The $750,000 air-tight, temperature- and moisture-controlled enclosure – an unusually capable cleanroom – was completed in July and now keeps the surrounding air pristine for ISAAC, a multi-million dollar robot on a mission to build experimental composite structures.
‘Minimising foreign particles is really important when building flight hardware, but also when doing research,’ said Dawn Jegley, ISAAC project lead at NASA’s Langley Research Center in Hampton, Virginia. ‘We don’t want contaminants in the air to mess something up and mislead us in our studies.’
But ISAAC needs more than pure air from its cleanroom. The new enclosure also gives researchers the ability to control air temperature and humidity so precisely it can be used as a variable in experiments.
For instance, researchers could ask ISAAC to build a panel of composite material while holding the temperature inside the cleamroom at exactly 70°F (21°C). They could then build panels at any relative humidity level between 50–80%. Testing and inspection could then determine how those humidity levels affected the end product.
‘We don’t know anyone else who is doing that right now,’ said Brian Stewart, an engineer at NASA Langley who was part of the team that brought ISAAC to the center. ‘As a national lab, we created a capability that can do this kind of deep study and get a real understanding that we can disseminate to the composites community at large.’
ISAAC stands for Integrated Structural Assembly of Advanced Composites and it has been a part of Langley’s research arsenal since January 2015. The robot is being used to improve methods of manufacturing composite material components for use in aircraft, spacecraft, launch vehicles and other systems.
Stewart, who with Chauncey Wu and Rob Martin advocated for ISAAC in 2012, says: ‘The entire plan was to have the robotic platform as a motion base, have the heads as processing alternatives and then have the environmental capability to do this kind of stuff that we haven’t seen before.’
While a climate-controlled cleanroom was always part of their proposal, funding constraints prevented the entire system from being purchased at once. Now, Stewart says, the team’s original vision has been realised.
Getting to the finish line wasn’t always easy. Besides finding money for the project, building the cleanroom required adaptations to the lab in building that the robot calls home.
Having purchased the cleanroom’s walls and roof from a vendor, project leaders at Langley upgraded electrical service in the lab to accommodate the system’s high-powered heating, ventilation and air conditioning system and its high-efficiency particulate air (HEPA) filter.
The enclosure is 70ft by 41ft wide and 17ft high. Getting large parts and materials in and out of the cleanroom is accomplished via two retractable sections of wall and roof that allow access to the room’s interior from a ceiling crane that runs the length of the lab.
After opening the cleanroom in this way, the air filtration system is powerful enough to restore the purity level in under three hours.
On a scale of cleanliness, the enclosure will operate at ISO Class 7 – cleaner than the standard typically maintained by facilities making aircraft parts.
The system’s 20 ton climate control unit is at the heart of what Stewart described as one of the most sophisticated HVAC systems at the centre.
‘That’s because of the degree of control, the number of sensors, the pressures inside the cell, the pressures inside the system,' Stewart says.
ISAAC has been in its new cleanroom for two months and Jegley said she’s still learning from operators of other clean facilities at NASA Langley, such as the room where the SAGE-III on ISS (Stratospheric Aerosol and Gas Experiment-III on the International Space Station) instrument was held during the final stages of its development.
Extracted from an article by Sam McDonald and published with permission from NASA Langley Research Center.
