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Re: Re: RE: starship-design: Interstellar mission within fifty years

Hi Group,
While we're on this stream...
-----Original Message-----
From: Zenon Kulpa <zkulpa@zmit1.ippt.gov.pl>
To: starship-design@lists.uoregon.edu <starship-design@lists.uoregon.edu>
Cc: zkulpa@zmit1.ippt.gov.pl <zkulpa@zmit1.ippt.gov.pl>
Date: Monday, 19 October 1998 23:32
Subject: Re: Re: RE: starship-design: Interstellar mission within fifty

>> From: KellySt@aol.com

>> Probably no real chance of
>> finding a planet with 1 g,
>Say, 0.6 to 1.5 g will be equally good.
>> right temp range, and non toxic but breathable air anyway.
>I am not asking for as much as air being breathable.
>Having a decent atmosfere has other advantages than breathing it:
>solar & cosmic radiation protection, no need for pressure suits
>(oxygen masks suffice - provided it is not toxic through
>skin contact: HCN or CS2 or the like are certainly rather bad,
>but methane, CO2, nitrogen, even little ammonia are bearable),
>lower temperature variation.
>-- Zenon
Not so long ago there was an "Analog" article on the range of bio-tolerances
for various poisons that we'd find unhealthy. I suspect that by the time we
launch starships bio-modifications will be fairly easy, so we'll be able to
take ammonia, CO, CO2, cyanide, sulphur compounds and so on at quite
elevated levels. None of those chemicals is going to be hugely abundant
anyway, since they're relatively odd finds in the 250 - 320 K range for
planets we'll be visiting. There's no guarantee that we'll find planets that
are exactly Earth-like, but then our current atmosphere is only a fairly
late state of affairs. For most of Earth's history there was a
whole lot more CO2, and a bit of ammonia and methane in the early days [if
Sagan is right.]

I think a planet is habitable if it has >100 torr atmosphere and a livable
temperature range [humans have gotten on in temperatures ranging between
190K and 335K with only a few prosthetics] and relatively easy water
supplies. Who needs oxygen when you can crack CO2?