That would increase development costs considerably. More likely just
operate out of Brownsville. :-)
On 2016-09-30 15:49, William Claybaugh wrote:
Jon:
Presumably he'll moveTitusville....
Bill
On Friday, September 30, 2016, Jonathan Goff <jongoff@xxxxxxxxx>
wrote:
Bill,
Interesting. I wonder how far away you could break windows with a
28Mlbf behemoth...
~Jon
On Fri, Sep 30, 2016 at 8:43 AM, William Claybaugh
<wclaybaugh2@xxxxxxxxx> wrote:
During ESAS I looked in to acoustic limits at KSC; for 39A, B, and C
the answer was 11.5 million lbsf of thrust, after which windows
start breaking in Titusville.
Bill
On Friday, September 30, 2016, Nels Anderson <nels.anderson@xxxxxxx>
wrote:
Just wondering whether SpaceX's BFR could actually be launched from
Cape
Canaveral, given how noisy it would be.
As a first approximation, I would think acoustic power would scale
as
jet power. Neglecting the fact that nozzles are usually slightly
over-expanded at sea level, this would mean acoustic power scaling
as
the product of thrust and Isp. Per Musk's IAC slides, the BFR will
have
3.6 times the take-off thrust of the Saturn V. Isp will be 334 s,
as
opposed to the Saturn's 265 s. That gives a power ratio of 4.5.
But provisions were made in the design of LC-39 for rockets larger
than
the Saturn. To my knowledge, the largest vehicle seriously
considered
was the MLV-23(L), which would have had four liquid strap-ons with
two
F-1's each for a total of thirteen F-1's. The BFR's thrust is 1.4
times
the 23(L)'s, and the acoustic power is 1.75 times.
If the acoustic intensity follows an inverse-square law, then the
BFR's
window-shattering radius is 1.3 times the 23(L)'s. Of course, since
the
early 60's, population density has grown and regs likely tightened.
And
Musk speaks of multiple launches daily rather than a few per year.
And
low-level clouds reflect sound, invalidating the inverse-square
assumption (if Musk wants to launch with high frequency, weather
constraints will have to be loose).
Are there any mitigating factors? Might the gas-on-gas Raptor be
fundamentally quieter than the liquid-on-liquid F-1? I recall a
claim
by Firestar that mixing affects noise.
