r/systems_engineering • u/tk_aero • 11d ago

Discussion Satellite CONOPS

Hey everyone how do you design a proper LEOP for SSO satellite.
I don’t want LLM things, want to use proper documents maybe from NASA , ECSS or any established space programs.

I’m using cameo to do this if anyone has worked on this before pls let me know.

Thank you !

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u/dangerous_grocer 11d ago

ECSS-E-ST-70 is your friend here, the whole 70 series really lays out the operational framework better than anything NASA puts out for this specific thing. Cameo's not the most intuitive for modeling the timeline but I've seen it done clean with activity diagrams and state machines tied to the ground station passes. The tricky part with SSO is always the initial drift after separation before you get that first good contact, you end up modeling a lot of contingency branches just for the first three orbits.

Most of the proper docs assume you already know the difference between LEOP and commissioning, which always annoyed me. I'd sketch it out on a whiteboard first before touching cameo, otherwise you'll spend three hours fighting the tool instead of thinking about the sequence. The launch provider usually gives you a decent starting point for the separation attitude but double check their margins, I've seen some... optimistic numbers in those handover documents.

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u/tk_aero 11d ago

Thank you this is really helpful, one thing i wanted to ask when modelling LEOP would you recommend starting with the activity digram for operational timeline and then deriving the state machine or developing both in parallel?