Development of a Low-Flying CubeSat Mission for F-Region Characterization

Plasma irregularities in the F-region (200-800 km) of the night-time equatorial ionosphere have been shown to significantly influence the performance and reliability of space borne and ground based radio communication systems. Equatorial Spread-F (ESF) episodes may cause the disruption of satellite operations, communications, and navigation due to backscatter and radar scintillation. Current records of rocket, satellite, and radar data are not of sufficient quantity to allow for accurate models and predictions of the spectrum of irregularities. To provide a better understanding and predict F-region phenomena that may disrupt communications, it is important to perform in situ, or local, real-time measurements in areas that these irregularities begin. Typically, satellite orbits at altitudes in the bottomside F region have a very limited lifetime due to atmospheric drag. The objective of the Low-Flyer CubeSat mission is to provide scientific data through improved in situ instruments and methods to better characterize the F-region of the ionosphere. Achieving low altitudes near 200 km while still enduring a mission lifetime that encompasses each season, the Low-Flyer CubeSat mission intends to implement an elliptic orbit through the use of on board propulsion. This presentation will overview the technical details and operation of this unique CubeSat mission

Link Adaptation for Mitigating Earth-To-Space Propagation Effects on the NASA SCaN Testbed

In Earth-to-Space communications, well-known propagation effects such as path loss and atmospheric loss can lead to fluctuations in the strength of the communications link between a satellite and its ground station. Additionally, the typically unconsidered effect of shadowing due to the geometry of the satellite and its solar panels can also lead to link degradation. As a result of these anticipated channel impairments, NASA's communication links have been traditionally designed to handle the worst-case impact of these effects through high link margins and static, lower rate, modulation formats. The work presented in this paper aims to relax these constraints by providing an improved trade-off between data rate and link margin through utilizing link adaptation. More specifically, this work provides a simulation study on the propagation effects impacting NASA's SCaN Testbed flight software-defined radio (SDR) as well as proposes a link adaptation algorithm that varies the modulation format of a communications link as its signal-to-noise ratio fluctuates. Ultimately, the models developed in this work will be utilized to conduct real-time flight experiments on-board the NASA SCaN Testbed

Heliophysics and Amateur Radio:Citizen Science Collaborations for Atmospheric, Ionospheric, and Space Physics Research and Operations

The amateur radio community is a global, highly engaged, and technical community with an intense interest in space weather, its underlying physics, and how it impacts radio communications. The large-scale observational capabilities of distributed instrumentation fielded by amateur radio operators and radio science enthusiasts offers a tremendous opportunity to advance the fields of heliophysics, radio science, and space weather. Well-established amateur radio networks like the RBN, WSPRNet, and PSKReporter already provide rich, ever-growing, long-term data of bottomside ionospheric observations. Up-and-coming purpose-built citizen science networks, and their associated novel instruments, offer opportunities for citizen scientists, professional researchers, and industry to field networks for specific science questions and operational needs. Here, we discuss the scientific and technical capabilities of the global amateur radio community, review methods of collaboration between the amateur radio and professional scientific community, and review recent peer-reviewed studies that have made use of amateur radio data and methods. Finally, we present recommendations submitted to the U.S. National Academy of Science Decadal Survey for Solar and Space Physics (Heliophysics) 2024–2033 for using amateur radio to further advance heliophysics and for fostering deeper collaborations between the professional science and amateur radio communities. Technical recommendations include increasing support for distributed instrumentation fielded by amateur radio operators and citizen scientists, developing novel transmissions of RF signals that can be used in citizen science experiments, developing new amateur radio modes that simultaneously allow for communications and ionospheric sounding, and formally incorporating the amateur radio community and its observational assets into the Space Weather R2O2R framework. Collaborative recommendations include allocating resources for amateur radio citizen science research projects and activities, developing amateur radio research and educational activities in collaboration with leading organizations within the amateur radio community, facilitating communication and collegiality between professional researchers and amateurs, ensuring that proposed projects are of a mutual benefit to both the professional research and amateur radio communities, and working towards diverse, equitable, and inclusive communities

Geolocation of RF Emitters with a Formation-Flying Cluster of Three Microsatellites

In 2017, the HawkEye 360 Pathfinder mission will demonstrate the capability to perform high-precision RF geolocation using a formation-flying cluster of microsatellites. HE360 has developed an innovative combination of classical and novel geolocation algorithms that will enable precise geolocation of RF emitters related to a broad array of business enterprises. These algorithms are robust to errors in self-reported geolocation data such as those commonly seen in maritime radio service systems like the Automatic Identification System (AIS). Each spacecraft in the Pathfinder cluster will host a primary payload consisting of a Software Defined Radio (SDR) capable of covering various RF segments spanning VHF through Ku-Band. The spacecraft will leverage formation-flying techniques and propulsion technology demonstrated on earlier cubesat missions to maintain a loose, long-term, geometrically diverse formation where all three spacecraft have co-visibility of the signal of interest. This paper describes the challenges associated with the demanding requirements of this Pathfinder mission, the technology and architectural approach that enable it, and the value of independent geolocation services to commercial, governmental and humanitarian concerns. Furthermore, a future mission consisting of an expanded constellation of similar clusters will be explored

Multipersona Hypovisors: Securing Mobile Devices through High-Performance Light-Weight Subsystem Isolation

Funded by Naval Postgraduate SchoolWe propose and detail a system called multipersona Hypovisors for providing light-weight isolation for enhancing security on Multipersona mobile devices, particularly with respect to the current memory constraints of these devices. Multipersona Hypovisors leverage Linux kernel cGroups and namespaces to establish independent process container, al-lowing isolation of the Multipersona process tree from other simultaneous instances of Multipersona and the hypovisor which is an underlying Angstrom-based embedded Linux distributions designed to add additional security to the system. The system incorporates a wide range of data integrity tools in the embedded hypovisor, and an SE Linux-enabled kernel for mandatory access control and integrity tools for transparent auditing of running Multipersona instances. A prototype is presented which uses integrity tools external to the Multipersona container to audit it for malicious activity, and also has the ability to support a multipersona environment with multiple encrypted personas existing individually or simultaneously on the device. Two versions are demonstrated, one which allows cold-swapping of personas for high-assurance scenarios and also one that supports hot-swapping. Analysis shows that the hypovisor has a 40-50 MB impact on the overall memory footprint for the system.Naval Postgraduate School under contract N00244-11-P-2026L-3 Communications National Security Solutions CenterN00244-11-P-202