Mini-MagOrion

MMO is an interplanetary spacecraft concept, propelled by successive explosions of small nuclear assemblies (Pulse Units). The pulse units are initially subcritical, and then compressed to critical density by an imploding magnetic z-pinch. A spacecraft with this type of propulsion system could transport a 100 ton payload (crew of 4 + ground exploration equipment) to Mars in 60-90 days (one-way), and reach Jupiter in just under a year.

I was the Prinicpal Investigator for a Phase II NASA SBIR where the physics of the MMO were investigated through analysis and experiments. The program was a collaboration with Sandia National Laboratories and the University of Washington. The highlight of the program was a magnetic compression experiment on SNL's Z-Machine.

In June 2000 Andrews Space concluded a Phase I NASA SBIR on a further iteration of the Orion concept, termed MagOrion. MagOrion introduced the use of a large (2 km diameter) superconducting ring to interact with the plasma debris of the nuclear explosive pulses, replacing the mechanically dampened pusher plate of the original Project Orion concept. This enabled specific impulses above 10,000 seconds with initial system Thrust to Weight ratios from 0.2 to 10. However, the study also identified several potential showstoppers for MagOrion, such as the brittleness of current YBCO high temperature superconductors, their susceptibility to critical self-field limitations, the technical challenge of constructing a 2 km diameter superconductor in space, and the political difficulty of launching a device capable of ejecting nuclear explosives at high repetition rates. These concerns led to the next iteration in the Orion family of designs, Mini-MagOrion, which discussed here.

The Mini-MagOrion concept addresses identified short-comings of the MagOrion concept. I inherited the responsibility for the program from Andrew's Chief Technology Officer (and MMO inventor) Dana Andrews, and served as the principal investigator from January 2001-2003. The MMO design adds two important aspects to the family of Orion concepts: first, the use of magnetic compression of the fissile targets enables the utilization of much smaller explosions (50-500 GJ yield vs. 20,000 GJ), which are triggered by an external device, and thus cannot be projected as a potential weapon. Secondly, utilizing smaller yield explosions allowed for the replacement of the large superconducting ring with a more sophisticated assembly of several coils, arranged into a nozzle like configuration. The executive summary of the final program report is available in PDF format here. There is also an AIAA paper from the 2003 Joint Propulsion Conference ( PDF).

The July 2003 issue of Aerospace Engineering (published by SAE Aerospace) had the following brief article about the Mini-MagOrion program, and the pulse power experiments at Sandia National Laboratores. (Aerospace Engineering, SAEAerospace, July 2003, page 19, written by Kevin Jost)