Concept of Operations - Primary Payload

• Once Selfie-Sat has been commissioned and is ready for nominal operations, Amateur Radio Operators (“AROs”) from around the world will contact the Mission Control Centre (MCC) in order to request a “Selfie-Sat Pass”. The AROs will send the MCC the location (latitude, longitude) of the centre point of the desired space selfie image.
• The Mission Control Centre will reply to the amateur radio operator with information about the Selfie-Sat Pass start and end times, and a password that the Amateur Radio Operator will use for the pass.
• The MCC will uplink the pass time and required roll angle ( 25 deg) for Selfie-Sat to be able to point the camera boresight (middle of the image) at the AROs specified location during the pass.
• During the pass, the ARO will contact Selfie-Sat directly, and will uplink the command to acquire an image when Selfie-Sat is over the desired imaging area. Only one image will be acquired during a Space-Selfie Pass.
• As soon as the command is uplinked, Selfie-Sat will immediately take the “space-selfie” photo with the Selfie-Cam payload imager.
• Selfie-Sat will then immediately begin to downlink the Space-Selfie photo to the ARO. During a pass, Selfie-Sat may also downlink other information, such as a list of recent downlinks, or other material determined by the CSDCMS (TBD).

CSDC General Rules & Requirements

General Requirements

• The spacecraft shall acquire at most one image per Space-Selfie Pass.
• Operate in Low-Earth Orbit (LEO), between 300 km and 600 km. The design can operate in both a sun-synchronous orbit (Equator Crossing Time of approximately 10:30 +- 1hour), and in the orbit of the ISS (inclination = 51.66 degrees)
  • Will likely be in ISS orbit (secondary payload constraint)
• It shall be possible to determine the spacecraft’s orbit parameters throughout the mission, to accuracy as required by the mission.
• The spacecraft shall be designed for a nominal mission lifetime of one year.
• The spacecraft shall only contain components which can be exported from Canada to any of the following countries without restrictions: India, Russia, United States, French Guyana, New Zealand.

ADCS Specific Requirements

• The coordinate system for the Selfie-Cam operations shall have the Z+ axis towards geodetic nadir, the X+ axis in the orbital velocity direction, and the Y+ axis completing the right-hand axis system.

• The Space-Selfie camera shall be able to be pointed up to 25 degrees off-nadir in the roll axis; the nominal pitch and yaw for Selfie-Cam operations shall be zero degrees.

• The spacecraft attitude shall be controlled (3σ) to an angle no greater than one-quarter of the Space-Selfie camera's along-track and across-track Field-of-View angles.

  For example, at 400km altitude an across-track Field-of-View of 6.0° (full angle) would require across-track attitude control of ≤ 1.5°, in order to ensure that, in the worst cast attitude control situation, the targeted image center point will still be in the image.

• The Attitude Determination subsystem shall be designed so that it is tolerant to at least one attitude sensor failure, and will maintain at least a degraded state of performance.