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Capable clean room helps NASA Langley robot to build experimental composite structures

News International-French

7 Oct 2016

The $750,000 air-tight, temperature- and moisture-controlled enclosure 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.

Dawn Jegley, ISAAC project lead at NASA’s Langley Research Center in Hampton, Virginia says:

“Minimizing foreign particles is really important when building flight hardware, but also when doing research,”

“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 clean room. 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 clean room at exactly 70 degrees Fahrenheit (21 Celsius). While holding the temperature steady, they could build panels at any relative humidity level between 50 and 80 percent. Testing and inspection could then determine how those humidity levels affected the end product.

Brian Stewart, an engineer at NASA Langley who was part of the team that brought ISAAC to the center says:

“We don’t know anyone else who is doing that right now,”

“As a national lab, we created a capability that can do this kind of deep study and get a real firsthand understanding that we can disseminate to the composites community at large.”

ISAAC stands for Integrated Structural Assembly of Advanced Composites and it’s been a part of Langley’s research arsenal since January 2015. The robot is being used to improve methods of manufacturing components made of composite materials for use in aircraft, spacecraft, launch vehicles and other systems.

But the robot itself was always envisioned as one part in a suite of elements working in concert.

While a climate-controlled clean room 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 realized.

Getting to the finish line wasn’t always easy. Besides finding money for the project, building the clean room required adaptations to the laboratory in Building 1232A that the robot calls home. Having purchased the clean room’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 HEPA (high-efficiency particulate air) filter.

“A big project like this is always a challenge, but it worked out really well,” Jegley said.

The enclosure is 70 feet long, 41 feet wide and 17 feet high. Getting large parts and materials in and out of the clean room will be accomplished through 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 clean room in this way, the air filtration system is powerful enough to restore the level of purity in under three hours.

On the International Standards Organization’s scale of cleanliness, the enclosure will operate at class 7, which means it’s 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 on center. “That’s because of the degree of control, the number of sensors, the pressures inside the cell, the pressures inside the system,” he said.

ISAAC has been in its new clean room 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.

As a result, researchers working with ISAAC now use special writing paper covered in a coating that prevents it from shedding particles. Similarly, run-of-the-mill pencils aren’t allowed inside because they leave behind small amounts of carbon dust.

And despite precautions and first-rate technology, surfaces inside the clean room must be wiped down regularly. Air filter vacuums up most of the dust, but some particles will always remain.