No CubeSat-compatible, Deep Space Network (DSN)-compatible communications and navigation transponder exists at the time of this reporting. In order for CubeSats and other small spacecraft to go into deep space, a DSN-compatible capability is needed.
Iris is such a communications and navigation X-band deep space transponder consisting of an exciter board (26 dBm output at X-band), a receiver board (–120 dBm sensitivity), a power supply board, two antenna boards featuring four patch antennas (a transmit and receive in each of two directions), and a Marina-2 board for digital signal processing on a Virtex 5 FPGA (field-programmable gate array).
Existing transponders such as the Small Deep Space Transponder (SDST) or Universal Space Trans ponder (UST) are neither small enough nor of sufficiently low power for use on a CubeSat or other nano-spacecraft platform. The INSPIRE CubeSats are 10×10×30 cm in volume. The transponder is restricted to 10×10×5 cm volume, 500 g, and power input, in full transpond operation, of 10 W DC, all of which are about an order of magnitude less than currently available hardware.
The Radio Science Transponder Instrument consists of RF components and an analog phase locked loop backend supporting Doppler and ranging navigation data types only. Iris combines the RF portions with FPGA processing inherited from UST that allows uplink communication with subcarrier, downlink communication with or without subcarrier, Doppler and ranging navigation data types, CCSDS protocol compliance in cooperation with spacecraft C&DH, and an architecture that will support future improvements including more data rates on uplink and downlink, and other navigation data types such as PN regenerative ranging and DOR tones. The architecture will also support proximity operations with RF hardware for different bands (UHF, S-band, Ka-band, or Cband) to provide communications and navigation from mother ships to Irisequipped daughter ships on larger deep space missions.
Numerous CubeSat missions are contemplated that will require high data rates from Earth orbit. Iris firmware can be extended to support Near Earth Network (NEN), and Tracking and Data Relay Satellite System (TDRSS) frequencies and protocols, among others.
This work was done by Courtney B. Duncan, Masatoshi M. Kobayashi, Amy E. Smith, Paula J. Pingree, Maxwell B. Bryk, Fernando H. Aguirre, Igor Kuperman, Edgar H. Satorius, Alfred Khashaki, and Dmitriy Bekker of Caltech for NASA’s Jet Propulsion Laboratory. In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. This software is available for commercial licensing. Please contact Dan Broderick at
This Brief includes a Technical Support Package (TSP).
Iris DSN-Compatible, CubeSat-Compatible Transponder
(reference NPO-49284) is currently available for download from the TSP library.
Don't have an account?
Overview
The document is a Technical Support Package for NASA's Iris DSN-Compatible, CubeSat-Compatible Transponder, developed by the Jet Propulsion Laboratory (JPL). It outlines the transponder's capabilities, specifications, and applications in deep space communications and navigation.
The Iris transponder is designed to operate in environments where traditional GPS is unavailable, such as deep space. It features a simultaneous transmit and receive capability, allowing for a 100% duty cycle during long navigation passes, which can last for hours. This is crucial for missions that require continuous data exchange without the reliance on GPS signals. The transponder employs coherent turnaround techniques for Doppler and ranging, facilitating accurate navigation and communication.
The document highlights the differences between transponders and standard data-only transceivers, emphasizing the unique functionalities of the Iris transponder. It supports various data rates depending on the range, with uplink rates of 1000 bps on a 16 KHz subcarrier and downlink rates ranging from 62.5 bps to over 4 Mbps on different subcarriers. This flexibility in data transmission is essential for accommodating the varying needs of deep space missions.
Additionally, the document discusses the baseband functions and modems associated with the transponder, including uplink and downlink carrier specifications, buffering, and deframing processes. The Iris transponder is built on the Multimission Telecommunications Interface (MTIF) heritage, ensuring compatibility with existing systems and enhancing its utility for multiple missions.
The document also provides contact information for further inquiries and emphasizes the importance of compliance with U.S. export regulations regarding the proprietary information contained within. It acknowledges the government sponsorship of the research and technology development presented in the package.
Overall, the Iris transponder represents a significant advancement in deep space communication technology, offering robust capabilities for future space exploration missions. Its design caters to the unique challenges of operating beyond Earth's orbit, making it a vital tool for NASA and other space agencies engaged in deep space exploration.
