Here's the Indian EO satellite series Cartosat and their progress over the years. If we kept the development and financed it maybe we could follow a similar path. The satellites, including the cameras were built by ISRO.
Cartosat-1 : launched in 2005 and has camera resolution of 2.5meters.
Cartosat-2 : launched in 2007 and has camera resolution of 0.8meters.
Cartosat-2A : launched in 2008 and has camera resolution of 0.5meters.
Cartosat-3 : launched in 2019 and has camera resolution of 0.25meters.
There are other satellites in the series but I didn't include them to keep it short. Maybe our Indian members could provide us with more details on the program. It's still active and they'll launch more advanced versions.
@Nilgiri @Gessler @Zapper @fire starter
Turkiye is making progress with gokturk series and now imece.
Development of a secure indigenous scalable bus is likely taking shape.
It was by doing this as early as possible that India was able to then keep in touch with sensor module advancement (that you have illustrated with CARTOSAT family)....though our raw throughput scale is still lacking and needs lot more investment as demand grows.
It is only with such a bus family/families that Turkiye will have relatively wide and full customisation options open to it for its birds.
Otherwise external provider (say Thales, EADS, Leonardo, Boeing etc) often limit resource budget in the "export models" they have...commensurate to say political weather (both current and forecast) and so on.
That in turn will always limit capability esp for sensoring or large comms oriented birds.
So even if you have or have access to good sensor module developed by say a research institute (and all the dots and crosses done with ITAR et al. if say there is something American et al. somewhere), the data and/or thermal chokepoint can often be the foreign bus to begin with so its not viable.
This is likely what Turkiye is addressing this decade from what I can see.
In fact I think this is exactly what IMECE is starting right now, as I cannot find any clear mention of the bus on it...i.e its likely first iteration of indigenous one that will be further developed and scaled from operations feedback.
I worked more than 10 years ago on a satellite project payload and having a solid reliable bus (and little paperwork there) is so key to cost and time....
i.e no worries there meant the team can just focus on the other things rather than allocate resource to testing what works and doesn't or have to deal with say some DC bureaucrat(s)/paperwork stuff - all things foreign countries to say 5 eyes-Eurozone will inevitably face if they are ambitious here.
...so I would imagine it is a pretty high initial investment and it needs fording sooner than later by anyone outside this group of countries given these costs only increase with time.