Harness

Overview

This page contains all mission-specific ArcticSat harnessing information. For more harnessing information, see the main harness page.

Design Philosophy

The ArcticSat harness 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

Preliminary Layout

The harnessing layout depends completely on the relative position and orientation of each ArcticSat structure module. Since this plan is still under development, the harnessing cannot yet be physically laid out to completion. The naming convention for the intermodular connectors can be found on the general harness interface control page. Some preliminary pinout concepts can be found on the interface control page.

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.

Test Plan

Most required tests for the harnessing subsystem come at the system level for acceptance to the launch and orbital loading environments. These will be performed with the flight model in Phase D. All other required tests relate to the proper assembly of the system and are discussed in the assembly plan.

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

Mission and Systems Level Requirements Impact Assessment

The harnessing system for ArcticSat will be very similar to that of previous missions. The only major difference will be the payload module. Iris had an array of geological samples and two cameras, whereas ArcticSat has a large deployable antenna.

The harness team will have to chart a new cable routing path through the payload module. An important consideration here is to ensure that the harness does not impede the deployment of the payload. The working volumes for the stowed and deployed configurations of the payload will be used to determine what area needs to be kept open for the deployment process, and the harness will have to keep outside this area. Collaboration with the payload team is necessary to ensure that harnessing considerations do not go unnoticed.

Additionally, the previous harness standard included a 24 AWG wire rated for a maximum of 2A. The maximum current through the Iris harness was 1.8A for the solar panel deployment mechanism. It is possible that ArcticSat's payload might require a greater current to be deployed. As such, the ArcticSat harness team must collaborate with the power team to determine the greatest current the satellite requires, and select a wire accordingly.

The driving mission and systems level requirements for this preliminary analysis are:

• R-ARC-MIS-001: The mission shall be capable of measuring novel ice melt data in the Canadian Arctic Archipelago (CAA) using a passive radiometer.

• R-ARC-MIS-002: The mission shall revisit the Greenland and Arctic ground targets every 12 hours.

• R-ARC-BUS-174: The bus shall be capable of measuring TBD type of ice data from an altitude of 525 km. 

• R-ARC-MIS-007: The mission shall have a lifetime of at least 3 years.

• R-ARC-BUS-169: The bus shall be capable of supplying enough power to all subsystems to run nominal mission operations for at least 3 years.

• R-ARC-MIS-009: The mission shall be capable of transmitting data to Chesterfield Inlet.

• R-ARC-BUS-021: The bus shall be able to transmit data to licensed ground stations.

For more information on the requirement hierarchy, see the requirement registry in Valispace.

Preliminary risks for the harness subsystem are summarized below.

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.

Bill of Materials (BOM) 

The BOM for Harnessing is shown below. All components and their materials are complaint with requirements.