ICD

The thermal subsystem is capable of standalone testing because it relies solely on its thermal sensors (thermistors) and heaters to evaluate its operational performance. These elements are self-sufficient and do not depend on external power or data from other subsystems during testing.

The design of the thermal subsystem is single fault tolerant through the use of:

• Thermistors:
  
  

  • Multiple automotive-grade thermistors are placed strategically across critical components (e.g CDH, ADCS, Batteries, Reaction Wheel, Payload, Power Board, Communications Equipment, Solar Arrays).
    
    

  • If one thermistor fails, the others continue to provide temperature data, maintaining system integrity.
    
    

• Heaters:
  
  

  • The Minco Heaters installed on the batteries are designed with redundancy in mind. The system is capable of maintaining thermal regulation even if one heater becomes non-operational.
    
    

  • The CDH subsystem is configured to detect heater malfunctions and adjust power distribution accordingly.

The ArcticSat Thermal Subsystem uses radiation-tolerant components to prevent performance degradation due to space radiation exposure.

• Microsemi's SmartFusion2 SoC serves as the main processing unit. this SmartFusion 2 is an ultra-low power, radiation tolerant SoC

• Other thermal components, like thermistors and heaters, are not sensitive to radiation exposure and are chosen specifically for their durability.

The thermal system shall comply with NASA space debris mitigation guidelines as per NASA-STD-8719.14A 

This ensures:

• Reduced risk of contributing to space debris.
  
  

• Safe operation during deployment, mission life, and decommissioning.
  
  

• Compliance with international safety and sustainability practices for space missions.
  
  

The standards can be found in the link below:

According to the Thermal Risk Registry, all components within the thermal subsystem are free of materials listed as hazardous under NASA's guidelines. This includes:

• No use of prohibited substances such as beryllium, cadmium, mercury, or silver, as outlined in NASA safety standards.

• Components are selected specifically for their safety and compliance with environmental and space operation requirements.

The ArcticSat Risk Registry can be found in the link below: 

All spacecraft components for the thermal subsystem shall be electrically bonded according to SSP 30245.

To ensure proper grounding and minimize electromagnetic interference, all structural components in the thermal subsystem are electrically bonded as per the requirements of SSP 30245. This standard guarantees: Effective grounding paths for electrical stability, Protection against electrostatic discharge (ESD) and Compliance with NASA's safety and reliability standards.

The CubeSat design strictly limits the use of non-metallic materials with a TML greater than 1% to prevent contamination and ensure long-term reliability in space.

• The selected material, Henkel Gap Filler 1500, has a TML of 0.41% and a CVCM (Collected Volatile Condensable Material) of 0.05%, meeting NASA standards.
  
  

• This material was chosen specifically for its low outgassing properties and compliance with space-grade requirements.

To meet the standards required by ExoLaunch (the launch provider), any materials identified as stress corrosion susceptible must be properly documented and assessed.

• The Power Subsystem already avoids these materials, and any use in the Thermal Subsystem must be disclosed and verified.

• If such materials are necessary, they will be documented in the ICA (Interface Control Agreement) and subject to screening and approval as outlined by ExoLaunch and MSFC specifications.

To maintain compliance with safety and reliability standards, the thermal subsystem will avoid all materials specified in Table III of MSFC-SPEC-522B (Rev B).

The Power Subsystem already adheres to this standard, ensuring no stress corrosion-susceptible materials are used. Extending this restriction to the Thermal Subsystem eliminates risk of material degradation during the mission

The thermal subsystem shall have no pressure vessels.

The design philosophy of ArcticSat eliminates the use of pressure vessels to enhance safety and simplify subsystem integration. The Power Subsystem already avoids pressure vessels, including electrolytic capacitors and any other pressurized components. This approach is extended to the Thermal Subsystem, ensuring consistent design standards and reduced risk during launch and operation.

Non-Metallic Material Outgassing Requirement:

To meet outgassing requirements, all non-metallic materials in the thermal subsystem must have a CVCM value of less than 0.1%. This prevents the release of volatile materials that could contaminate sensitive surfaces or affect performance. All boards are conformally coated to ensure compliance with this standard, maintaining low outgassing during operation.

The lifetime of ArcticSat is estimated to be at least 3 years under standard orbital conditions.

Acceptable Operational Modes:

The thermal subsystem shall support and remain functional during all primary operational modes, including:

• Science Mode: Data collection and experimental operations.
  
  

• Sun-Pointing Mode: Optimized for solar energy absorption.
  
  

• Detumbling Mode: Stabilization of satellite rotation after deployment.
  
  

• Low Power Mode: Reduced power consumption to extend battery life.
  
  

• Survival Mode: Essential operations only during critical conditions.
  
  

• Critical Hold Mode: Secure state to protect critical systems during anomalies.