Presented at the 7th International Energy Conversion Engineering Conference, 2009.

1. Analysis and Simulations of Low Power Plasma Blasting for Processing Lunar Materials Mart í n E. Baltazar-L ó pez, Steve Best, Henry W. Brandhorst, Jr., Zachary M. Burell Space Research Institute, Auburn University, AL 36849-5320 Matthew E. Heffernan and Frank Rose Radiance Technologies, Auburn, AL, 36849

3. Introduction Chemical explosives Significant transportation cost Safety concerns Complications of Drilling and excavating on the Moon’s surface

4. Introduction Plasma Blasting is an alternative method for surface blasting Incorporates the use of electrically powered plasma blasting Allows easily adjusted explosive yield control for additional safety

6. Introduction Such a system was developed and successfully tested at the Space Research Institute (SRI) facilities Probe Inductor Capacitor 1 Capacitor 2

7. Introduction Experimental testing with plasma blasting can be expensive … and time-consuming sometimes several tests are needed in order to obtain a single valid data point

9. Objectives Apply numerical techniques to analyze and simulate the capabilities of the plasma blaster to be used in space missions.

10. Experiments with Plasma Blasting Technology Blasting test on a 24” dia. X 36” long, concrete cylinder sample (non-reinforced) with 12” probe and 52kJ pulse

11. Experiments with Plasma Blasting Technology Test setup characteristics of 24” dia. X 36” long, steel-reinforced concrete cylinder sample

12. Experiments with Plasma Blasting Technology Steel-Reinforced concrete cylinder 6.2 ft3 (0.17m3) after blast test

13. Experiments with Plasma Blasting Technology B last test shot on granite rock, with 12” Probe and 52kJ pulse

14. Numerical methods to simulate blasting Finite volume Finite difference Finite element method with explicit time integration scheme Numerical methods used to simulate the blast effects problems Hydrocodes

16. Numerical methods to simulate blasting In this work, ANSYS AUTODYN, a three dimensional hydrocode is used to simulate the plasma blasting of concrete samples with the purpose of getting an estimation of the damage of plasma blasting and then to validate those simulations with experimental results.

19. Results 2-D simulations demonstrated congruence between numerical and experimental results for blasts performed on 12’’ and 18’’ concrete cylinders

20. Results 24”x 36” cylindrical concrete sample models after 300µs simulation time of a 600MPa blast @ 60µs pulse width (a) y-plane view of 3D simulation and (b) 2D simulation

21. Results Time-history sequence of cracks and damaged zones

22. Results Cracks and damage along different radial planes after 300 µs simulation

23. Results Cracks and damage along different longitudinal planes after 300µs simulation

24. Results Damage sequence transparent view

27. Thanks