Re: Re: starship-design: What is safest?

[Kelly St <KellySt@aol.com>]

In a message dated 12/29/97 10:35:00 AM, TLG.van.der.Linden@tip.nl wrote:

>Kelly wrote:
>
>>>What military system HAS to work? Virtually all systems have backups of
some
>>>kind. While the backup is being used, the primary system can be repaired or
>>>replaced with all the outside help that may be needed.
>>>In case of field equipment where no direct outside help is available there
>>>too are many (although less efficient) backups available. It would not be
>>>very smart to bet on one single system during a fight, no matter how well
>>>designed.
>>
>>To a degree ALL important systems are dedsigned that way.  You always make
>>sure the failure of one system would not shut everything down, or at least
not
>>shut it down catostrophicly.  But that not always practical.  Rip one of the
4
>>tires of a truck or car, and the vehical is stuck until fixed. Since
Military
>>equipment is usually operated in as bad a situation as we can find (war) and
>>put to the most adverse conditions the enimy can find, and operated away
from
>>suply and sevicing bases, its has to be very tough.  Just like exploration
>>equipment.
>
>It has to be tough, but not into extremes, since backups are available or
>will be shortly. I'd guess that if military cars had to be made more
>reliable, they should not use air-pressured tires. Chances of a car getting
>stranded by a punctured tire on rough terrain seem to be rather high.
>BTW Many succesful explorers from the past used equipment that they could
>repair or rebuild themselves without outside help. Several expedition
>leaders designed equipment with that criteriom themselves before they went
>exploring.

True but unlike explorers of the past, interstellar explorers would be able to
carru enough to fix things that are as sophisticated as they need.  We'ld
probably need to accept that the exploration gear will only last a few years,
archive the data, and make the ship systemsm durable enough to get back.

>>>When parallel computing is made to work, then making computers more robust
>>>is supposed to be easy. Furhermore superconducting magnets are great to
>>>avoid mechanical wear. (I'd suggest you'd use these on your hab train.)
>>>Also shielding equipment from a normal moist, temparture fluctuating, dusty
>>>environment increases lifetime significantly.
>>
>>Shadow processors are used even now to keep a hot back up, or verification
>>systems, on-line.  But sooner or later the computers will fail, and after
>>comparativly short service lives.
>
>While some applications may ask for highgrad computing power, many don't
>need to. In much electric equipment limits are pushed, something that we
>certainly can't trust to do in our starship.
>So we should make circuits/chips that have the computing power of x years
>back but use the much more precise and reliable technology of today.

Given that even 10 year old circuts are generally a 100 times less capable
then current systems, that might not be acceptable.  Also its not clear that
old design IC's built with new equipment would last especially longer then
current designs built on the same equipment.

>Similar to what Zenon wrote, we shouldn't expect the same luxuries as in our
>homes.

The ship is a high tech exploration system.  Computing power isn't a luxury.
Any cut in computer sophistication will be a direct impact in the ability of
the science teams on the ship to analiae the data the surveyteams on the
ground, and the probes, recover.


>>>"Simple" structural loads? While the exhaust of a rocket engine looks crude
>>>and simple, the complete engine consists much more than that. I wonder if
>>>the fusion engines make the design simpler. That little bit of corrosion
you
>>>talked about may very well affect reflectivity/conductivity that will
>>>escalate the corrosion within seconds (or less).
>>
>>The fusion engines are far simpler then standard rocket engines.  I.E. few
>>pumps, nozzels, no presure vessels, etc.  I'm not clear what you mean about
>>reflectivity/conductivity.  Certainly a system with the scale your talking
>>about wouldn't have its conductivity effected by surface blemishes.  If its
a
>>problem, design the system so it will work with the entire surface corroded
or
>>clean.
>
>If a fusion engine is so simple, then a fusion power plants should not be to
>hard to build and maintain either. What I've seen from fusion power designs
>is that they look pretty complex, more complex than chemical rocket engines.

Power plants would need to be a little more complicated since they need to
convert reactor power to electric powe.  Also the current designs (ignoring
the magnetic tourus systems which are pretty unusable) arn't that complicated.
Even better most of their components are large blocks of materials (lenses and
photo multipliers for laser fusion, thick conductor bands for magnetic and
electrostatis control systems, heavy metal support structure, etc.).  Compared
to a computer core their trivial.


>>>If an engine part fails, disasterous things will happen. If a circuitboard
>>>fails, it likely can be repaired before lifetreathening situations arise.
>>
>>That depends un what the circut board controls.  Circut failures can and do
>>kill people rapidly.
>
>I don't know what kind of circuit failure you mean.

Anything that could disrupt the function of the circut.  (Corosion shorting
out pathways, capacitors starting to leak, diodes breaking down and not
filtering the electron flows, IC chips logic burning out, etc.)


>Tim

Kelly