Chris Adams wrote:
> Once upon a time, Andrew Swallow   said:
>> Two different design of rockets for the same mission appears expensive. 
> 
> They aren't two different designs for the same mission.  First, there
> are a number of shared pieces between the designs.  Second, the missions
> are different.

They were the same mission the last time I looked - going to the moon.
The cargoes were different.

> 
> Ares I is the people lifter.  It will carry a capsule to low Earth
> orbit, which can then do multiple things.  It can reach ISS (since the
> Shuttle is going away, this will be our way to get people to and from
> the station).  It can also dock with other vehicles to go other places
> (the Moon for now, hopefully Mars later).
> 
> Ares V is the heavy lifter.  It will put unmanned vehicles (or parts of
> vehicles) in orbit.  If it takes more than one launch to get the
> necessary vehicle in orbit, the people just wait for all the pieces to
> reach orbit and then ride up on an Ares I.
> 
>> Alternately could NASA come up with its own rocket to launch the lot?
> 
> That was essentially what we did in the 1960s with the Saturn V and then
> in the 1970s with the Shuttle - try to make one vehicle that can do
> everything.  That doesn't work very well.
> 
> NASA is now trying to build a Honda Civic to carry people and a MAC
> truck to carry hardware.  They'll share some design pieces, but they are
> different vehicles.  What you are suggesting is instead trying to use a
> Ford Expedition to do everything, but it pretty much sucks at all jobs
> (can't carry as much hardware and is rather inefficient at carrying
> people).
> 
And gets to the moon a couple of years earlier and at a lot cheaper price.

The big delay is developing the Area_I.  By the time NASA goes back to 
the moon there will be 3 rockets that can lift the people.  This is an 
invitation to get things cancelled.
http://www.directlauncher.com>

Andrew Swallow

> This is actually one of the proposals for the original Moon mission:
> build a people lifter and a heavy lifter.  You launch the heavy lifter
> (possibly multiple times) to get a long-range vehicle in orbit, then
> launch the people to take a ride.  That's probably the best way for
> long-term use, but there were too many unknowns in the 1960s with
> docking that could have caused the US to fall behind and miss the
> deadline (fully automated docking is still a challenge).
>
--- SBBSecho 2.12-Win32