Harness Tests

Item: P1
Test Item: Visual Inspection
Test Specification: Visually inspect connector connections and wiring going from each connector.
Judge Criteria: No disconnect in wires to the connector.
Test Period: EM
- - Start Date: Nov 8,2024
  - End Date: Nov 15, 2024
Test Equipment: EPS boards (3 PWAs)
Major Problem:
Warning: Use the ESD safe mat for all these inspections.
Recommendation:
Raw Data:
- - Connector : Pass/Fail: Initial:
  - ADCS to CDH Pass EVS
  - ADCS to Power Pass EVS

Pictures from test:

ADCS to CDH:

ADCS to Power:

2. Measurement of length and mass of the wiring

Item: P2
Test Item: Measurement of length and mass of the wiring.
Test Specification: Measure the length of each wire in the harness as well as the mass of each connector.
Judge Criteria: All wires are the correct lengths and mass needed to make proper connections.
Test Period:
- - Start Date: Nov 8, 2024
  - End Date: Nov 15, 2024
Test Equipment: EPS boards (3 PWAs)
Major Problem:
Warning: Use the ESD safe mat for all these inspections.
Recommendation:
Raw Data:
- - - Connector: Weight: Length: Initial:
    - ADCS to CDH 14.67 g 14 cm EVS
    - ADCS to Power: 23.95 g 29 cm EVS

Photos of connectors being weighed:

3. Continuity Test

Item: T1
Test Item: Continuity
Test Specification: Continuity check the connections to verify that the signal and power wires connect to the correct points on the connectors.
Judge Criteria: All power and data wires shall show a small resistance (<0.1 ohms). The pinouts shall match the harness diagrams listed in ICD.
Sample(s): EM, FM, FLATSAT
Test Period:
- - Start Date: Nov 15, 2024
  - End Date: Nov 15, 2024
Test Equipment: EPS mat [ only required when electronic boards are connected], digital multimeter, harness connectors, test PCB.
Major Problem:
Warning:
Recommendation:
Raw Data:
- - Connector #: Comments Initials:
  - ADCS to CDH PASS EVS
  - ADCS to Power PASS EVS

Photos from connectivity test:

Detailed Instructions:

The following is a picture of the Connectivity Test PCB made:

Figure 1: Connectivity Test Jig PCB

Connect the male connectors to the built pcb jig.
Connect the fully assembled female connectors on each side of wires.
To test connectivity, apply the multimeter to one of the plates of connector 1 and a connecting plate of connector 2 to confirm a connection is there.

4. Wire Tension

Item: T2
Test Item: Wire Tension
Test Specification: Test pull strength/ tension of the wire to verify that the assembled wires can withstand the satellite vibrations, launch conditions, assembly tensions.
Judge Criteria:
- - All power wires shall withstand a pull force of [TBD]
  - All data wires shall withstand a pull force of [TBD]
  - Must comply with Table 12.1 of NASA STANDARD 8739.4A

Sample(s): EM, FM, FLATSAT
Test Period:
- - Start Date:
  - End Date:
Test Equipment: ESD mat [only required when electronic boards are connected], harness connectors, weight, wire pull test jig/ equipment.
Major Problem:
Warning:
Recommendation:
Raw Data:
- - Connector #: Pinout AWG Tensile Strength

Detailed Instructions:

There are two types of ways to do this test:

The Built Test Jig:

Figure 2: Build test jig idea for testing breadboard and EM models outside the cleanroom.

This can be done with the M80-4C11205F1-02-325-00-000 (Female Connector) that is either fully assembled or partially assembled. Partially assembled being testing one wire pinout at a time. If the test equipment is:

Attach connector and wire to the test jig. The mass is determined by using the table in the appendix. This table is based on the gauge of the wire being tested and the minimum force needed to withstand before breakage of the crimp of the wire.
Start timer and allow mass to hang.
Record the time that it takes for the wire to break connection and fall.

2. ALPHATRON MPT-200A (Test Equipment)

The second this is done with the wires individually.

Figure 3: Demo test being done on ALPHATRON MPT-200A.

Testing LISSA's Payload Interface with New Intermodular Connectors

We conducted additional testing using the 3D-printed FM board and the new data and power intermodular connectors to evaluate how LISSA interfaces with the payload. As shown in the layout below (Figure 4) , the intermodular data connector on the payload board connects directly to the corresponding data connector on the power board. However, since the payload requires regulated power from the regulator board, the intermodular power connector on the payload board must connect to the corresponding power connector on the regulator board, which requires a longer cable. To assess this, we carried out testing using mock boards.

Figure 4: Interface of LISSA bus with payload

Figure 5, 6: The data connection comes from the power board, and the regulated power is supplied through a dedicated power connector on the regulator board.

Figure 7, 8: The power and regulator boards are housed inside the FM shells. The setup demonstrates the extra wire lengths needed to ensure sufficient slack and stress relief. Any excess wiring will be neatly stacked in the second payload module.

Based on our evaluation and wire measurements, the optimal lengths—accounting for sufficient slack and stress relief—are 12 cm for the data wire and 24 cm for the power wire. This was part of an initial test, and while these lengths may be slightly longer than necessary, it’s safer to have extra length rather than too little, as we can always trim them later if needed. Additionally, according to input from the payload team (Bornea), there is enough space in the second payload module to accommodate and neatly stack any excess wiring.

Also, based on our recent communication with Bornea, they are currently using the same intermodular data and power connectors as those used in the LISSA bus. The links to these connectors can be found below.

Data intermodular connectors (Female part):

https://www.mouser.ca/ProductDetail/Harwin/M80-4613405?qs=7jyBjEprRBh0V6ACNktP4g%3D%3D

Power intermodular connectors (Female part):

https://www.mouser.ca/ProductDetail/Harwin/M80-4000000F1-02-325-00-000?qs=N%2F3wi2MvZWA%252BU4nhYmPXlg%3D%3D

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