"Dholmes" wrote in message .. .
"ed kyle" wrote in message
om...

Only if CEV weighs 50,000 pounds. It should weigh much less
than that.

After all, 3-man Soyuz TM weighs only 7.15 metric tons
(15,766 pounds). Shenzhou is believed to weigh about 7.8 tons.
A straight Delta IV-Medium (no strap-on boosters even) can put
at least 10.5 metric tons into LEO (the most recent such rocket
put 10.56 tons into a 186x401km parking orbit, not counting the
dry mass of the second stage).

I think you may be in for a rude shock.
From what little I have seen we are talking about just under 50,000 pounds
of which 2/3's will be fuel.

That might make sense for a trans-lunar CEV, but it is
way beyond overkill for a LEO/ISS CEV. The vehicle you
describe would provide more than 3,400 meters/sec delta-v.
Apollo CSM only provided 2,804 m/s. Space shuttle orbiters,
on the other hand, only provide about 700 m/s. Soyuz TMA
provides about 390 m/s. Gemini only provided 98 m/s.

If CEV were to have the 7.5 metric ton dry mass you
describe, it would only have to weigh 12.63 tons or
so fully fueled to provide the same delta-v as space
shuttle - and only 10.1 tons to provide Soyuz-class
delta-v. A Medium-class EELV (with no strap-on
boosters) could handle these LEO missions, but it
*would* take a Heavy to do the trans-lunar CEV.

- Ed Kyle