Space Suit Testing

• NASA is designing next generation space suits, which have to undergo lots of testing before their implementation.
• To test space suits for quality, NASA uses a manikin to simulate sweat, heat, and condensation from the human body.
• Bronkhorst flow control instrumentation, such as gas flow controllers, vapor generation systems, and more, are used to simulate the human body of the manikin.

The National Aeronautics and Space Administration (NASA) recently redesigned the space suit testing system for their next generation space suits. These space suits are known as a Portable Life Support System (PLSS). In order to test the PLSS, a simulation of human metabolic load needs testing for the various subsystems. To do this, NASA simulates the human production of CO2 and water vapor along with its respective heat load.

Low Flow Instrumentation for Space Suit Testing

We work closely with NASA engineers to fully understand the application requirements. Bronkhorst instrumentation provides the accurate, stable control of water vapor that’s critical to efficient and repeatable testing; thereby aiming to nurture successful development of the PLSS.

The solution is a CEM Vapor Generation System. This system can properly control the mass of water vapor generation as well as the amount of CO2 in the vapor. NASA connects three CEM systems to an outlet manifold for their space suit testing process. Each CEM system consists of a liquid mass flow controller (H2O), a gas mass flow controller (CO2), a Controlled Evaporator Mixing device, and a readout/control unit. Together, the three CEM systems comprise the Human Metabolic Simulator (HMS).

Simulating the Human Body Using Mass Flow Controllers and Vapor Generation Systems

Control of the Bronkhorst HMS equipment is via analog (0-5 Vdc) signals through the readout/control units (1 per CEM system). In turn, they connect to NASA’s main test system, which runs their custom LabVIEW software.

This setup allows NASA to simulate aspects of human metabolic output up to a rate of ~3500 BTU/hr (over 1000 Watts). It injects the CO2/water vapor mix into a prototype of a spacesuit that contains a manikin. Furthermore, the manikin, “Manny” is wearing a Liquid Cooling and Ventilation Garment (LCVG). The LCVG removes sensible heat to keep the human core temp in nominal range. In addition, it provides some latent heat removal via condensation of human-generated water vapor on the surface of the cooling tubes.

To complete the human metabolic load simulation, NASA places controllable heaters on the CO2/H2O vapor deliver lines to prevent condensation. This also adds any super-heat as necessary. Additionally, they have controllable electric heaters on the manikin body. These heaters can simulate sensible heat generation by a human working at various levels of effort. There is also a Bronkhorst Mass Flow Controller to remove gas from the space suit testing setup. Its programming simulates metabolic consumption of suit gas as well as suit leakage.