Re: so building a alternative to Galileo seems like a reasonable choice,
@John Smith 19
GPS uses 24 for full time coverage over the entire globe, the current constellation consists of 30 with a few spares planned to launch in the coming years, in polar orbits, with 3 to 4 per orbit, and orbital planes separated by about 60 degrees. Galileo will also consist of 30 operational sats, in 3 orbital planes. For both of these systems you'd be able to lose about half of them without losing coverage completely. You might have a gap in guidance every now and then, but that's about it.
About the size of a smallish bus/largeish van, not including the solar panels but can probably be built smaller
Launch costs depends largely on the launch provider. I'd expect to pay something around 15 to 20 million per sat for a launch on SpaceX vehicle. With some smart mission planning you could probably go for a multi-sat launch so you'd need one launcher per orbital plane. If using Ariane, Soyuz or a ULA offering probably about another 5 to 10 million per sat extra. With a similar constellation to Galileo, launch cost could thus be between 450 and 900 million. In other words, not shockingly expensive compared to the rest of the project cost. Not really a fuckload of money for a government nowadays.
I agree with the statement on implementation though.
Biting the hand that feeds IT
