🚀 go-pugleaf

In <93004.130256SAUNDRSG@QUCDN.QueensU.CA> Graydon <SAUNDRSG@QUCDN.QueensU.CA> writes:

>>I understood that too.  Perhaps you did not understand what I meant
>>when I said, if there are enough heavy cargoes to justify a new
>>vehicle, it would be more cost-effective to build a larger SSTO
>>than a two-stage kludge?

>Rather depends on how many heavy cargoes there are, doesn't it?

No, I don't think so.  Building and testing a new two-stage vehicle 
would be more expensive than building and testing a new one-stage
vehicle.  So costs would be greater no matter how many, or how few,
payloads you spread them out over.


>As I understand it, the point to an SSTO is to make expendables
>non-cost effective.  So there *won't* be another vehicle fairly
>soon after DC-1's get flying in numbers if they work as advertised.

I don't think Boeing gave up when McDonnell Douglas introduced 
the DC-3.  If one company demonstrates a successful space 
transportation system that makes money, other companies
won't let them have the market all to themselves for long. 


>If there's one or two heavy cargoes a year, Bruce's quick and simple
>second stage might make a great deal more sense than scaling up
>an SSTO design by a factor of five, which I would expect to be quite
>difficult, since it's a complete re-design and probably needs new
>engines.

Bruce's "quick and simple" concept requires *two* new designs.  
You couldn't just put 5x the cargo into an existing DC-1.  Unless
it was unusually dense, it wouldn't fit into the cargo bay.  Even
if you could, the vehicle's balance would be off.  So you're talking
a major redesign, then component testing of both the first and second
stages, then testing both the first and second stages together....

And I can't understand why a larger SSTO would need new engines
while a TSTO with a comparable liftoff weight wouldn't.