🚀 go-pugleaf

In article <1992Dec27.163935.20473@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes:
>>...assumption, not a self-evident fact.  Communications networks
>>normally have redundancy to cover predictable single-point failures.
>>Even today's gold-plated satellite networks do, despite the expense.
>
>It's the network reconfiguration costs that get you. When NBC had to
>reconfigure from K2 to SBS 3 due to a control failure on K2, it cost
>NBC $150,000 a *minute* for 4.5 hours until the major ground systems 
>were re-aimed...   Doing it *unscheduled* because of
>a failure of the cheapsat, can be really expensive if it only happens
>once.

Why do you assume that the redundancy will involve repointing?  If you
*plan* for such handovers, you can put the spare satellite in the same
orbital slot as the operational one.  (Those slots are over a thousand
kilometers wide, there's plenty of room.)  Result, no repointing.  Only
the control room needs to even *know* which bird is live.

>>>... and since for most orbits
>>>the satellites aren't retrievable or repairable, and DC won't change
>>>that...
>>Again, your assumption, not a self-evident fact.  Cheap launches change
>>almost everything, including the feasibility of retrieval and repair.
>
>I wasn't aware that DC was planned to have a GEO capability, or a large
>enough cargo bay to retrieve a major comsat.

Why do you assume that DC alone has to do everything?  The big expense
of doing most anything in space is getting into LEO; cutting that cost
massively makes *everything* more feasible.  It becomes much more
attractive to develop a tug capable of bringing things back down from
GEO, or a reentry capsule capable of landing a payload too big for a
DC cargo bay.  Neither of these devices is technologically difficult;
they don't exist at the moment because operations costs -- mostly
the cost of launching to LEO -- are too high.
-- 
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  henry@zoo.toronto.edu  utzoo!henry