From: SINCLAIR  DOUGLAS N <sinclai@ecf.toronto.edu>
Date: Thu, 4 Jan 1996 00:12:07 +0800
To: jimbell@pacifier.com (jim bell)
Subject: Re: Guerilla Internet Service Providers [NOISE]
In-Reply-To: <m0tXNaA-0008zSC@pacifier.com>
Message-ID: <96Jan3.102233edt.2052@cannon.ecf.toronto.edu>
MIME-Version: 1.0
Content-Type: text/plain


> As I understand the physics, the whole process could be made FAR FAR FAR
> more efficient if the rocket was boosted to about 40000 feet with a subsonic
> airplane, a' la' X-15 and such.  It's above 75% of the earth's atmosphere
> (dramatically reduced drag), is already going 600 mph in the correct
> direction, and is 8 miles closer to the  ultimate goal 250 miles up).  This
> might not sound like much of an advantage, but if you've ever worked out the
> mathematics of the Saturn V (or space shuttle, etc), the VAST majority of
> the fuel was used up in the first 20,000 feet, maybe even the first 5000
> feet.  It would be even better if the first stage could be an air-breathing
> supersonic ramjet, but that's not my field of expertise.

Cypherpunks isn't the right place to discuss this in detail, but...

Efficiency != Cheap
Kerosene is cheap.  Steel fuel tanks and rocket motors are quite cheap.
Making big dumb rockets is well understood.  However, aircraft integration
is not.  If you use an 'off-the-shelf' aircraft, it has a human in it.
That means the whole thing must be safe.  If you don't, you have a drone
aircraft which isn't cheap at all.  Remember, the cost of materials
scales linearly with size.  The cost of a complex system scales as the
square of the parts count.

These arguments are hashed out (admittedly without consensus) regularly
in the sci.space newsgroups.