High-Speed, Low-Cost Telemetry Access from Space

Glenn's revolutionary new multi-tone, high-frequency synthesizer can enable a major upgrade in the design of high data rate, wide-band satellite communications links, in addition to the study of atmospheric effects. Conventional single-frequency beacon transmitters have a major limitation: they must assume that atmospheric attenuation and group delay effects are constant at all frequencies across the band of interest. Glenn's synthesizer overcomes this limitation by enabling measurements to be made at multiple frequencies across the entire multi-GHz wide frequency, providing much more accurate and actionable readings. This novel synthesizer consists of a solid-state frequency comb or harmonic generator that uses step-recovery semiconductor diodes to generate a broad range of evenly spaced harmonic frequencies, which are coherent and tunable over a wide frequency range. These harmonics are then filtered by a tunable bandpass filter and amplified to the necessary power level by a tunable millimeter-wave power amplifier. Next, the amplified signals are transmitted as beacon signals from a satellite to a ground receiving station. By measuring the relative signal strength and phase at ground sites the atmospheric induced effects can be determined, enabling scientists to gather essential climate data on hurricanes and climate change. In addition, the synthesizer can serve as a wideband source in place of a satellite transponder, making it easier to downlink high volumes of collected data to the scientific community. Glenn's synthesizer enables a beacon transmitter that, from the economical CubeSat platform, offers simultaneous, fast, and more accurate wideband transmission from space through the Earth's atmosphere than has ever been possible before.

NASA's newly developed antenna is lightweight (at or below 2 grams), low volume (at or below 1.2 cm3), and low stowage thickness (approx. 0.7 mm), all while delivering high performance (at or above 10 dBi gain). The antenna includes a novel design-material combination in a helical coil conformation. The design allows the antenna to compress for stowage (e.g., satellite launch), then self-deploy at the desired time in orbit. NASA's lightweight, self-deployable helical antenna can be integrated into a thin-film solar array (or other large deployable structures). Integrating antenna elements into deployable structures such as power generation arrays allows spacecraft designers to maximize the inherently limited resources (e.g., mass, volume, surface area) available in a small spacecraft. When used as a standalone (i.e., single antenna) setup, the the invention offers moderate advantages in terms of stowage thickness, volume, and mass. However, in applications that require antenna arrays, these advantages become multiplicative, resulting in the system offering the same or higher data rate performance while possessing a significantly reduced form factor. Prototypes of NASA's self-deployable, helical antenna have been fabricated in S-band, X-band, and Ka-band, all of which exhibited high performance. The antenna may find application in SmallSat communications (in deep space and LEO), as well as cases where low mass and stowage volume are valued and high antenna gain is required.

NASA's patch antenna technology exhibits higher operational bandwidth (on the order of 20%) than typical patch antennas (less than 10%) and can operate across integer-multiple frequency bands (e.g. S/X, C/X, S/C). Testing of the antenna design has demonstrated &#62 6dB of gain on both S and X bands (boresight), with an axial ratio of &#60 6dB and voltage standing wave ratio (VSWR) &#60 3:1 throughout the entire near-Earth network (NEN) operating bands (22.4GHz and 88.4GHz) with hemispherical coverage. The patch size is on the order of 10 x 10 cm and with associated electronics, is about 1 cm in height.

The Space Link Extension Return Channel Frames (SLE-RCF) software library helps to monitor the health and safety of spacecraft by enabling space agency ground support and mission control centers to develop standardized and interoperable mission control applications for space telemetry data. The software library eliminates the need for missions to implement custom data communication designs to communicate with any ground station. The two main tasks accomplished via the SLE-RCF software library are processing user requests and receiving data from ground stations and ground support assets. The software library contains three layers: -SLE (Space Link Extension) for the abstract workings of the protocol -DEL (Decoding and Encoding Layer) to decode and encode the abstract messages used by the SLE layer -TML (Transport Mapping Layer) to transfer the encoded messages via some underlying transport layer protocol, such as as the transmission control protocol (TCP) The library accepts configuration or SLE-RCF directives from the user and responds accordingly. Incoming data, both telemetry frames and status messages, are processed and the appropriate callback routines are triggered by the library.

In traditional hardwired avionics systems, sensor integration requires installation of literally tons of physical cable that significantly increases vehicle weight and the time it takes to develop, maintain, and modify systems. Cabling also consumes space available for profitable payloads. Armstrong's technology uses software to incorporate new wireless capability without physically modifying existing avionics. How It Works Armstrong's gateway uses a software defined radio (SDR) to control the flow of information between various wireless devices and a vehicle's avionics. An SDR can be reprogrammed to communicate with a variety wireless communication protocols and frequencies via straightforward software modules—as opposed to wireless sensor-specific hardware—effectively eliminating the need to modify a vehicle's existing avionics hardware architecture. The gateway employs publish-subscribe network architecture. Before takeoff, flight computers reques—tor subscribe to—specific pieces of information from the SDR gateway. Wireless sensor devices then provide their respective sensor measurements to the SDR gateway, where they are distributed—or published—to any flight computer that has subscribed to a specific measurement. Why It Is Better Armstrong's technology simplifies the process of designing wireless avionics networks by providing a single point of communication between wireless and wired systems. It functions as a layer of abstraction between wireless sensors and the system with which they interface. This approach also ensures that no wireless device can directly communicate with a flight computer unless subscribed prior to takeoff, thus protecting the system from malicious or errant transmissions. Although specifically designed for aerospace systems, the gateway is both platform- and implementation-agnostic, with the potential to foster convergence between wireless technologies and existing systems in other industries. A manufacturer can add industrial Internet-of-Things capability without having to integrate new wireless interfaces into its preexisting network. The gateway serves as a universal interface with virtually any wireless device for such applications as connected logistics, predictive maintenance, asset tracking, and much more.