In article ,
says...

On 2018-11-18 21:38, Jeff Findley wrote:

The cargo version of BFS will have a large payload bay .

ok, so there will be a cargo version. Wasn't aware of that. Had only
seen the draw2ings for the cruise shop with hundred+ passengers to Mars.

There are three BFS versions: crew, cargo, and tanker. Trips much
beyond LEO need refueling and that's best done with dedicated tankers
where the majority of the "payload" is actually propellant tanks used to
refuel other BFS vehicles. These three basic designs all share the same
mold lines, structure, engines, TPS, and etc. They're all the same
basic "type" just like a passenger 747 versus a cargo 747.

the payload bay door(s) will open and the satellites will be released in
sequence just like Iridium satellites are released from a Falcon 9 upper
stage.

So the payload bay will be fitted with the satellite release mechanism
specific to those stalellites, right? Sort of like the Shuttle payload
being fitted with multiple PAM launchers ?

That's not crystal clear at this time. They could stick with the EELV
style standards (just more than one at a time in the bay) enabling
payloads to be integrated just as they are today. Again, look at what
they do for Iridium launches. The Iridium satellite dispenser attaches
to the upper stage just like all other payloads (i.e. it bolts to the
standard payload interface).

Or they could come up with a dedicated BFS cargo design just for their
own Starlink satellites to maximize the number launched per flight
(again, vertical integration). The point is we don't know the details.
Likely SpaceX doesn't know either since they've got another major
iteration of BFR in the works.

SpaceX isn't afraid to change designs when needed.

I don't understand your point. Since it's a global satellite network,
you put the ground terminals exactly where they're needed.

In Canada, unlike the USA, the vast majority of the area where services
are needed do not have any fibre ANYWHERE near, so you can't place the
ground stations where they are needed and need to aggregate traffic to a
satteline that is over a ground station.

So to serve a town like Resolute Bay at 73° latitude, the satellite that
passes overhead may have to pass the signals down to another and then
another to reach one that is over a ground station. The thing is that
ground station will end up service a verty large area of northern Canada
and thus aggregate a lot fo traffic and this is where the uplink
capacity matters.

Are you forgetting this network will have 12,000 satellites? That's
where the capacity comes from. They've greatly increased the size of
the in space network since this was first proposed. There will be "a
few" more than one satellite overhead at a time.

Again, you have no idea what Starlink's pricing will be.

If you think it will be radically lower than existing services you are
mistaken. Especially since Musk has stated it needs to generate revenue
to find BFR/BFS, and once they realise how much gorund infrastructure
they will need to support users worldwide, you'll find the costs go way up.

The price of the launch is one thing. But if you have demand for X
capaxity, but your system only provides for half of that, then you price
service high and/or impose usage limits or lower speeds to limit demand
for capacity which you don't have. If you oversell the service (as
Xplornet does), then you get a terrible image and people hate you.

Starlink just has to price themselves enough below the existing
providers to steal their customers. In response to that, the existing
providers will need to lower their prices, as much as they can, in order
to retain as many customers as possible. If they lower their prices
below Starlink, then Starlink will need to cut their prices to remain
the lowest cost provider.

This is a supply and demand driven global free market. If you think
prices will remain high as more providers enter the market (as you said,
SpaceX isn't the only company trying to build a large constellation),
you're sadly mistaken.

reusability. Starlink will get those launches at cost too. They'll be
far cheaper than launches for any other LEO network.

Getting launches at cost doesn't matter. It's all book keeping. What
matters how how much will be oeration costs, groudn station costs and
how much revenues they will get. (and factor in need to lauhch X
satellites per year to replace falling ones in the longer term)

Launch cost is a portion of overall costs. Yes those other costs
matter. SpaceX is deliberately making their network out of numerous
satellites. If a few fail, so what? That's taken into account via
spares in orbit. Iridium already does this.

As for ground station costs, that's why SpaceX is looking to build many
ground stations around the planet. This isn't at all like owning a few
GEO comsats with very few dedicated (uplink) ground stations for each
comsat. This is a network with almost 12,000 satellites talking to
hundreds of ground stations located strategically around the planet to
provide service to millions of customers.

Jeff
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