Re: starship-design: The Way ahead & Bugs

[Amanda & Adam Crowl <ajcrowlx2@ozemail.com.au>]

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?

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.

>
>
> >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.

>
>  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!

>
>
> 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.

>
>
> 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.

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.

Adam