Alexander Bolonkin

Dr. Alexander A. Bolonkin is a Russian-born (1933) scientist who moved to the United States in 1988. Numerous articles and patents.

In his book Non-Rocket Space Launch and Flight (Elsevier 2006). This is mostly a rewritten version of many conference papers. Dr. Bolonkin discusses many megastructure alternatives for space launch, from the space elevator to dynamic structures to gas guns to electrostatic devices. Dr. Bolonkin presents many ideas, with some analysis, and focuses on what might work, not on what might go wrong, avoiding the sort of analysis engineers do before deployment (it is cheaper to break stuff and find fixes with math before cutting metal, especially for megastructures).

Launch Loop uses magnetic fields and vacuum confinement. Non-Rocket... has two chapters on Kinetic Space Towers (Chapter 5, IAC-02-IAA.1.3.03 2002, JBIS 57 1/2, 2004, pp 33-39) and on Kinetic Anti-gravitator (Chapter 9, IAC-02-IAA.1.3.03 2002, AIAA-2005-4504). These are open, vertical systems, and use outer rollers for turnarounds. Dr. Bolonkin does not discuss how these rollers are made, or how a roller can rotate with high edge speed without flying apart. The launch loop elevators include tapered high-velocity pulley rollers moving at 400 meters per second, and this is probably too optimistic.

Dr. Bolonkin may be unaware of the effects of gravity on vertically moving cable velocity. The launch loop cable is moving at 14000 meters per second at 80 kilometers altitude. As it descends towards the surface, it picks up speed, adding an additional 9.7 x 80000 Joules per kilogram, raising the speed of the cable to 14055 meters per second. Since the mass flow rate is constant at 42000 kilograms per second throughout the system, this means that the density of 3 kilograms per meter at 80 kilometers altitude must be reduced to 2.988 kg/m at the surface - a 0.4 percent stretch. Payload launching results in both stretching and compression, again because of velocity changes.

Dr. Bolonkin's towers are similar heights (75km) and run at lower velocities ( 8000 m/s ) so the stretching must be larger. If the velocity is 8000 m/s at the top, the velocity at the bottom must be 8090 m/s, a stretch of 1.1 percent. If the cable is solid and made of a strong material, that stretch is associated with tensile stress at the bottom, which adds to the compression burden on the tower. If there is no tension at the bottom, then the cable at the top will meander, like a rope pushed from both ends.

This is why the launch loop rotor (like Bolonkin's cable ) has sliding joints, which resist lateral bending but otherwise offer only slight resistance to longitudinal stress, allowing the rotor to change longitudinal density. Most of the material in the rotor is iron, perhaps with some insulation ot direct eddy currents. A solid iron rotor, and most insulator materials, will fracture if subjected to strains approaching a percent.

On page 184 of Non-Rocket..., Dr. Bolonkin briefly mentions the launch loop, quoted below:


In 2002 Loftstrom4 published a description of a space launcher. The offered device has the following technical and physical differences from the Loftstrom installation.

The Loftstrom installation has a 2000-km long launch path located at an altitude of 80 km, which accelerates the space vehicle to space speed. The Loftstrom space launcher is non-connected plates of complex path enclosed in an immobile tube. The plates are made from rubber-iron material and is moved using an electromagnetic linear engine. The plates are turned by electromagnets.

The idea offered in this chapter is the kinetic device which creates a push (repulsive, repel) force between two given bodies (for example, between a planet and the apparatus). This force supports a body at a given altitude. The body is connected to the cable by rollers that slide along the cable. The cable can be made of artificial fiber and moved by the rollers and any engine. The kinetic anti-gravitator supports any body at altitude (for example, towers) and may also be used to launch vehicles. The Loftstrom device is only a space launcher and cannot permanently support a body at altitude or towers (he did not write anything about this).

4. K.H. Lofstrom, "The Launch Loop: A Low Cost Earth-to-High-Orbit Launch System", 2002, http://www.Launchloop.com/launchloop.pdf


Dr. Bolonkin is referring to a 2002 paper for the International Space Development Conference. Launch loop was first published in November 1981 in the American Astronautical Society Reader's Forum. With much of the activity concerning launch loop published before his arrival in the west in 1988, and the references in the 2002 paper perhaps difficult for a native Russian speaker to parse, perhaps he does not understand that this is a much older idea.

The description of the rotor is plainly incorrect. There is no rubber in a launch loop. With the rotor core heating up to 600C, rubber would not survive. The "plates" (actually tubes) are connected with sliding joints in order to accomodate stretch. The launch loop does include "towers" - west and east stations are large 5000 ton stationary platforms at the top of cables, supported by the 8 degree deflection forces of the east-bound and west-bound rotors.

There is not high friction at the ground in a launch loop. Bolonkin exposes his moving cables to atmosphere, resulting in high turbulent drag (and yes, it will be turbulent, the unguided cable will vibrate laterally and stir the air). The launch loop assumes that the rotor is continuously guided by actively controlled electromagnets inside a tubular vacuum sheath. Active guidance is necessary to keep the spacings small, especially where the rotor approaches the main deflection magnets. A lot of electronics is needed. Fortunately, we know how to make a lot of electronics, cheaply and reliably. The electronics power, responsible only for correcting lateral vibration, is a tiny fraction of the drag power of a high-speed cable in air. If the double-walled launch loop sheath is breached, air will flow in and cause drag, lots of it. Internal air will be pulled by the moving rotor to the next vacuum pump station. The section subjected to air drag will be short, Hopefully, the breach will be patched quickly.

While the launch loop paper does not describe the use of the technology for towers only, this is not an oversight. To provide the lift force, the launch loop stores an enormous amount of energy and momentum, and that momentum is directed horizontally for part of the rotor's path. When (not if) the launch loop breaks, some rotor material will be flung horizontally, acting like hypervelocity penetrators. This is incredibly dangerous. The nearest vulnerable target (besides the launch loop itself) should be hundreds of kilometers away, allowing the rotor sections to disintegrate and the fragments to slow down to safe speeds. Launch loop technology should not be used near large populations, and is best deployed at sea. It is also most easily deployed from a flat surface, and the ocean approximates that.

With a cheap space launcher, altitude is best achieved by launching something into orbit.