Electromagnetic Test Engineering Facilities
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Small EMC Facility
Small EMC Control ConsoleSmall EMC Shielded Enclosure

Description:

This facility consists of three contiguous electromagnetically shielded enclosures and an adjoining Computer Room, and is designed for either small satellite or sub-assembly tests. The individually shielded enclosures include the anechoic Test Room, the EMC Control Room, and a Ground Support Equipment (GSE) Room. The Test Room walls and overhead are covered with ferrite tiles and polyurethane wedge absorbers, which provide a minimum of 20 dB absorption of normally-incident , above 20 MHz, electromagnetic waves. A 2.5m long, 1m wide, copper-clad test item mounting bench and cable access panel are located along/on the wall separating the Test Room from the GSE Room.

Mode of Operation:

The test article is installed in the Test Room and bonded to either the copper workbench or to the test article holding fixture and the metallic floor. Interconnecting cables between the test article and its ground support equipment are either connected through access panel-mounted connectors or via two cable ducts (9 cm dia.). Project-furnished test article power line breakout boxes are typically required.

Physical Characteristics:

Experimenter's area: 4m (L) x 2m (W) x 3m (H), Personnel door: 1m (W) x 1.7m (H)
Control room: 7.3m (L) x 3.7m (W) x 3.m (H), Personnel door: 1.32m W x 2.11m (H)
Test area room: 5.5m (L) x 5m (W) x 3m (H), Equipment door: 2m (W) x 2.2m (H)

Test Area Anechoic Characteristics:

Ferrite tiles and carbon-impregnated polyurethane wedge blocks mounted on the interior walls of the test area combine to make the facility a broad band anechoic chamber capable of absorbing electromagnetic waves over the frequency range of 10 MHz to 40 GHz. Field measurement accuracy is thereby enhanced compared to shield room facilities that lack the anechoic material, and radiated susceptibility test signals are controlled with improved signal-to-noise ratios.

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Large EMC Facility

Large EMC FacilityLarge EMC Shielded Enclosure

Description:

The large EMC Facility is designed for testing relatively large satellites requiring a high level of contamination protection. This facility serves as a semi-anechoic or anechoic EMC chamber and maintains a Class 10,000 or 100,000 clean room environment for spacecraft which house particulate sensitive instruments. This results in more efficient operations as air showers and full gowning of personnel is required only to sustain Class 10,000 operations. The Test Enclosure consists of a plywood core, galvanized steel shielded enclosure which generally excludes all externally generated electromagnetic energy. Inside this enclosure is a patterned ferrite-tiled, 20-1000 MHz-effective, anechoic enclosure which reduces internally-generated reflected electromagnetic waves by 6-dB minimum. Selectively placed, carbon-loaded, polyurethane wedge-shaped blocks are wall-mounted on the anechoic enclosure for absorption of signals above 1-GHz.


Mode of Operation:

The test article is installed inside the ferrite enclosure with the microwave absorber panels rolled back. Ground support equipment connections are made through an access panel between the GSE Room and the Test Enclosure either by using a waveguide-below-cutoff cable duct, project-specified panel-mounted connectors, or a set of connectors that duplicate the thermal-vacuum chamber connections (to allow commonality of cable harnesses). The EMC instruments are also connected through an access panel connecting between the Control Room and the Test Enclosure, and between the Control Room and the Data Reduction Room. The test article is bonded to the metallic floor of the Test Enclosure and the earth bonding impedance and room ambient electromagnetic noise are measured and required to test specification limits prior to the start of testing.

Physical Characteristics of Large EMC Enclosure:

Test Enclosure Size: 10m x 12m x 6.7m (H)
Ferrite Tiled Anechoic Enclosure Door Size: 6.5m (W) x 6.2m (H)
GSE Enclosure: Room Size: 6.7m (L) x 5.2m (W) x 3.2m (H).
 Door Size: 2m (W) x 2.5m (H)

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Magnetics Test Site
6.7m Magnetic Field Component Test Facility (MFCTF)

Introduction:

The remotely located Magnetics Test Site contains two major coil systems, 6.7m and 12.8m in diameter, used for magnetic testing of payloads ranging from fully-configured spacecraft down to component level assemblies; and for calibrating torque coils and magnetometers. Both facilities are 3-axis Braunbek coil systems consisting of 12 coils (four coils for each of three orthogonal axes). Each coil contains windings for Earth's field cancellation, static and dynamic field generation, diurnal variation control, temperature gradient compensation, and two sets of spare windings. Due to relatively low usage and high maintenance costs, the 6.7m coil system has been placed on inactive status. The 12.8-m diameter system is also on a reduced availability status requiring a minimun one-week notice before customer test needs can be addressed.

13m Spacecraft Magnetic Test Facility

Description:

The Spacecraft Magnetic Test Facility (SMTF) 13m coil system is one of the three known spherical coil systems of this size in the world. Its geomagnetic field cancellation system is capable of cancelling the Earth's magnetic field within a 1.83m diameter sphere. The SMTF also has a set of 2.9m diameter Helmholtz coils available for perming and deperming spacecraft, and 1.22m and 1.83m diameter coils for magnetically cleaning smaller test items.

Mode of Operation:

Magnetic Dipole Moment Testing: Zero field is first established in the center of the coil. A reference standard proton magnetometer is used to calibrate the coils. For each measurement sequence, the test item and facility dolly are moved to the center of the coil. As the dolly is rotated 360 degrees, three-component magnetic field data is obtained at 10-degree increments. The data are then stored in the computer for immediate display and processing. If the test item exceeds its test limit, compensation magnets can be developed to reduce the dipole moment to acceptable levels.

Spacecraft Magnetometer Calibration: Initial setup is similar to magnetic dipole moment testing. The test item is positioned in the center of the coil and aligned with the coil axes. Static and dynamic fields are generated to establish linearity, frequency response, zero offset, and alignment characteristics of the test item. The data system can be used to collect, store, and display test parameters.

Parameters:

Static Field Capability
Dynamic Field Capability
Magnitude (each axis):
 ± 60,000 nanotesla
Magnitude (each axis):
 ± 60,000 nanotesla
Resolution:
 ± 0.1 nanotesla
Resolution and stability:
 ± 2%
Stability:
 ± 0.5 nanotesla
Frequency:
 0 to 100 rad/sec
Homogeneity:
 0.001% (1.83m, 6' dia spherical volume)    

Physical Characteristics:

Coil access opening:3.05m (W) x 3.05m (H)
Building access opening: 4.27m (W) x 4.57 (H)
Hoist lifting capacities (4): 4,536 kg , 2,722 kg , and two each 2,268 kg

Integral Instrumentation:

The SMTF is equipped with single and triaxial magnetometers, proton magnetometers, torquemeter, and data collection instrumentation. It contains the three Helmholtz coils described above, with associated AC and DC power supplies.

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