"Dholmes" wrote in
:

While doing research on competing rockets I had this crazy idea:

If you take the first stage of SeaLaunch and then use the first stage
of a
Delta 4 as a second stage you have a rocket that can launch (based on
my quick calculations) over 60,000 lbs to LEO.
About the same 60,000 lbs to GTO if the Delta 4 second stage is used
as a third stage.
That would dwarf any other rocket on the maket today with no new
technology.

Two Zenit first stages in parallel with a Delta IV second stage ignited
at altitude would be a hellava launch vehicle.

Does any one know how hard it would be to do and if there would be any
market?

Sea Launch would need extensive redesign to handle a much larger vehicle
and install liquid hydrogen facilities. I don't think it's feasible.

New launch pad/facilities. Alas, no market at present.

I'd rather focus on a Delta IV with reusable liquid boosters, or a major
upgrade to a cryogenic second stage on Zenit and Delta IV second stage
as the third stage.

When there's a mission requiring heavy-lift/high energy, as in a manned
return to the Moon, we'll certainly see more serious proposals along these
lines.

--Damon