Newsgroups: sci.space.shuttle
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: TITAN 4
Message-ID: <1989Jun21.164401.1295@utzoo.uucp>
Organization: U of Toronto Zoology
References: <4301.24986D0D@stjhmc.fidonet.org> <1989Jun19.192514.4696@utzoo.uucp> <3810@phri.UUCP>
Date: Wed, 21 Jun 89 16:44:01 GMT

In article <3810@phri.UUCP> roy@phri.UUCP (Roy Smith) writes:
>... just what the hell is so hard about building a big rocket?  You need a
>motor (or several), some fuel/oxidizer tanks, some plumbing to get the
>contents of the latter to the former, a stabilizer system, a big space to
>put the payload in, and maybe some stap-on solid boosters.

The trickiest parts are the motor -- getting stable combustion is not always
an easy business, and instabilities generally mean explosions -- and the
pumps.  The power output of a big rocket engine is measured in gigawatts,
in a package only a few feet across.  It doesn't take much of that energy
going in the wrong direction to make a heap big mess in a heap big hurry.
And pumping tons of sometimes-cryogenic-and-always-highly-reactive liquids
per second against high pressures is not a trivial problem either.  The
power output of the pump turbine on a single F-1 engine (the Saturn V
first stage had five) was 55,000 horsepower.

The biggest problem in reviving the Saturn V is that the engines are long
out of production.

>... I still don't see why the introduction of the
>Titan-4 is such a big deal...

Basically, it's not.  It's a slightly souped-up version of the assorted
Titan 3 variants, a little bigger and a little more powerful.  The biggest
problem was structural worries about the new larger payload shroud.

>	Question:  How much would it cost to build a new shuttle if you
>left out all the re-entry equipment (i.e. no wings, etc) and all the life
>support systems (i.e. no crew compartment) and used the space and weight
>saved to boost unmanned payloads as a non-reusable launcher? ...

What you've described is pretty much the same as either the Hughes/Boeing
Jarvis proposal or NASA's current Shuttle-C proposal.  It can certainly
be done.  It's not impossibly expensive, but it's not exactly cheap either,
especially with NASA doing it.

>Is it possible that this could ever
>compete with an expendable in terms of cost/payload-mass-lifted? ...

There is no fundamental reason why it couldn't; Jarvis was proposed as a
reasonably competitive big expendable.  Shuttle-C will not be economically
competitive, if it is built, because it will be built and launched by NASA;
its specialty will be getting unusually big payloads into orbit in one piece.
-- 
NASA is to spaceflight as the  |     Henry Spencer at U of Toronto Zoology
US government is to freedom.   | uunet!attcan!utzoo!henry henry@zoo.toronto.edu