All mission-specific harness stuff. Link to main harness page.
The LI Bus design philosophy, including block diagrams, is summarized on the general harness page.
The harness model philosophy is summarized below by design phase.
Creation of CAD model
Used to determine necessary components and intermodular connection locations
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
Updates to CAD model
Incorporate necessary changes based on developing subsystem design
Changes to assembly as necessary based on breadboard assembly
Updates to CAD model as necessary
Construction of flight model
Space-ready model of satellite
Used to verify resilience to launch loads
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.
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.
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
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.