Harness

Overview

All mission-specific harness stuff. Link to main harness page.

Design Philosophy

The LI Bus design philosophy, including block diagrams, is summarized on the general harness page.

Model Philosophy

The harness model philosophy is summarized below by design phase.

Phase A

Creation of CAD model

• • Used to determine necessary components and intermodular connection locations

Phase B

Development of CAD model

• • Used to determine preliminary wiring paths and tie-down points

Construction of breadboard model

• • 3D-printed structural shells and wires

  • Used to verify wiring paths and tie-down points

  • Acquisition of necessary parts

  • Full assembly of satellite harnessing

  • Used to verify wire routing

  • Used to verify harness assembly plan

Phase C

Updates to CAD model

• • Incorporate necessary changes based on developing subsystem design

Changes to assembly as necessary based on breadboard assembly

Phase D

Updates to CAD model as necessary

Construction of flight model

• • Space-ready model of satellite

  • Used to verify resilience to launch loads

Mission and Systems Level Requirements Impact Analysis

The harnessing system for LI Bus will build on the work done in previous missions. However, multiple aspects of the requirements may require modifications to the general harness design philosophy.

The harness team will need to work with the payload team to determine these parameters and ensure that the payload is supplied with all necessary power and data wires. At the same time, the team must chart a path through the payload module for these wires, as well as other wires that must run through to neighbouring modules.

LI Bus also has a 6U form factor, in the shape of two 3U CubeSats joined at the long edges. This means that intermodular connections may not only be along the long axis of the CubeSat, but across its width as well. In this case, the team will have to re-evaluate all harnessing paths and hardware choices. This may present problems, as there will likely be a need for a greater number of harnessing paths within the same module volume. The team must take care so that none of these new paths interferes with component placement.

This analysis is driven by the following mission and system level requirements:

• R-LIB-MIS-001: The LI Bus shall accommodate a generic imaging/remote sensing payload.

  • R-LIB-BUS-078: The Bus shall be capable of providing 10 W of continuous power to payload.

• R-LIB-MIS-007: The LI Bus shall be capable of interfacing with the Rocket Lab 6U canisterized satellite dispenser (2002367F).

For more information about requirements, take a look at the registry in Valispace.

Verification Plan

The harness verification plan is largely based around the model philosophy. It is separated by design phase as follows:

In Phase B, the components will be selected and sourced. Most design-related verification activities will be done in this phase, including inspecting component datasheets to ensure material conformance, and developing a CAD model to determine the harnessing layout. Once these are finished, a preliminary breadboard assembly will be begun to verify the planned harnessing path and accompanying requirements.

In Phase C, the breadboard assembly will be developed further and changed as necessary. The assembly-related requirements will be verified here.

In Phase D, the flight model of the satellite will be created. System level tests will be done here to verify the remaining requirements, including launch environment readiness. The requirements relating to assembly will be verified again here throughout the flight model assembly process.

Assembly Plan

Phase B (Breadboard Model):

• Crimp and solder intermodular cables to pins of connectors

• Install pins into connector housing

• Check each pin for electrical continuity using a multimeter

• Attach connector with soldered wires/cables to mating board-mounted connector using jackscrews

• Insert assembly into structure

• Secure wires/cables as necessary with zip ties

• Inspect to verify bending radii are sufficiently large at all locations

Phase D (Flight Model):

• Cut wires and cables to desired lengths (summarized in spreadsheet yet to be made, link here when done)

• Crimp and solder intermodular cables to pins of connectors

• Install pins into connector housing

• Check each pin for electrical continuity using a multimeter

• Attach connector with soldered wires/cables to mating board-mounted connector using jackscrews

• Insert assembly into structure

• Secure wires/cables as necessary with zip ties

• Inspect to verify bending radii are sufficiently large at all locations

Parts List and Availability

The required list of parts for harnessing is shown below, along with quantities, prices, and links to distributors. As of the last review of this list, all items are in stock and available to be purchased.