Turns out a clean room doesn't necessarily need a roof, NASA is finding out as it tries out a design that could be assembled around the Orion spacecraft as it is prepared for launch in the Vehicle Assembly Building at Kennedy Space Center in Florida.
The key to the concept, developed by Astrotech, is two 10-foot-high walls of filter-equipped fans positioned 30 feet apart to push and pull the air in one direction across the capsule, keeping particles from settling on the spacecraft's surface.
A set of clear walls completes the box, but there is no ceiling. That's important because engineers want to use the large cranes already in the VAB to lift the Orion spacecraft and its shell into place as it is assembled on top of the Space Launch System rocket. If they have to build a clean room with its own crane, the cost would be much higher.