Dholmes wrote:

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.

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

I believe it is impossible because the first stage of the Delta 4 is too large
to be launched by the first state of SeaLaunch. The Delta 4 is a larger
launch vehicle than SeaLaunch.

OK, I didn't look it up, but someone tell me if I am wrong.

Then I will say that trying to mate a full-scale LH2-LO2 large launch
vehicle with the SeaLaunch kerosene-LO2 first stage is a particularly
bad idea if you are going to take it by sea to the equator for each
launch.

Mike Walsh