An Instrumentation System for Temperature Profiling of Large Liquid Hydrogen Dewars

Liquid Hydrogen is used as a propellant for Project Rover nuclear-powered rocket engines. An instrumentation system is described which measures, records and displays vertical temperature profiles in two 50,000 gallon liquid hydrogen dewars. Platinum-resistance thermometers in each dewar are sampled sequentially. Measurements are digitized, printed, transmitted by PCM for remote recording, and reconverted to analog form for real-time graphical display. Measuring ranges are 30 to 460 degrees Rankine (OR), with 1% absolute accuracy, and 30 to 53°R, with 0.5% absolute accuracy.