The combination of a regolith dryer, vapor-phase cleanup and passive condenser, and the dynamics of combining all three components into a system has never been demonstrated. Previous attempts to clean water by KSC to support ISRU were based on liquid phase cleanup and required consumables. The SBIR work by Paragon Space Development Corporation demonstrated the potential for a nafion membrane to be used as a vapor phase cleanup method, but was not tested with a realistic Mars simulant or passive condenser. The rate of vaporization, pressure drop across the nafion membrane and rate of condensation all determine the rate that water can realistically be extracted from regolith. A high fidelity Mars regolith simulant is required to evaluate the system. Regolith remediation techniques will also be investigated for removal of perchlorates/sulfates. This year's development of a small-scale breadboard could be followed up with a larger scale demonstration.More »
Sustaining human presence in space will require existing systems and vehicles to become more independent, incorporate intelligent autonomous operations, and take advantage of the local resources. Advances must be made in finding, extracting, and processing in-situ resources. This activity will address water extraction from Mars regolith. While the individual components to be used in this effort are well understood, the combination of the components into a working system has not been demonstrated. This activity will also test regolith remediation techniques for removal of perchlorates/sulfates.More »
The Mars regoilth simulant developed for this project is based on the aeolian deposit known as 'Rocknest', which was analyzed by the Curiosiy rover in Gale Crater. Rocknest is representative of the windblown drifts that occur globally on Mars. Data from Curiosity confirmed the presence of several volatiles that are released simultaneously with water as martian regolith is heated. Mojave Mars Simulant (MMS), developed at the Jet Propulsion Laboratory (JPL), was used as the main component of the simulant (96 wt. %). Perchlorate (1 wt. %) and sulfate (3 wt. %) minerals were added in laboratory tests to mimic the water release profile of Rocknest and to produce contaminating volatiles (hyrdochloric and sulfuric acids, respectively).
Nafion is a commercially available material with the unique capability of allowing water to pass through while filtering other compounds, including those found on the surface of Mars. Nafion is a Teflon based material so its chemical robustness makes it a great candidate for long term water purification. We developed a test stand to demonstrate that nafion could be used to produce purified water extracted from Mars regolith. The test stand will also allow us to collect data on the rate of water extraction as a function of several variables such as membrane surface area and regolith temperature.
The individual components used in the test stand are well understood, however, the combination of a regolith dryer, vapor-phase cleanup and passive condenser has never been demonstrated. The combination of these components drives the overall pressure and rate of water extraction. Restricting dust particles is important for this application. However, the use of an inline filter was too restrictive, and would not allow for a sufficient pressure differential across the nafion membrane. Our test stand has been modified to allow for a much larger dust filter but that configuration has not yet been tested. Some pressure transducers may be susceptible to a steam environment, even if they are rated for the temperature and pressure. This was the case with the first pressure transducers we used in our testbed. Due to complications with the test stand, we don’t have conclusive data at this time regarding water purity but this work will continue in FY18.More »
|Organizations Performing Work||Role||Type||Location|
|Johnson Space Center (JSC)||Lead Organization||NASA Center||Houston, TX|
|Human Exploration and Operations Mission Directorate (HEOMD)||NASA Mission Directorate|