stage is a tall tower 100-150 km high. An electrically driven rotating truss at the top of the tower is attached to two sets of ribbons made of high strength fiber composites. Counterweights (CW) are attached to the end of each ribbon. The second stage is a reusable liquid fueled launch vehicle (LV) designed to launch form the STLS.
The system is unique for several reasons. First, the first stage is all electric and can be used up to three times a day. The electric motors restore rotational kinetic energy to the ribbons in approximately 8 hours. Second, the launch vehicle launches from a point along the ribbon as opposed to being released from the end of the ribbon. For a 30 ton launch vehicle, launching from the end of the ribbon produces a compressive shock wave that will destroy the ribbon and damage the tower. When launched from the middle of the ribbon, the additional force on the ribbon is several orders of magnitude less than the tension in the ribbon. As such, the impulse from launch is absorbed by the ribbon and counterweights and the stress on the tower is greatly reduced. Finally, the materials are presently available to build a first generation system capable of placing 400 kg of payload into a low earth orbit up to three times a day.
There are many SkyScreamer rides in Six Flag parks. The tallest are about 120 meters tall
With two sets of ribbons, two second stage launch vehicles can be launched for each recharge cycle resulting in eight to ten launches or approximately 24,000 to 30,000 kg of mass into low earth orbit per week. The over carriage can accommodate a wide variety of launch vehicles making the Space Track Launch
System an economical and universal launch system.
For a carbon nanotube ribbon, the launch point for a 6g acceleration is 119 km, the launch velocity is 2.5 km/s, the altitude of launch is approximately 130 km.
The orbital velocity at 150 km is approximately 7,875 m/s. For a launch velocity of 2,899 m/s (which includes Earth’s contribution), the Δv is 4,977 m/s. For a specific impulse of 330 sec the mass of propellant required to achieve orbit is about 3.6 times the mass at main engine cutoff. For a gross liftoff mass of 80 ton, the mass at main engine cutoff is approximately 17.3 tons. This mass consist of the payload mass, inert mass of the launch vehicle which includes integral propellant tanks, and all remaining propellants necessary to achieve a stable orbit, for orbital maneuvering, and retro fire to return to Earth.
The mass of the launch vehicle at main engine cutoff can be assumed to be approximately 11 times the payload mass. Using 17.3 tons as the launch vehicle mass at main engine cutoff gives a payload mass of approximately 1,500 kg. This is cargo to an orbiting space station or about 5 passengers to an orbiting space station
A first generation system, built with present day materials (Spectra 2000), can launch two 20 ton launch vehicles 144 seconds apart and put approximately 720 kg of payload into a low earth orbit every thirty hours. Stronger materials under development today will lead to future generation systems with enhanced capabilities.
The proof of concept system will be a 25 km tall sub-scale model of a fully operational first generation system. The proof of concept system will demonstrate the viability of an all electric first stage launch system. It will demonstrate the launch of a second stage suborbital launch vehicle with separation from an overcarriage and the mitigation of the shock wave in the ribbon produced during launch.
The proof of concept system will demonstrate torque buffering while restoring rotational kinetic energy and demonstrate gyroscopic and pressure stabilization of the unbalanced force. Finally, the proof of concept system will demonstrate the viability of using inflated multi-beams for heavy load bearing structures in the tall towers of the Space Track Launch System.
Inflatable tower 20-200 kilometers tall being developed by other researchers
The full paper for the feasibility of the 20 km inflatable tower is here. The inflatable tower is being worked upon by other researchers.
They have written follow up papers on their experimental work with scaled inflatable systems.
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
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