In article ,
says...

On 2018-01-31 06:08, Jeff Findley wrote:

snip
If you want to learn more about orbital mechanics, there are lots of
websites that teach the basics. There are also simulators, so you could
see for yourself that entering earth orbit is a waste if your final goal
is earth escape.

Moving the orbit from KSC's natural inclination to that of the
Russian
launch site really, really hurt performance of the shuttle.

Wouldn't this have hurt any launch vehicle equally?


No, the space shuttle was a worst case scenario. Why? Because it put
the ET nearly in orbit. The lightest tanks used, the SLWT, weighted
58,500 pounds empty and that's not including any LOX and LH2 "residual"
propellants still in the tank. Since the ET was being used since launch
(SSME's started firing on the pad), none of that mass was dropped like a
lower stage would have been. That puts it at a disadvantage compared to
a "normal" two stage to orbit launch vehicle which drops the biggest
tanks with the first stage. Yes the shuttle did drop the SRBs, but that
was no different than other launch vehicles that drop solids, so we'll
ignore those.

But that's just the beginning of the problem. The lightest orbiter was
Atlantis which massed 151,315 lb. So, even if we ignore the ET mass,
you're still placing a 151,315 lb orbiter into orbit which does *not*
count as payload to ISS. Note that you're paying the "mass penalty" of
the higher inclination orbit on the entire orbiter mass as well as the
payload, and part of the ET's mass.

Conclusion: The space shuttle orbiter suffers a far greater mass
penalty from increased orbital inclination than a traditional two or two
and a half stage to orbit launch vehicle (e.g. Atlas, Delta, Delta
Heavy, and etc).


Cites:

https://www.nasa.gov/centers/marshal...le_external_ta
nk.pdf

https://en.wikipedia.org/wiki/Space_Shuttle_Atlantis

Jeff
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