There is no physical reason to expect that.
On 2019-05-25 09:48, Craig Fink wrote:
On Sat, May 25, 2019 at 9:39 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.
https://en.wikipedia.org/wiki/Payload_fraction
The 747 and Concorde are at 50%, I would expect air-breathing to Orbit
to be close to this when it's fully developed.
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:
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
Hi Henry,
Titan was a missile, how many 1t weapons did it take to orbit?
Or, Ascents did it perform SSTO?
--
Craig Fink
WeBeGood@xxxxxxxxx
--
Craig Fink
WeBeGood@xxxxxxxxx
