Description: Our team proposes to define a diffusion bonding process for aluminum as an enabling step to ultimately develop an innovative, lightweight, long life, aluminum combustion chamber technology for Non-toxic NOFBXTM monopropellant In-Space 100 lbf rocket thrusters and rocket engines in general. In a companion proposal, we are investigating aluminum injectorheads: the results from these two efforts will ultimately allow us to produce an entire NOFBXTM aluminum engine. On a strict density basis, this aluminum engine would be ~30% of the mass of a nickel engine which already has a 22:1 T/W. Optimizing the design for aluminum will drive the performance even higher. This aluminum injectorhead/thrust chamber assembly will eventually be coupled to carbon-carbon nozzle assemblies. The result will be high performance, non-toxic engines with significantly increased Thrust-to-Weight Ratios approaching ~100:1. These engine assemblies can eventually be scaled up for resusable launch vehicle upper and lower stages or down into smaller in-space thrusters

Benefits: Both pure commercial entities and non-NASA government agencies are likely customers for the high performance rocket engines enabled by the proposed development. Additionally, the ability to fabricate small, lightweight structures with complex internal features without casting extends the potential reach of this technology well beyond the traditional aerospace sector into medical devices, energy, and other markets.

The NASA-related applications for devices fabricated from diffusion bonded layers of etched Aluminum foil are vast, assuming the process can be developed to provide even moderate material strength and retain a relatively high thermal conductivity. The non-toxic NOFBX-based thrusters are suitable for on-orbit position and attitude control thrusters for NASA spacecraft, and particularly suitable for Mars ascent applications. Small aluminum-based rocket motors have the potential to obtain very large thrust-to-weight ratios, which is important for small-scale Earth-based launch vehicles as well.