Re: Re: starship-design: The Way ahead & Bugs

[KellySt@aol.com]

In a message dated 10/11/98 8:26:52 AM, ajcrowlx2@ozemail.com.au wrote:

>Hi Group
>
>KellySt@aol.com wrote:
>
>> In a message dated 10/8/98 8:45:51 AM, ajcrowlx2@ozemail.com.au wrote:
>>
>> >Hi Group,
>> >
>> >David Levine wrote:
>> >
>> >>  So, let's say the definition is simple: a manned
>> >> mission that travels to the very closest star system, Proxima Centauri,
>> >> within the working lifetime of the crew (i.e. they are physically
>> >> capable crew when the mission starts and when the mission arrives).  I
>> >> don't even care about the return trip just yet (we can get to that
>> >> next).  Will it be possible or not?
>> >>
>> >
>> >Possible, yes. Happening, probably not. I seriously doubt we'll be
launching
>> >Outer Planet missions by then, let alone interstellar flights. Some
Orbital
>> >Cities might be up and running, while Mars colonisation might be starting
to
>> >pick up leading to terraforming tests. I'm being pessimistic, but given
the
>> >current state of space who can blame me?
>>
>> A lot depends on local space industry, tourism being the biggy.  Space is
not
>> geting cheap enough technically so serious tourist and trans atmospheric
>> military missions are being considered.  If that drive enough of a market
to
>> drop costs to orbit down by a factor of few hundred (doable with current
>> tech), then far more expansive space ops get reasonable.
>
>Check out Cerulean Freight Forwarding Company for an idea of how cheap it
could
>get. They think they can build an orbiter for $1.5 million, and for ten times
more
>they think they can scale it up to a manned satellite launcher. Just uses
CH4/LOX
>but it just might happen. They have some other chemical engines that get Isp
~
>+600 s, but DoD wanted to slap a ban on their system - can't have the
neighbours
>getting such technology, can we?

These guys sound like BS artists.  Unless your talking airbreathing you don't
get 600s with chemistry.  Also the "someone baned our tech" conspiracy story
echos old urban myths of 100mpg carburators.

On the other hand their are some comercial reasearch programs that are
building and testing comercial launchers that could do similarly spectacular
cost improvements (space Access' ejector ramjet prototype for example) IF a
market was large enough to support and operation with enough scale to operate
a system that cost effective.  Market scale is vastly more important then
technology for low cost launch access.  Current normal tech could provide
launch services for less than 1/100th current costs with little difficulty.


>With CH4/LOX the price could drop to ~ $150/lb. Even lower with the super-
fuel
>mixes. Other possibilities include air-augmented rocket engines or advanced
>scramjets, either of which could get the price down to ~ $30/kg. Then space
would
>really happen...
>
>>
>>
>> Oh, personally - I'm real dubious about Mars colonization.  A chemically
toxic
>> planet with high rad and low G is not a great realestate value.
>
>Chemically toxic? You try living without CO2 for very long. Our lungs need it
just
>like they need O2 - we don't metabolise it, but it does play a role in
diffusion.
>As for the rest of Mars, AFAIK there's NOTHING toxic there that isn't found
roving
>about here. The soil isn't "super-oxidising" as some claim - that's
>thermodynamically and photochemically unlikely. Much of it is probably salty
or
>clayey.

That wasn't the final judgement of the analysis of the Viking data.  The said
the only explanation for the reactions with the soil samples would be a super-
oxidizing chemical reactino that breaks down organic molecules.



>> >I'd really like to see Stephen Baxter's Saturn mission. See his book
>> >"Titan". It'd be a great way to use all that 1960s and 70s tech that is
rusting
>>
>> >around the US.
>> >
>
>Would still like to see it happen. Could think of a better thing to do with
the
>Shuttles and the old Saturns.

Shuttles cant, Saturns are pretty much scrap metal.


>>
>>  Anti-matter would be great for Sol space travel in smallish
>> >quantities even. For IS flight, I'm not so sure.
>>
>> Big problem is holding the stuff stables for years in major quantities.
Also
>> I'm not sure if we could hold enough of it in a light enough tank.  I mean
it
>> would be silly to replace a thousand tons of fusion fuel for a quarter ton
of
>> anti-mater in a 3000 ton containment chamber.
>
>Come on! If we're gonna have fusion and mag-sails we'll need advanced
magnetic
>materials and field maintenance techniques - neural net control and high-Tc
>super-conductors. Else it's hopeless. With such antimatter will be easy!

  ?!   Fusion needs none of those.


>>
>> Also the radiation levels are real bad.
>
>Neutrinos are the big worry. Who knows how much damage they can do in
quantity
>-
>and no shielding stops them.

Neutrinos do virtually nothing.  Nutron radiation is bad.


>
>>
>>
>> Kelly
>>
>> >
>> >Pardon my ignorance but what's VASIMR?
>> >
>> >Adam
>
>Still asking guys!
>
>As for other bits of discussion I find it hard to imagine that alien
>biochemistries will be totally hostile/toxic and a real impediment to
>colonisation. Maybe. However toxins usually target certain hosts, and even
more
>so
>for pathogens. I think we take the "European diseases" analogy too far
because
>we're talking about disease transfer within a species on the one hand, and
disease
>transfer between different biochemistries on the other. Perhaps exobiological
>systems will use stereomolecules incompatible with ours, but beyond that I
doubt
>there'll be a lot of transfer. Molecular homologies do arise between widely
>different species, but these are yet to be documented as causing disease.
>
>If you want some idea of exobiological contact think of deep-sea fishing and
what
>they might dredge up. There's stuff in the deep that we've yet to encounter -
>weird microbes that we can't imagine - but we've been pulling up nets for
>centuries. Know of any pandemics from fish? From squid? No.

They are far less alien then stuff from another star system, and many of them
have proven very deadly.



>So I think the threat is overblown.
>
>Remember, Ebola's reservoir is monkeys [our relatives] not some wholly alien
>lifeform. And we are a lot closer to every lifeform on this planet than we
are
>to
>any exobiological entities.

Actually the best guess is Ebola lives in Bats.


>Adam


Kelly