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No, because a similar sized LAP can only carry 1/4 the payload; so you only launch as much payload per unit time.
In fact I found an expendable LAP can only carry 1/4 the payload of an expendable TSTO of the same size/GLOW/dry mass.) A reusable LAP would be even worse.
You're not looking at the things that make LAPs useful. Mass is not the figure of merit; cost is.
Careful here, probably not. Price perhaps or more likely: *profit*.
That's why payload is important, because it provides income that leads to profit; and that's why I'm concerned about a 4x reduction in income per flight. My gut feel is that the profit margin isn't necessarily a factor of 4 over cost in the first place.
A LAP platform plus stage to orbit has one complex vehicle and one simpler one, one low maintenance and low performance one, etc. The LAP will be cheaper to design (by far), cheaper to operate from an operational perspective due to simpler recovery, lower performance requirements so lower stress and more robust, etc. Traded off against that is the larger GLOW for the combined vehicle, and correspondingly higher propellant masses and costs.
I think that this is, or may be, swamped by the 4x reduction in income per flight.
There are also strong suspicions that there are LAP/nearlySSTO solutions where it is in fact a lot cheaper, despite the GLOW and propellant costs...
Maybe. I'm not totally convinced.
The other, perhaps better way to go is to differentiate the market and command a higher price per kilogram- it may not matter if it is 4x more expensive if it means you can launch a spy sat every half an hour or something. If having a well designed, simple LAP can do that, then it might be a preferred system after all. Or something.
The devil is in the details. You have to make common assumptions about design parameters and then compare apples and apples.
Sure. But this payload reduction seems to be rather important, and I was getting the impression people aren't completely getting the implications of this particular architecture.
-george william herbert [EMAIL PROTECTED]
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