CryoTracker is a flexible probe that can provide an accurate measurement of the liquid mass in a tank. It measures both wet/dry status and temperature to take into account changes in density. Fluids that it has been tested in include liquid hydrogen, nitrogen, oxygen, methane, kerosene, and water. Custom lengths have been built up to 33 feet. CryoTracker is suitable for applications ranging from monitoring laboratory dewars through measuring propellant in launch vehicles.
CryoTracker in cryogenics testbed at NASA KSC