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Parameter | Requirements | Justification | |
---|---|---|---|
Mechanical subsystem | |||
Payload physical envelope | |||
Payload mass | |||
Camera aperture placement | Zenith panel Flush with panel? | ||
Power subsystem | |||
Payload energy consumption | 3 W for 3 minutes observation pr. pass | Estimation. Target observation time expected to be shorter than 3 minutes | |
Peak power needed | > 10 W | Should be able to operate TM/TC, downlink radio, ADCS and payload at once during target pass. | |
Energy needed | Should be able to perform target observation (inkl. slewing maneuvering) and downlink for four consecutive passes | ||
Communications | |||
Downlink data rate (usable bits) | 1 - 2 Mbit | Estimation of size of one target measurement packet, one pr. pass: 500 pixels x 500 pixels x 2 bytes/pixel x 10 channels = 5 Mbytes = 50 Mbits 10 kanaler er typisk det vi får med komprimering i spektralt domene basert på IDLEtechs / Harald Martens teknologi. | |
Downlink frequency band | 2200-2290 MHz (S-band) 8025-8400 MHz (X-band) | Used for non-commercial services. Information from NRS. TBC. Alternative? | |
Downlink power/EIRP needed | Depending on GS antenna size, power available and freq. band | ||
Downlink radio energy consumption | Ground station pass expected to be 8 5 < t < 12 min. Max 12 min in second pass depending on orbit type. One downlink pass pr. target observation. 3-5 revisits achievable. | ||
Ground station/data access | Depending on frequency band If possible, GS at NTNU, in addition to others | ||
Launch and orbit | |||
Orbit type | High-LEO/Polar (may or may not be SSO) | Target area is far north, ground stations expected to be far north | |
Orbit height | 400 - 600 | Low orbit preferable due to better resolution | |
Orbit inclination | 75-98 deg | Referred to orbit type | |
Other parameters | Ω: 30 - 45 deg or Ω: 210 - 225 deg Ascending node Node drift | Pass should be close to mid-day over target area for best light conditions Should be limited to ensure satellite pass by target area day-time during summer/autumn time | |
ADCS | |||
Slewrate (max, precision) | 2 deg/s | In order to be able to point towards target during a pass | |
Pointing accuracy | 0.1 deg TBC (0.01) | The higher the better, although requirements may set it to even higher pointing accuracy requirement. | |
Momentum budget | Satellite must be able to perform slewing manouver for four consecutive passes | ||
Peak power needed during slew |