Cool - thanks!
On Sat, May 25, 2019, 11:39 AM William Claybaugh <wclaybaugh2@xxxxxxxxx>
wrote:
David:
SSTO is cheaper than a TSTO of the same dry mass because staging adds
about 10% additional integration cost (assuming expendables, reusables cost
still more due to recovery and refurbishment costs).
However, TSTO throws more payload into orbit than an SSTO; the best anyone
has ever done with any rocket is about 5% payload (Space Shuttle, counting
the Orbiter as payload) and so it follows that an SSTO w/ that payload
fraction will be lower cost than any similar dry mass and payload
multi-stage vehicle.
This thought experiment overlooks the effect of technology (any technology
that allows 5% payload on an SSTO should improve a TSTO as well) but a more
detailed analysis will show that the effect is very small: at 5% payload
the advantages of staging become small.
Bill
On Sat, 25 May 2019 at 04:24, David Summers <dvidsum@xxxxxxxxx> wrote:
I sense something I could learn from!
Why do you say 5% to be the economical msss ratio? What drives the
numbers?
My guess: engine cost is much higher than tankage, and you drop them with
the tanks?
On Sat, May 25, 2019, 12:08 AM William Claybaugh <wclaybaugh2@xxxxxxxxx>
wrote:
Craig:
Are you being a jerk on purpose or have you just not followed this
conversation?
Second stage of the Saturn 5 was also capable of expendable SSTO if
re-engined with SSME’s. Expendable SSTO has be technically feasible since
the late 1950’s; it simply hasn’t been economic. Nor will it be until 5%
payload fractions are achievable.
Bill
On Fri, 24 May 2019 at 19:01, Craig Fink <webegood@xxxxxxxxx> wrote:
On Wed, May 22, 2019 at 7:34 PM Henry Spencer <hspencer@xxxxxxxxxxxxx>
wrote:
On Wed, 22 May 2019, anthony@xxxxxxxxxxx wrote:Hi Henry,
Wasn’t the former Titan capable of SSTO, assuming a practical “zero”
payload?
The Titan II first stage could even carry a token payload into orbit,
maybe 1t or so if you did things just right
Titan was a missile, how many 1t weapons did it take to orbit?
Or, Ascents did it perform SSTO?
--
Craig Fink
WeBeGood@xxxxxxxxx
