Molecular Adsorber Coating (MAC)

The NASA life support system uses a regenerable vacuum swing adsorption process, known as Sorbent-Based Air Revitalization (SBAR), to separate water and carbon dioxide for disposal. The SBAR system is an adsorbent-based swing bed system that has been optimized to provide both humidity and carbon dioxide control for a spacecraft cabin atmosphere. The system comprises composite silica gel and zeolite-packed beds for adsorption and a bypass system for flow control. Under normal operating conditions, the disposal system would require a high-quality vacuum environment to operate. Improvements to the SBAR system include an enhanced inherent capacitance that extends the operation time within a non-vacuum environment for up to 4.5 hours. Flight time can be further expanded with multiple SBAR systems to allow for system regeneration. By scheduling periodic thermal regenerations&#151nominally during sleep periods&#151the SBAR technology may be suitable for missions of unlimited duration.

Storage and transfer of fluid commodities such as oxygen, hydrogen, natural gas, nitrogen, argon, etc. is an absolute necessity in virtually every industry on Earth. These fluids are typically contained in one of two ways; as low pressure, cryogenic liquids, or as a high pressure gases. Energy storage is not useful unless the energy can be practically obtained ("un-stored") as needed. Here the goal is to store as many fluid molecules as possible in the smallest, lightest weight volume possible; and to supply ("un-store") those molecules on demand as needed in the end-use application. The CFC concept addresses this dual storage/usage problem with an elegant charging/discharging design approach. The CFC's packaging is ingeniously designed, tightly packing aerogel composite materials within a container allows for a greater amount of storage media to be packed densely and strategically. An integrated conductive membrane also acts as a highly effective heat exchanger that easily distributes heat through the entire container to discharge the CFC quickly, it can also be interfaced to a cooling source for convenient system charging; this feature also allows the fluid to easily saturate the container for fast charging. Additionally, the unit can be charged either with cryogenic liquid or from an ambient temperature gas supply, depending on the desired manner of refrigeration. Finally, the heater integration system offers two promising methods, both of which have been fabricated and tested, to evenly distribute heat throughout the entire core, both axially and radially. NASA engineers also applied the CFC to a Cryogenic Oxygen Storage Module to store oxygen in solid-state form and deliver it as a gas to an end-use environmental control and/or life support system. The Module can scrub out nuisance or containment gases such as carbon dioxide and/or water vapor in conjunction with supplying oxygen, forming a synergistic system when used in a closed-loop application. The combination of these capabilities to work simultaneously may allow for reduced system volume, mass, complexity, and cost of a breathing device.

The following methods can be used individually or in combination to generate superhydrophobic surfaces: Synthesis of novel copolyimide oxetanes with unique surface properties The technology is the synthesis of a polyimide coating or film with a modified surface chemistry shown in Figure 1. A minor amount of an oxetane reactant containing fluorine is added to the polyimide, and the oxetane preferentially migrates to the surface, enabling relatively high concentrations of fluorine at the surface, without compromising the functional performance of the bulk of the polymide coating/film. The copolymers exhibit mitigation of particle adhesion and fouling from exposure to various particulate and biological contaminants and exhibit reduced surface energy and increased surface fluorine content at extremely low oxetane loadings relative to the imide matrix (see Figure 2). Additionally, the short fluorinated carbon chains do not bioaccumulate, reducing the environmental impact of these materials. Modifying surface energy via laser ablative surface patterning This method uses a laser to create nanoscale patterns in the surface of a material to increase the hydrophobicity of the surface (see Figure 2). The benefits of hydrophobic surfaces include decreases in friction and increases in self-cleaning properties. This is an advantageous method of surface modification because it is fast and single-step, promises to be scalable, requires no chemicals, could be applied to a variety of materials, and does not require a planar surface for patterning.

This NASA innovation applies the concepts of electrodynamic dust shielding (EDS) to develop seals (e.g., O-rings) with active self-cleaning capabilities. NASA’s self-cleaning seals are manufactured in the following manner: A seal with a conductive surface (or otherwise fabricated to be conductive) is generated and an electrical connection, lead or electrode is attached. Next, a dielectric material is coated or placed over the conductive surface of the seal. (NOTE: Using conductive elastomer materials eliminates the need for a conductive cover layer) A high voltage (nominally >1kV) power supply is connected to the conductive layer on the seal and grounded to the metallic groove or gland that houses the seal. Given the design, dust accumulates on the outer dielectric layer (a high-voltage insulator) of the seal. To clean the seal, a time varying alternating voltage is applied from the power supply, through the high voltage lead and onto the conductive layer of the seal. When this voltage is applied, the resulting electric field produces Coulomb and dielectrophoretic forces that cause the dust to be repelled from the sealing surface. In practice, NASA’s self-cleaning seals could be operated in continuous cleaning mode (actively repelling dust at all times, preventing it from ever contacting the seal surface) or in a periodic cleaning cycle mode (removing dust from the seal surface at regular intervals). NASA’s self-cleaning seals have been prototyped and demonstrated to be highly effective at dust removal. The invention could serve as the basis of an active, self-cleaning seal product line marketed for in-space and/or terrestrial applications. Additionally, companies developing space assets destined for operation on dusty planetary surfaces (e.g., the Moon) may be interested in leveraging the technology to protect seals from dust/regolith accumulation, ensuring continuous low leakage operations.

In addition to previous LOTUS coating formulations, an additional optical formulation may be applied via vacuum deposition. This coating forms a top layer and may be applied in different thicknesses that serve to enhance its hydrophobic properties. The vacuum deposited material may comprise fluorinated ethylene propylene or a similar material. This coating is transparent and can be used on optical components or any other applications requiring a clear coating.