Propulsion may not occur in Earth's atmosphere and motors operate at high pressure. So, how can we understand combustion in that unique environment? The Combustion Lab developed a strand burner which allows observation of propellant ‘strands' at pressures up to 2000 psi in inert gas environments. Since the propellant formulation includes fuel, oxidizer, and binder, added oxygen from air is unnecessary. A High-speed camera coupled with band pass filters and lenses enable visualization of burn rates and thermographic data representative of propulsion conditions. The Combustion Lab is advancing propulsion science with new chemistry and new diagnostics that resolve fundamental processes needed to advance science.