Communication Subsystems

Introduction

Johnson Space Center (JSC) offers expertise and unique facilities in which multi-element spacecraft communications subsystems are interfaced with relay satellites and ground elements for end-to-end testing in a controlled radio frequency environment. JSC also provides for design, development, and testing of spacecraft communication systems, including evaluation of electromagnetic radiation properties of antennas and other radiating objects. Explore the communication capabilities below, as we invite you to join us in the exciting journey of space exploration at the forefront of discovery. 

Capabilities

Cable Transfer Impedance and Equipment Shielding Effectiveness Assessment 

Overview | The cable transfer impedance and equipment shielding effectiveness assessment is available. 

Details |

• Testing and measurement of shielding effectiveness of materials
• Capability for quantifying cable coupling and transfer impedance 

Conducted and Radiated Emissions and Susceptibility Testing 

Overview | The JSC EMI Test Facility (JETF) is comprised of two independent shielded test facilities. The JSC EMI Test Facility (JETF) performs testing of systems and subsystems according to MIL-STD 461G requirements. Consultation services can also be arranged for developing a suitable test plan to meet imposed test requirements. 

Details |

• The two independent shielded test facilities have dimensions: 23 feet x 18 feet x 10 feet and 10 feet x 16 feet x 8.5 feet
• Larger Equipment Under Test (EUT) assessments can be accommodated but require additional coordination 

Engineering Support and Evaluation in Shielded Chambers for Conducted and Radiated Emissions and Susceptibility 

Overview | The JSC EMI Test Facility (JETF) supports engineering development and provides EMI/EMC evaluation and qualification. 

Details | Testing of crew, flight, and ground support equipment, including but not limited to communication, instrumentation, biomedical, guidance and navigation, computation and robotics systems is available. Complete EMC testing of systems and subsystems per MIL-STD 461G requirements is performed. 

Reverberation Testing 

Overview | Reverberation is a special type of radiated Electromagnetic Interference (EMC) testing which is sometimes required. 

Details | The JETF can provide reverberation testing in accordance with MIL-STD 461G requirements. 

NOTE: This facility requires longer time to coordinate. 

Antenna Test Facility (ATF) 

Overview | The Antenna Test Facility (ATF) is used to test antenna radiation distribution pattern performance for spaceflight applications in electromagnetic environments conditioned to simulate free space. The ATF includes both a tapered far-field range and a robotic near-field test capability. The near-field range provides flexibility for near-field and far-field antenna radiation distribution pattern and wireless system characterization. 

Details |

Anechoic Chamber Far–Field Test Facility and Robotic Near–Field Measurement Facility 

• Antenna systems design, development, test, evaluation, modeling – using computational electromagnetics (CEM)
• Positioner: 4–axis, Az over EI 
• Over-the-air (OTA) measurements and characterization of wireless systems 
• Computational Electromagnetic Modeling/Analysis validation  
• Frequency range: 400 MHz to 40 GHz
• Dimensions: 150 feet long with cross section approximately 40 x 40 feet 
• Maximum test article size (antenna + in-situ structure) is approximately 28 feet  
• Facility includes single (600 lb. load max) and dual (1200 lb. load max) positioner configurations
• Robotic near-field measurements enable easy in-situ antenna system performance for wireless and communication systems 

Communication Systems Simulation Laboratory (CSSL) 

Overview | The Communication Systems Simulation Laboratory (CSSL) is used for modeling and simulation of both proposed and actual spacecraft communication systems, subsystems, components, and parts. The laboratory hosts high-fidelity computer models of communication systems, detailed structure models, three-dimensional (3D) and planar cuts of antenna patterns, planetary terrain models, and propagation models. 

Details |

• Radio frequency (RF) coverage analysis
• System design and verification 
• Communication system performance 
• Signal analysis 
• Frequency management
• RF compatibility analysis 
• Multipath analysis 
• Communication system anomaly resolution 

Computational Electromagnetics (CEM) Laboratory 

Overview | The Computational Electromagnetics (CEM) Laboratory is used for full-wave, frequency domain electromagnetic simulations. It has been used to support Shuttle, ISS, Constellation, and commercial entities such as SpaceX and Orbital Sciences Corporation. 

Details |

• The lab houses a computer cluster that currently contains 476 processors and 1.95 TB of RAM
• 3D optical scanner for creating Computer-aided design (CAD) models 
• Design and development of microwave devices and antennas 
• Near–field and far–field analysis 
• Radar cross–section calculations
• Antenna coupling analysis 
• Verification of microwave and antenna measurements 

Electronic Systems Test Laboratory 

Overview | The Electronic Systems Test Laboratory (ESTL) is used for design evaluation, radio frequency (RF) interface compatibility, and system performance verification testing of spacecraft RF communications systems and their interfaces with external elements (e.g., ground stations, relay satellites, detached payloads). In the ESTL, multi-element crewed spacecraft communications systems interface with relay satellites and ground elements for end-to-end testing in a controlled RF environment. 

Details |

• End-to-end, high-fidelity communication test bed
• Performance characterization of space communication systems 
• In-depth RF communications performance verification and characterization testing for spaceflight programs 
• Unique test bed for communication systems life–cycle testing 
• Sustaining engineering support during program lifecycle 
• RF characterization testing for payloads, satellites, or other unmanned vehicles
• RF anomaly resolution test bed for prelaunch, real–time, and postflight 
• Support to Tracking and Data Relay Satellite System (TDRSS) Network verification/validation tests, Tracking and Data Relay Satellite (TDRS) checkout, TDRSS Network Firmware checkouts 
• Advanced Communication Protocols Test Bed 
• Evaluation and certification testing of various protocol systems in an end–to–end controlled environment 
• Versatility allows for evaluation of communication, instrumentation, biomedical, guidance and navigation, computation, and robotics systems
• Avionics Government–Furnished Equipment (GFE) development and verification testing 
• Research and Development (R&D) test bed for spacecraft communications 
• Analysis model verification 
• Actual test results used to refine analysis communication models 
• Ultra–High Frequency (UHF), S–Band, X-Band, Ku–Band, and Ka–Band RF spectrum
• Shielded enclosures 
• Breadboard to flight hardware