Sierra Nevada Corporation is one of the private sector companies trying to help NASA get back to the moon. The company is developing what it calls the 'Large Inflatable Fabric Environment" at the Johnson Space Center in Houston, Texas. Sierra Nevada hopes NASA will use the habitat in its new Artemis program, which will lead the U.S. back to the moon and, eventually, Mars. Sierra Nevada's habitat is competing with prototypes from Boeing, Northrop Grumman, and Bigelow Aerospace — plus a concept from NanoRacks. NASA began testing the prototypes on the ground in March. The space agency says those tests should last several months.