In article 8b8f5fa9-b811-46a0-8068-
, says...

If we could go back in time before US shuttle began flying which
design shuttle or buran would be better? and why?

Buran, but only because Energia was capable of putting Buran nearly into
orbit by itself. Because of this, Energia could be used to launch other
payloads than Buran. Note that this was attempted once, but the launch
failed due to the payload trying to perform its orbital insertion burn
in the wrong direction. In other words, it deorbited itself instead of
orbiting itself. From what was reported, Energia performed well both
times it flew.

Energia was designed to be modular and could be launched with various
numbers of (liquid fueled) boosters strapped to its sides. For a
shuttle launch, it needed four boosters. Its boosters are also
(essentially) the first stage for Zenit-2. (also the basis for the
three stage Sea Launch vehicle). For an "Energia M" launch, it would
have used two. If a truly huge payload needed to be orbited, Energia
could conceivably have been flown with more boosters (resembling the
Vulkan launcher).

Energia
http://www.buran-energia.com/energia/energia-desc.php

Energia M
http://www.buran-energia.com/energia/energia-M-desc.php

Vulkan
http://www.buran-energia.com/energia...ulkan-desc.php

Zenit-2
http://www.buran-energia.com/energia...zenit-desc.php

Again, their "shuttle" design is better not so much because of the
shuttle design, but because it was separate from the launcher design.
Furthermore, the launcher design was modular and supported an entire
range of payloads from Zenit-2 to Vulkan (or a similar Energia).


Unfortunately, the demise of the Soviet Union meant an end to both Buran
and Energia. Otherwise, it could have been used to orbit very large
payloads (e.g. space station modules) in one launch. Buran could have
been used to service the space station (much in the same way that the US
space shuttle did with Mir and ISS).

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer