Friday, August 28, 2009

ALICE details

I extracted some tidbits from:
Tyler D. Wood, Mark A. Pfeil, Timothee L. Pourpoint, John Tsohas, and Steven F. Son of Purdue University and T.L. Connell, Jr, Grant A. Risha and Richard A. Yetter The Pennsylvania State University, "Feasibility Study and Demonstration of an Aluminum and Ice Solid Propellant", 45th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, AIAA 2009-4890, August 2009.

This preceded the actual flight test. There is a chance I've misrepresented a fact...this is just a blog...
  • Aluminum and water propellants are not a new idea but have been rendered feasible by the availability of nano-scale Al (nAl) powder.
  • The theoretical vacuum ISP is over 300s.
  • The nAl naturally reacts with water and such propellants have a limited shelf life. Alumina coated particles help.
  • Keeping the mix at sub-freezing temperatures expends the useful life to 40 days - hence Al-ice or ALICE.
  • They used a resonating mixer.
  • The flight motor propellant (from static test):
    • ISP=160
    • one 3" dia. x 6.75" long grain, with 1" core
    • 1285 N-s (a baby 'K')
    • 1650 psi
    • peak thrust ~2500 N
    • ~ 1 second burn
  • The motor:
    • 4" dia.
    • custom turned aluminum to allow over 3k psi
    • a very long head-end igniter (despite the nAl particles, it needed a lot of energy to get it going)
  • The rocket:
    • a carbon fiber Mongoose (as I previously guessed) built with standard HPR techniques
    • they used dual R-DAS altimeters
    • the tested in on an Aerotech K780R
    • the references indicate they used RockSim 8
I find this fascinating and hope you hear about their continuing work to improve the propellant. It's cool that sport rocketry products are being used to support serious research.