North America's #1 selling thermal mass flow meter offering (Flow Research, Yoder), our heavy-industrial thermal mass flow meters are designed for the most demanding industrial gas mass or air flow measurement applications. Early developments in the evolution of mass flow meters in the 1950’s were largely driven by the need for highly accurate gas mass flow readings. Over the last 50 years the demand for substantially higher flow measurement precision has only intensified. For the last 25 years, NASA has relied on the accuracy of Sierra thermal mass flow meters to get the right mixture of nitrogen, argon and oxygen to their shuttles during ground testing. Six years ago, Sierra expert, Steve Chism, identified a way NASA could upgrade the outdated technology they were using to maintain positive space shuttle cargo door air flow on re-entry. He was convinced that Sierra’s Model 780S thermal mass flow meter was ideal for this mission-critical function. Compact, no moving parts, accurate and easy to move from shuttle to shuttle, NASA agreed to give the 780S a try and was immediately delighted with its performance.  Extremely stable patented Dry-Sense technology combined with Field Validation and a lifetime sensor warranty gave NASA engineers a perfect mass flow measurement tool.  To prove the accuracy for this mission critical shuttle cargo door application, Sierra hired CEESI, a world renowned 3rd party calibration consultant in Colorado, to conduct an in-depth field test. CEESI determined conclusively that Sierra’s meters performed well within specifications. Watch the Video...