267 flow out of the hopper and into the auger lift mechanism. The Tephra was also successfully withdrawn  from the reactor with gravity feed through the out let valve. The valves performed well but required  adjustment in order to achieve the desired leak ra te without having excessive torque on the actuation  mechanism.   Multiple reactor operations were performed. The goal  was to process three batches with one of the two  reactors performing back-to-back tests. The ISRU tests were performed successfully and it was shown that water could indeed be made from Tephra and subsequently electrolyzed to produce oxygen.   Severe dust storms and fluctuating temperatures  added to the challenges of the field test and  emphasized the fact that the equipment design must  be very robust to survive the environmental  conditions it will face on the moon which will be much  more severe than anything that can be experienced  in a field test on Earth.  There were several lessons learned during the desi gn phase, assembly and integration phase of the  Roxygen I system, and also during the field testing on Mauna Kea.    The design team was geographically dispersed between Florida, Texas, Ohio, California and New Jersey. Collaborative work was required using Computer Aide d Design (CAD) tools and electronic data exchange  as well as more traditional methods such as team telecons and white board brainstorming and design sessions. Communication through weekly telecons wi th frequent CAD file exchange was vital to making  this team function effectively.    Lead times for regolith tolerant valves with metal seals were a challenging aspect of this design. Regolith  valves are highly specialized and few vendors were capable or willing to tackle this challenge. Lead times as long as 6- 8 months for a custom valve design ar e typical. The motors on top of the auger tubes were  not aesthetically pleasing and increased the volumetr ic envelope of the ROxygen 1 system substantially.  Other designs were subsequently developed during the Phase I concept generation, and the system  involving pneumatic conveying of regolith was event ually selected as the regolith feed system for  ROxygen II.  During the assembly and integration phase of ROxy gen I, the input hopper system was built in a mock up  version using polycarbonate sheets for flow visualization. The flow was immediately visible and verifiable. Many hours of analysis were saved by rapid prototyp ing and experimental testing methods. In addition,  an opportunistic reduced gravity flight on the C-9 NASA aircraft at Ellington field proved that the concept  would work under 1/6-g conditions using gravity feed albeit with some enhancements to accelerate flow.     It was also discovered that the auger worked well wi th JSC-1a in the vertical configuration but was  inconsistent with Tephra in that orientation. As a result, it was found during the checkout stage of the Mauna Kea field test that the auger system could work  reliably with Tephra at an incline angle of 10 deg  from the vertical. The auger system is sensitive to particle size and type. Large pebbles tended to jam the  auger, so that a size sorting system is needed for auger-based regolith feeding systems. This was  achieved during the field test by pre-sieving and final  sieving using a mesh screen mounted on the auger  opening.  In addition to the Mauna Kea field test, a 2008 reduced gravity flight experiment was performed to study  the effect of gravity on the flow of regolith was st udied onboard a reduced gravity flight using a mock-up  of the ROxygen I hopper (see Fig. 5). The lunar regolith simulants studied were NU-LHT-2M, JSC-1A, and OB-1, and the experiments were conduct ed at 1/6-g, 1/3-g, 1-g, and 2-g.   NASA/CP-2010-216272