# 12355 byhitssquad@... on March 21, 2012, 10:35 a.m.
Member since 2021-10-03
--- In spacesettlers@yahoogroups.com, sraj wrote:
> All rocket systems must use only Oxygen and Hydrogen.
> 4. Development of social systems suited for people living in an enclosed and limited space.
All societies are inherently space-limited, as well as limited in all other resources, in the near term. Social institutions such as markets and property-rights arose to efficiently allocate those inherently-limited resources:
http://www.juliansimon.com/writings/Ultimate_Resource
http://www.efficientfrontier.com/ef/404/bop2.htm
# 12356 byalglobus@... on March 22, 2012, 12:46 a.m.
Member since 2021-10-03
On Mar 21, 2012, at 3:35 AM, hitssquad wrote:
> --- In spacesettlers@yahoogroups.com, sraj wrote:
> > All rocket systems must use only Oxygen and Hydrogen.
>
> Hydrogen is a poor fuel to launch with. It gives little thrust,
> because of its low density.
>
Hydrogen/Oxygen rockets have the best ISP of any current launch
system. You can do a little better with Hydrogen/Flourine or Ozone,
but not much. Thus, H2/O2 is the bets rocket fuel. The reaction
mass is mostly water.
# 12357 byian.woollard@... on March 22, 2012, 2:42 p.m.
Member since 2021-10-03
On 22 March 2012 00:46, Al Globus wrote:
> system. You can do a little better with Hydrogen/Flourine or Ozone,
> but not much. Thus, H2/O2 is the bets rocket fuel.
>
Actually, no. The optimum for launch is a tripropellant system where the
mixture varies over the launch.
The reason is that hydrogen has poor density, so the tankage, pumps and
pipe mass is very high for any given thrust level; so you are better off
running with dense fuel early on, and then sliding across to hydrogen
towards the end when you've burnt off most of the mass and need less
thrust. The dry mass is lower.
And that's actually what the shuttle did, in effect, with the SRBs and
hydrogen fueled main engines. But it's also been shown to work with SSTO
systems, you gain about 30% bigger payload.
--
-Ian Woollard
# 12358 bybmaillists@... on March 22, 2012, 3:20 p.m.
Member since 2021-10-03
There is another consideration though. In this day and age the concerns
of the environmental lobby have to be taken into account - especially if
there is going to be a large number of launches per year - and for that
hydrogen is more likely to win them over, particularly if the hydrogen
is generated using renewable ground resources initially (you would hope
that later on power from SPS would be used).
On 23/03/2012 01:42, Ian Woollard wrote:
# 12359 byian.woollard@... on March 22, 2012, 3:42 p.m.
Member since 2021-10-03
That's a laugh, industrially, hydrogen is made using steam reforming of
methane and generates tonnes of CO2, and any way you cut it, making liquid
hydrogen is highly energy intensive.
right now at the very least, much more environmentally friendly than
hydrogen.
On 22 March 2012 15:20, b wrote:
> There is another consideration though. In this day and age the concerns
> of the environmental lobby have to be taken into account - especially if
> there is going to be a large number of launches per year - and for that
> hydrogen is more likely to win them over, particularly if the hydrogen is
> generated using renewable ground resources initially (you would hope that
> later on power from SPS would be used).
>
> B
>
--
-Ian Woollard
# 12360 bysraj99@... on March 22, 2012, 6:33 p.m.
Member since 2021-10-03
Ian Woollard wrote:
right now at the very least, much more environmentally friendly than
hydrogen.
....................
Point noted.
What about compacted wood or straw? or hard coconut shell? Would these also
score over hydrogen?
Regards,
Selvaraj
On 22 March 2012 21:12, Ian Woollard wrote:
# 12361 byvictors@... on March 22, 2012, 7:56 p.m.
Member since 2021-10-03
how do they compare, pricewise and thrustwise?
Sent: Thursday, March 22, 2012 10:42 AM
To: b
Cc: spacesettlers@yahoogroups.com
Subject: Re: [spacesettlers] Resources are inherently limited, near term (was The three challenges)
That's a laugh, industrially, hydrogen is made using steam reforming of
methane and generates tonnes of CO2, and any way you cut it, making liquid
hydrogen is highly energy intensive.
Rockets can be made to run just fine on biofuels though. Biofuels are,
right now at the very least, much more environmentally friendly than
hydrogen.
On 22 March 2012 15:20, b wrote:
> There is another consideration though. In this day and age the concerns
> of the environmental lobby have to be taken into account - especially if
> there is going to be a large number of launches per year - and for that
> hydrogen is more likely to win them over, particularly if the hydrogen is
> generated using renewable ground resources initially (you would hope that
> later on power from SPS would be used).
>
> B
>
--
-Ian Woollard
# 12362 bymikecombs@... on March 22, 2012, 8:37 p.m.
Member since 2021-10-03
> or hard coconut shell?
Regards,
Mike Combs
From: spacesettlers@yahoogroups.com [mailto:spacesettlers@yahoogroups.com] On Behalf Of sraj
Sent: Thursday, March 22, 2012 1:33 PM
To: spacesettlers@yahoogroups.com
Subject: Re: [spacesettlers] Resources are inherently limited, near term (was The three challenges)
Ian Woollard wrote:
Rockets can be made to run just fine on biofuels though. Biofuels are,
right now at the very least, much more environmentally friendly than
hydrogen.
....................
Point noted.
What about compacted wood or straw? or hard coconut shell? Would these also
score over hydrogen?
Regards,
Selvaraj
# 12363 bybmaillists@... on March 22, 2012, 10:36 p.m.
Member since 2021-10-03
True, but it doesn't have to be though. You could use wind farms or
solar power to make the hydrogen which might make it an easier sell.
B
To:"b"
Cc:
Sent:Thu, 22 Mar 2012 15:42:41 +0000
Subject:Re: [spacesettlers] Resources are inherently limited, near
term (was The three challenges)
That's a laugh, industrially, hydrogen is made using steam reforming
of
methane and generates tonnes of CO2, and any way you cut it, making
liquid
hydrogen is highly energy intensive.
Rockets can be made to run just fine on biofuels though. Biofuels
are,
right now at the very least, much more environmentally friendly than
hydrogen.
On 22 March 2012 15:20, b wrote:
> There is another consideration though. In this day and age the
concerns
> of the environmental lobby have to be taken into account -
especially if
> there is going to be a large number of launches per year - and for
that
> hydrogen is more likely to win them over, particularly if the
hydrogen is
> generated using renewable ground resources initially (you would
hope that
> later on power from SPS would be used).
>
> B
>
--
-Ian Woollard
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# 12364 byalglobus@... on March 24, 2012, 4:59 p.m.
Member since 2021-10-03
On Mar 22, 2012, at 8:42 AM, Ian Woollard wrote:
> of
> methane and generates tonnes of CO2, and any way you cut it, making
> liquid
> hydrogen is highly energy intensive.
>
This, of course, is set in stone and cannot possibly be changed or
improved in any way.
# 12365 byian.woollard@... on March 25, 2012, 3:14 p.m.
Member since 2021-10-03
On 22 March 2012 19:56, Victor Smith wrote:
>
If you pick the right biofuel, it should be about the same as kerosene,
cost-wise and for specific impulse. Give or take 10-20% or so (hydrogen is
about a factor of ten more expensive).
-Ian Woollard