High Level Design Requirements

These represent estimated requirements for the team to discuss, elaborate on, and push back on.

Informed by Concept of Operations Satellite Requirements Mission life: 1 year Bus size 1U Bus weight 1 kg Orbit: LEO, any inclination (ISS) Individual subsystem failure should not affect any other subsystem in the short term(power distribution and structure notwithstanding) No liquids, gasses, pressure vessels, thrusters, fire All subsystems must have serial communication interfaces and controllable by the OBC Position knowledge: < 300km Single ON switch Comms Downlink and uplink combined 120 kbytes per day Frequency must be ITU amateur satellite sanctioned Power2 Attitude Determination & Control Determination accuracy of <10 degrees in three axis de-spin and stabilization for post deployment spins of up to 30deg/s Continuous single face pointing capability of nadir +/- 10 degrees except for the axis in the direction of said face State switching Able to enable Low Power for each subsystem Able to turn each sub system off and on Command and Control Execute commands immediately or time delayed up to 7 days into future Able to validate command receipt and execution Non-volatile storage: ability to store health monitoring data, config files, job queue, s/c states for 7 days. Thermal Passive thermal control for PCBs Battery: Active thermal control Health Monitoring Subsystem level thermal shutdown Subsystem level latchup detection and reset Temperature and current monitoring at subsystem level Subsystem level recovery routines for SEL, SEU, infinite loops Structural No moving parts (with the exception of deployable antenna) Launch survivability, should not liquify on launch Cubesat launcher standards Total Mass loss from outgassing less than 1% Payload Peak power 2W 5% duty cycle 1U, 1kg Fixed attitude requirements (no major attitude correction in orbit) 7 month unpowered room temp storage Payload should include its own processing and data storage

CSDC Requirements

2.1 Spacecraft Structure and Materials

[DIETR-0010] Configuration and Dimensions:  This size and configuration is called a “3U” or triple-cubesat. These dimensions apply to the spacecraft in the stowed (launch) configuration only. [DIETR-0020] Co-ordinate System:  The spacecraft shall use the co-ordinate system as defined in Figure 2-3. The -Z face of the spacecraft will be inserted first into the dispenser. [DIETR-0030] Spacecraft Structure Material:  Aluminum 7075, 6061, 5005, and/or 5052 shall be used for both the main spacecraft structure and the corner rails. [DIETR-0040] Surface Protuberances:  Protuberances are permitted on the spacecraft XZ and YZ faces (i.e., the 100.0 x 340.5 mm spacecraft surfaces) inside the rails; however, protuberances shall not exceed 6.5 mm normal to any of these faces. Comment: This requirement applies to the spacecraft in the stowed (launch) configuration only. [DIETR-0045] Corner Rails:  The spacecraft shall have four (4) rails, one per corner, along the Z axis. Rail surfaces that contact the launch dispenser guide rails shall have a hardness equal to or greater than hard-anodized aluminum (Rockwell C 65-70). :[DIETR-0050] Corner Rail Anodisation: The spacecraft corner rails and standoffs shall be hard-anodised in order to prevent coldwelding within the dispenser.