Topic

OUSD (R&E) MODERNIZATION PRIORITY: Autonomy TECHNOLOGY AREA(S): Space Platform The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws. Please direct questions to the Air Force SBIR/STTR HelpDesk: usaf.team@afsbirsttr.us. OBJECTIVE: Develop and commercialize self-regulating (positive temperature coefficient, PTC) heaters for use on satellites in any earth orbit. DESCRIPTION: Self-regulating heaters are heaters with a designed-in temperature setpoint that exists as a property of the resistor material. They are ‘smart’ heaters, automatically and independently warming each region of the heater circuit to the designed setpoint without a temperature sensor. The electrical resistance of the heater material jumps substantially at the setpoint, inhibiting electric flow and production of heat above the setpoint temperature. Self-regulating heaters are in use in the petrochemical and automotive industries for pipe freeze protection and seat warmers. The space industry needs self-regulating heaters for propellant system heaters where allowable temperature ranges are tight and thermal environments vary in both time and space. Conventional solutions to propellant system thermal control are resource intensive, requiring much engineering design and touch labor as well as much hardware and burdening the flight computer to control the circuits. Self-regulating heaters reduce all of these resource demands. Self-regulating heaters can also provide similar benefits for other satellite heaters such as those for batteries, mechanisms, and antennas. Existing self-regulating heaters are not suited for space applications for several reasons: 1) the form factor is too large and inflexible: existing self-regulating heaters are a stiff cable while satellite self-regulating heaters must be a thin-film heater such as adhesively-applied polyimide heaters commonly used on satellites. Additionally, these heaters must be suitable to install on two orthogonal bend axes: a 1/8” bend radius and a 3” bend radius, 2) existing self-regulating heaters provide their resistance transition via a melt expansion process to break the percolating path; this means that existing self-regulating heaters cannot be exposed to temperatures greater than their setpoint temperature, 3) Existing self-regulating heaters are not designed to handle the space environment; specifically: vacuum, ionizing radiation, and wide thermal cycles. This topic solicits proposals to develop and commercialize self-regulating heaters for space applications that address these aforementioned insufficiencies of existing self-regulating heaters. Additionally, the materials design must be capable of tuning during manufacturing of the material for setpoint temperatures between -5 and 20 C. A 30:1 (threshold) and 100:1 (objective) turndown ratio between the electrical resistances above and below the setpoint temperature must be achieved. The technology must be capable of yielding designs operating with any voltage between 12 and 100 VDC, and must be capable of producing designs yielding 1 to 10 W/in2 heat flux at the fully ON condition. Capable to withstand exposure to environments in all of the following orbits: 5 years in low earth orbit (LEO), 10 years in middle earth orbit (MEO), or 15 years in geosynchronous earth orbit (GEO) including vacuum, ionizing radiation, and thermal cycling. Radiation environments should assume the technology receives 40 mils of spacecraft Aluminum shielding (threshold) or no additional shielding (objective); radiation shields incorporated in the heater will be considered but radiation-hardened heater materials are strongly preferred. Thermal cycles between -5 and 40 C, with LEO 60k cycles, MEO 15k cycles, and GEO 6k cycles. Also survive up to 10 thermal cycles from -40 to 70 C. The material should always remain a solid. The manufacturing process should be scalable, e.g. screen printing techniques; the installation process should minimize touch labor. Proposers must demonstrate a strong intent and capability to commercialize the technology. Proposers are strongly encouraged to form teams with manufacturing partners and systems integrators for technology transition. PHASE I: Build and test the performance of hardware. Demonstrate by analysis and/or test the feasibility of the concept to meet all requirements. PHASE II: Further develop manufacturability of hardware. Test environmental capability of the hardware. The culmination of the Phase II effort shall include the hardware delivery of 10 functional, tested self-regulating heaters demonstrating a variety of sizes and mounting configurations. PHASE III DUAL USE APPLICATIONS: Design, build, deliver, and support an experiment to allow the USSF to demonstrate the technology in a combined effects environment. REFERENCES: Gilmore, D. G., Spacecraft Thermal Control Handbook Volume I: Fundamental Technologies, 2nd Ed, The Aerospace Press, El Segundo, CA, 2002; Wertz, J.R., Larson, W.J., Space Mission Analysis and Design, Microcosm Inc. Hawthorne, CA, 10th Ed, 2008; Fortescue, P., Stark, J., Swinerd, G., Spacecraft Systems Engineering, 3rd Ed., John Wiley and Sons, West Sussex, England, 2003. KEYWORDS: Resilience; Directed Energy Threat; DE threat; hardware