message 0156

• Speculations on spaceship (esp. Rider) drive and fuel

>Date: Tue, 1 Jun 93 11:50:35 +0200
>From: mst@vexpert.dbai.tuwien.ac.at (Markus Stumptner)
>Subject: Cherryhlist

Onno Meyer wrote:
>I wrote:
>> Given that we know next to nothing about how the FTL drives 
>> are supposed to work, this is as valid a reason as any. Do riders 
>> have vanes, btw?   

>Do you think FTL- and STL-engines are the same hardware operating in
>different modes, or what does that mean?

Yes, that was what I proposed.

>I always assumed that carriers have rocket-engines and jump-engines,
>while the riders have only rocket-engines.

Whatever they're using, it's certainly not rocket engines.   You need
huge amounts of reaction mass to maneuver at high g's with rocket
engines.  This would either make the riders the size of a Saturn V
or it would make them sitting ducks, in terms of the accelerations
carriers (and therefore any weapon intended for attacking carriers)
can tolerate.  Therefore, since they need a "magic" drive as badly 
as the carriers, it could well be a minor version of that used by 
the carriers. 

I also recall several instances of riders being described as guarding
the outskirts of a system, which again implies accelerations unachievable
with rocket drives unless you have access to significant amounts of reaction
mass.  Otherwise it would have taken them months to get there.

>- In _Hellburner_, the craft lost an significant part of it's mass
>  in an instant because it fired and moved. The powerplant would 
>  consume it's fuel in a more steady manner.

I haven't read "Hellburner", but does "craft" refer to a rider ship here,
or to another vessel?  The non-military ships in "Heavy Time" all use 
conventional rocket engines (and note that they also get a large part
of their acceleration from the stations' beams).

>  Further more, the _Legacy_ aquired speed in a gentle _burn_ due to
>  it's passenger, and that sounds like a "conventional" rocket.

I would rate that as a colloquialism.

>- Why introduce another "magic" technology without compelling reason?

I did not introduce any, I used the one already in place.  The compelling
reason, unfortunately, *is* there, given the performance of the ships
that Cherryh describes.

>  Jumpdrive was necessary to mace interstellar stories possible, and
>  tape-teaching was necessary to colonize Cyteen. All the plots work
>  with "conventional" rockets.

The plots would, in general, but not the descriptions given of insystem
maneuvering.

>A carrier may "shed its riders, which will travel at that speed". 
>I read from this that a ridership is not capable of the major
>speed/vector changes done with the FTL-engines.
>Of course, this interpretation is not supported by the remainder of
>the text (the notes about rider movement).

Exactly.  In such a case I would prefer to dismiss that single line of the
text (which I suppose is taken from the game supplement), especially since
it would severely limit the utility of riders in combat (see above comments).

	Markus