[FPSPACE] Does heavy-lift make sense for the VSE?

[Chris Jones]

On Thursday 24 February 2005 09:32 pm, DwayneDay wrote:

> Boeing is currently pushing a version of the Delta IV-Heavy that would use
> six core vehicles clustered together.
>
> There are some reasons to be wary of this, however.  Delta IV-Heavy climbs
> very slowly, and it is actually scorched by its own exhaust.  In fact,
> portions of the vehicle even catch fire.  This makes for some dramatic
> photographs that make it look like the rocket is blowing up.  Can you
> really imagine that happening with six core vehicles--or a crew aboard?

Yeah, I'm not really thrilled with the whole Delta IV design, though it looks
cool.  I believe it is the only launch vehicle to use LH2 exclusively as a 
liftoff fuel (all other launchers which burn LH2 at liftoff have strapons
fuelled by something else, either solids, RP1 (kerosene) or some hydrazine
mixture).  Despite the high ISPs you get with LH2, its low density leads to
a large volume which results in large pumps and a relatively slow liftoff
speed, with the consequences you see on Delta IV.