A kerosene-fueled X-33 as a single stage to orbit vehicle.
in [Physics]
|
Prev: Everything has its own Aether
Next: Fine Particle Physics and the Mathison-Trenite Life Energy Fluctuation Meter (LEF Meter) PART FOUR - {FPP 20090913-draft-V1.0-p4}
From: Sam Wormley on 1 Nov 2009 20:05 Sylvia Else wrote: > Sam Wormley wrote: >> >> If it can be done, great! No Earth-launched SSTO launch vehicles have >> ever been constructed. > > They never will be if we use that as an argument against them. > > Sylvia. What usually comes first is the desire to put a heavy payload into orbit around the earth, sun, or another planet. What rocket configuration can get the job done reliably? That's usually the question, as opposed to what rocket can get the job done for the least cost per payload kg.
From: Sylvia Else on 1 Nov 2009 20:09 Sam Wormley wrote: > Sylvia Else wrote: >> Sam Wormley wrote: > >>> >>> If it can be done, great! No Earth-launched SSTO launch vehicles have >>> ever been constructed. >> >> They never will be if we use that as an argument against them. >> >> Sylvia. > > What usually comes first is the desire to put a heavy payload into orbit > around the earth, sun, or another planet. What rocket configuration can > get the job done reliably? That's usually the question, as opposed to > what rocket can get the job done for the least cost per payload kg. > Depends which market you're in. Space tourism, for example, needs low cost per kg, but not particularly large payloads. Sylvia.
From: Sam Wormley on 1 Nov 2009 20:20 Sylvia Else wrote: > Sam Wormley wrote: >> Sylvia Else wrote: >>> Sam Wormley wrote: >> >>>> >>>> If it can be done, great! No Earth-launched SSTO launch vehicles have >>>> ever been constructed. >>> >>> They never will be if we use that as an argument against them. >>> >>> Sylvia. >> >> What usually comes first is the desire to put a heavy payload into >> orbit >> around the earth, sun, or another planet. What rocket configuration can >> get the job done reliably? That's usually the question, as opposed to >> what rocket can get the job done for the least cost per payload kg. >> > > Depends which market you're in. Space tourism, for example, needs low > cost per kg, but not particularly large payloads. > > Sylvia. I would think that space tourism, would require some margin--some extra safety. "It is extremely difficult to design a structure which is strong, safe, very light, and economical to build. Designers often liken the task to designing and building an egg shell. The problem originally seemed insuperable, and drove all early designers to multistage rockets". "A SSTO vehicle needs to lift its entire structure into orbit. To reach orbit with a useful payload, the rocket requires careful and extensive engineering to save weight. This is much harder to design and engineer. A staged rocket greatly reduces the total mass that flies all the way into space; the rocket is continually shedding fuel tanks and engines that are now dead weight". "Although a SSTO rocket might theoretically be built, margins would be likely to be very thin- even comparatively minor problems may tend to mean that a project to achieve this could fail to achieve the necessary mass-fraction to reach orbit with useful payload".
From: kT on 1 Nov 2009 20:36 Sylvia Else wrote: > Sam Wormley wrote: >> Sylvia Else wrote: >>> Sam Wormley wrote: >>>> Sylvia Else wrote: >>>>> Sam Wormley wrote: >>>>>> Single Stage to Orbit really limits payload "weight". >>>>> >>>>> Why does that matter? The point of an SSTO is to get down the cost >>>>> to orbit per payload kg. An SSTO is likely to mass more than a >>>>> disposable multi-stage for a given payload, but that is not in >>>>> itself a source of concern. >>>>> >>>>> Sylvia. >>>> >>>> http://en.wikipedia.org/wiki/Single-stage-to-orbit#SSTO_Cons >>>> >>> >>> And...? >>> >>> Sylvia. >> >> If it can be done, great! No Earth-launched SSTO launch vehicles have >> ever been constructed. > > They never will be if we use that as an argument against them. That's why I just want to go right ahead and do it, in order to get that 'it can't be done' thing right off the table. Of course the SSME can't be deep throttled enough to do it, but I'd just beef up the head casting and go for it. I suspect bearings and seals might be the first to go. I'm more interested in foamless tank designs with adaptive regenerative pressurization for rapid boiloff recycling. Remember roll control too. > Sylvia.
From: Sylvia Else on 1 Nov 2009 21:12
kT wrote: > Sylvia Else wrote: >> Sam Wormley wrote: >>> Sylvia Else wrote: >>>> Sam Wormley wrote: >>>>> Sylvia Else wrote: >>>>>> Sam Wormley wrote: >>>>>>> Single Stage to Orbit really limits payload "weight". >>>>>> >>>>>> Why does that matter? The point of an SSTO is to get down the cost >>>>>> to orbit per payload kg. An SSTO is likely to mass more than a >>>>>> disposable multi-stage for a given payload, but that is not in >>>>>> itself a source of concern. >>>>>> >>>>>> Sylvia. >>>>> >>>>> http://en.wikipedia.org/wiki/Single-stage-to-orbit#SSTO_Cons >>>>> >>>> >>>> And...? >>>> >>>> Sylvia. >>> >>> If it can be done, great! No Earth-launched SSTO launch vehicles have >>> ever been constructed. >> >> They never will be if we use that as an argument against them. > > That's why I just want to go right ahead and do it, in order to get that > 'it can't be done' thing right off the table. Yes, even a technology demonstrator with an uneconomic payload would be a useful starting point. Isn't that the kind of thing NASA is meant to do? Sylvia. |