The SCaN Testbed will consist of reconfigurable and reprogrammable SDR (Software Defined Radio) transceivers/transponders operating at S-band, Ka-band, and L-band, along with the required RF/antenna systems necessary for communications. Designed to operate for a minimum of two years, the three SDRs will provide S-band duplex RF (Radio Frequency) links directly with the ground, [also referred to as the Near Earth Network (NEN)], S-band duplex RF links with the TDRSS (Tracking and Data Relay Satellite System), [also referred to as the Space Network (SN)], Ka-band duplex with TDRSS, and L-band receive-only with the GPSS (Global Positioning Satellite System). The SCaN Testbed will be in low earth orbit and has multiple antennas providing connectivity to a series of NASA Space Network (SN) TDRSS satellites in geosynchronous orbits and NASA Near Earth Network (NEN) stations. The major components of the SCaN Testbed are shown above
The SCaN Testbed uses a frequency assignment between ISS and TDRS at S-band and Ka-band to send and receive data from the radios and antenna system. SCaN Testbed commands are sent from the CoNNeCT Control Center located within the GRC Tele-Science Support (TSC) to the radios to configure and operate each radio. Communication with the SCaN Testbed through ISS is considered the primary path, this includes the wired path between the SCaN Testbed and ISS and the wireless path from ISS to the WSC (White Sands Complex ). The WSC is wired to the remaining ground station facilities consisting of the HOSC (Huntsville Operations Center), the NISN (NASA Integrated Service Network), and the CCC (CoNNeCT Control Center) located at GRC (Glenn Research Center), the CoNNeCT Experiment Center (CEC) is also part of the CCC.
A RF data connection will provide a direct bi-directional connection between the radios and ground stations. This second communication path (commanding and bidirectional data) is the experimental link with the SN and the NEN, this is the wireless path between the SCaN Testbed and Ground Stations such as the Wallops Ground Station. The TSC facility, located at GRC, allows payload developers and scientists on Earth to monitor and control experiments onboard the ISS (International Space Station). Data from the radios are received at the White Sands Complex, Las Cruces, NM via TDRS and routed to GRC. For Global Positioning System (GPS) experiments, the JPL radio is configured to receive and process GPS signals. Data is collected on-board and sent to ground via TDRS or the primary path.
S BAND TTC antenna (Telemetry, Tracking and Control)
Galileo Ground Segment
TM/TC: Telemetry/Telecommand
Galileo UHF Search and Rescue Antenna, pdf
Conical Logarithmic Spiral Antenna:
offers circular polarisation over approx. one decade up to microwave frequencies.
Frequency Range: 1 - 10 GHz (max @ 1-2 GHz) (aka frequency independent)
Polarisation: circular polarisation
similar conical spiral antenna on CSS:
NASA Tracking and Data Relay Satellite TDRS
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