Possibilities of Lorentz Electromagnetic Accelerators (LEA) for launch of Payloads in Low-Earth-Orbit (LEO)

Paper number

IAC-08.C4.6.6

Author

Dr. Ognjan Bozic, German Aerospace Center, Germany

Year

2008

Abstract

In the recent time, due the need to launch more payloads in Earth orbit, raise the interest of space industry for investigation and development of new electromagnetic accelerators (LEA). With such kind of launch-assist technology, the transport of payloads to Earth orbit could be cheaper and accessible. The advantage of LEA systems which contains catapults or tube launchers installed on Earth surface is the capability to transmit direct kinetic energy at launch packages. While the possibility of such accelerators are insufficient or impracticable for direct launch of payloads into space, they should be combined with small rocket launchers or rocket space planes to achieve the goal. In combination with a launch-assist due to LEA the rocket launcher or space plane should have considerable lower construction mass and propellant consumption. Simultaneously the whole ground based launch-assist system could be used for large number of starts, allowing to keep low the launch costs (re-usability aspect).

Among a number of possible electromagnetic accelerator systems, due high efficiency three systems attracts the attention of investigators: superconducting Maglev/Maglifter transport system, coil accelerator and rail accelerator (known in tube design as railgun). In more studies and some surface tests (NASA, US Navy, some universities and Space Tram Inc.,UK) are envisaged the Maglifter concept (based on linear induction motor – LIM) for start of heavy payloads measured in Mg with subsonic velocities up 200m/s at about 1G. Maglifter launch-assist is investigated for aircraft like operations rocket space-planes with horizontal takeoff. For LEO start of launch packages with weight in the range between 300kg and 3000kg a suitable solution could be coil accelerator. Coil accelerator operates also as LIM. It consists of series of solenoidal coils which are energized at appropriate time by a computer-triggered switches and capacitors. When the coil is energized with the armature inside it, the rising magnetic field induces a circular current in the armature. The interaction of armature current with the radial component of the coil magnetic field drives the armature and launches the package forward. The important feature of coil accelerators are high total and electric efficiency, low maintiance and long life time. Rail accelerator technology has reached a maturity level that makes it a potential candidate for the launch of small payloads (i.e. nano- and micro-satellites) in LEO. For such systems it could be expected high performances concerning velocity, efficiency, launch costs and repetition rate.

The paper presents and discusses the state of the art of the three above mentioned most promising EA systems, they properties are compared and commented. Also are commented the possibilities and limitations of these systems by near future potential applications. To illustrate the possibilities of a rail accelerators one concept for launching of nano-satellites into LEO analyzed by the German Aerospace Center (DLR) – Institute for Aerodynamics and Flow Technology is described in detail.

Abstract document

IAC-08.C4.6.6.pdf

Manuscript document

IAC-08.C4.6.6.pdf (🔒 authorized access only).

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