technology opportunity the is disposed of into the ocean) can be more costly, costly, more be can ocean) the into of which disposed is (in re-entry spacecraft the controlled Because possible. to atmosphere re-entry Earth’s uncontrolled make helps assembly RWA Goddard’s large orbits. and other small in for option spacecraft good a simple, it The makes also missions. design (LEO) orbit modular Earth low atmos- for Earth’s ideal to it re-entry making upon phere, (demise) up is that burn or (RWA) melt to assembly wheel designed reaction patent-pending new, its license Center Flight Space Goddard NASA www..gov N only reaction wheel of its size to facilitate the option of uncontrolled uncontrolled of option the re-entry. facilitate to and size first its of the is wheel RWA reaction demiseable only The in left ocean. the itself) into spacecraft deposited or the of orbit remains (the It debris option. reduces attractive greatly an is also re-entry uncontrolled risky, and complex, A Demiseable Reaction Wheel Assembly Wheel Reaction Demiseable A e c a p s o r e a ational Aeronautics andSpaceAdministration ...lowering the cost, complexity, and risk of uncontrolled re-entry for LEO missions LEO for re-entry uncontrolled of risk and complexity, cost, the ...lowering invites companies to to companies invites

• Benefits • • • •

required of controlled re-entrycontrolled requiredof planning mission additional and fuel, extra systems, propulsion special for need the Removes missions space Simplified possible re-entry demiseable trolled, uncon making by missions LEO for re-entry of risk the risk Low demise complete enabling efficient, very heat to exposure makes that tecture archi an with temperatures low relatively at melt that Innovative spacecraft of sizes all on tions applica specific to tailored be to RWA the allow Nm 0.5 to up torque and Nms 80 to 10 from Scalable designs traditional with compared as balancing and assembly simpler and costs manufacturing reduced complexity,for providing design Modular : Helps to lower to Helps : : storage Momentum : : Combines materials Combines : : Offers reducedOffers : : - - - Technology Details How it works predictably, eliminating the option of uncon- trolled re-entry. In contrast, Goddard’s RWA Applications Goddard’s demiseable RWA combines material choices, part design, and layout that make the uses materials, part design, and layout that expe- The demiseable RWA facilitates design completely demiseable, aiding uncon- dite and ensure complete demise. Uncontrolled for small- to trolled re-entries. The technology features new re-entry is an important goal for many LEO large-size spacecraft for: designs for the flywheel and motor stator. missions and may play a larger role in mission planning in the future. ∑ LEO missions Constructed of aluminum, the flywheel has a low melting temperature, aiding in faster Goddard’s RWA is designed from a systems per- ∑ GEO missions demise of the entire assembly. In addition, the spective to limit the size, complexity, and cost ∑ Lunar and Martian missions stator contains very little iron, which melts at a involved in LEO missions. Its low-power design higher temperature. puts less strain on the spacecraft power systems. In addition to employing highly demiseable Solar panels and batteries can be smaller and materials, the design of the RWA itself also lighter, thus reducing overall spacecraft size and facilitates maximum demise efficiency and mass. In addition, the cantilevered flywheel predictability. Rounded cutouts in the web, or design allows the reaction wheel to be balanced inner portion, of the flywheel limit the amount entirely in its fully assembled configuration, of heat blocked from initial exposure to Earth’s resulting in fine balancing at a relatively low atmosphere. This allows the web of the flywheel cost. to burn away more quickly. The rim of the fly- wheel will then separate, exposing to heat the Patents majority of the material contained in the fly- NASA Goddard is seeking patent protection for wheel itself. Because of the aluminum construc- this technology. tion and the unique cutouts, the flywheel melts

away quickly, efficiently exposing other materi- Licensing and Partnering als to the heat of re-entry. The stator and mag- Opportunities net assemblies in Goddard’s design are located within a center housing, providing an easily This technology is part of NASA’s Innovative demiseable structure that is exposed to the heat Partnerships Program, which seeks to transfer coming in through the flywheel cutouts. technology into and out of NASA to benefit the space program and U.S. industry. NASA invites Why it is better companies to consider licensing the Demiseable Design choices typical of other RWAs, such as Reaction Wheel Assembly technology (GSC- the use of stainless steel or titanium flywheels, 14845-1) for commercial applications. make them unable to demise completely or

For More Information If you are interested in more information or want to pursue transfer of this technology (GSC-14845-1), please contact: Office of Technology Transfer NASA Goddard Space Flight Center [email protected]

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GSC-14845-1 http://techtransfer.gsfc.nasa.gov 12.16.05