[extropy-chat] Re: NASA going back to the moon

Tue Sep 20 19:14:44 UTC 2005

I wouldn't explicitly call the entire program "Apollo style". The CEV
launcher is a five segment shuttle SRB as a reusable first stage. The
second stage seems to be of similar performance to the S-IVb stage of
the Saturn program. This would lift up to 40,000 lbs into orbit, which
is about the same capacity of the space shuttle today, would be more
than ten times safer than the shuttle, and cheaper to operate despite
the throw away of the upper stage and the CEV service module (if these
are put on a significant assembly line, the costs would come down
further).

The heavy lift booster uses two 5 segment srbs and a lengthened shuttle
tank, with 5 SSMEs underneath and cargo section above. Outside of the
SRBs, the rest of it seems to be a throw-away. A use-once may seem more
expensive, but the fact is that this way is cheaper than using the
space shuttle, which is possible the biggest boondoggle of the entire
space program history. Using the SSMEs once (on the shuttle they are
essentially rebuilt entirely after each mission) would allow them to be
operated at higher thrust and Isp, given there is no concern about long
term metal fatigue. Different configurations could lift up to 170k-190k
lbs, which is in the range of the Saturn V, though simpler and
partially reusable.

The only reasons for having such large lift capacity is to lift large
space station modules, moonbase modules, segments of a Mars mission,
possibly reels of skyhook ribbon tether, as well as
anti-asteroid/comet/ICBM capability. It is clear from the plan I've
read that the intent is for this program to set up a moon base for
production of fuel for Mars missions. With such a foot-hold, I would
not be surprised if some other industry initiatives result in
refinement of lunar ores and other resources for other application
spin-offs. It remains to be seen whether the Dems succeed in killing
the program infrastructure this time just like they did in the 70's.

While the US space movement tends to have a fixation on winged vehicles
as the definition of 'progress', I think the shuttle has clearly
demonstrated that we don't have the technology yet to produce winged
aerospace vehicles that are sufficiently safe for human use AND capable
of being operated in a manner similar to airline standards and cost
regimes. This will not always be the case. Right now, though, this is
tried and true. The disparity in safety record between the Shuttle and
Soyuz programs clearly demonstrate the fact that capsule type
configurations are safer, easier. I predict that NASA will always
suffer such incompetency, and the first current-technology winged
vehicle we see in operation reliably will be privately launched.

The GTX program that NASA is involved in, a follow on to the Hyper-X
program, will clearly be demonstrating an integrated, functional,
air-breathing hypersonic orbital launcher with rocket based combined
cycle engines some time around 2008-2010. If the test program succeeds,
it will be around the 2015-2020 time frame before this technology is
available for launching payloads, however it is clear to me that NASA
needs to get away from its absurd fixation upon very low density LH2
fueling of a vehicle in which aerodynamic cross section and vehicle
volume are of utmost importance, requirements which mandate against low
density fuels. If they stick with this fuel, I predict that the GTX
program will fail and we will not see combined cycle launch technology
for at least another generation.

The GTX program itself is looking to build a 260k lb vehicle capable of
putting a measely 300-600 lbs of cargo in orbit as its reference design
(the first vehicle will be a scaled version to test its ram and scram
systems). A cargo capacity of this sort can very easily be entirely
eaten up by vehicle development weight gains that ALWAYS happen. This
cargo capacity is pathetic and being eaten up by overlarge LH2 tankage
and the resultant excessive aerodynamic drag and gravitational losses. 

One paper I've found
(http://www.dunnspace.com/alternate_ssto_propellants.htm)
shows that an SSTO fueled by, say, cyclopropane or other dense high
performance fuels like UDMH, propargyl alcohol, or methylacetylene,
would put up to two and a half times more cargo than LH2 for the same
tank volume, or the same amount of cargo with a smaller, cheaper
vehicle (and this is entirely ignoring using fuels or oxidizers
utilizing fluorine or chlorine in them, or diborane/pentaborane, which
offer significant Isp gains but are also toxic until burned).

My feeling that NASA is absurdly fixated on LH2 is borne out by the
fact that they quickly cancelled the X-43B follow on to the Hyper-X A
model, which would have tested other hydrocarbon fuels against LH2 in
head to head real flight test conditions. The paper I referenced above
was suppressed from publication at the behest of NASA as well and only
gained exposure at Space Access 96.

Particularly methylacetylene, which is commonly available as welders
MAPP gas, is relatively cheap at $4/kg or so. In refined form should be
around $10/kg. These prices are entirely comparative to the prices for
LH2 in bulk (while the above prices are retail prices for small
quanitities), so the argument that flight operations with LH2 would be
cheaper are wrong, especially when you consider that, liter for liter,
the methylacetylene can lift more cargo, thus more revinue dollars per
kg of fuel burned. Given that LH2 is an extreme cryogenic, while
methylacetylene has a boiling point of 270 K, the operational costs of
working with LH2 will be much higher.

Generating LH2 consumes fossil fuels in the energy infrastructure (both
in electrolysis or refinement from NG, as well as liquification), so
claiming that LH2 is the clean fuel is also baseless. You are going to
pollute one way or the other, LH2 is only slightly cleaner. Even if
these alternate fuels are more polluting, you want to concentrate your
pollution on economic applications which were very high value, like
space launches, leaving the low pollution fuels to low value economic
applications, like daily commuting.

--- Elaine Walker <elaine at ziaspace.com> wrote:

> Hi all,
> 
> It thought I'd contribute some information about the pro-space
> community's 
> reaction to NASA's back-to-the-moon plans.
> 
> There are very mixed feelings within the pro-space community about
> NASA's 
> back-to-the-moon plans which were just announced. I'm still trying to
> 
> decide where I stand, personally. I tend to agree with SAS's
> arguments for 
> why Apollo style is the wrong way to go, however, I want NASA to
> succeed 
> with this one! It's incredible that NASA has this opportunity! I hope
> they 
> don't muck it up or come up with a dead-end plan. If they don't 
> incorporate enough infrastructure (ie. if they build big apollo
> rockets 
> that are thrown away each time) and don't incorporate any orbital
> assembly 
> into the plan (which they'll need if they want to, say, go to Mars 
> eventually!), this could be a dead end. This plan was just released
> and it 
> may change. It probably won't change much though. Radical changes
> within 
> NASA would have to occur - people would have to be fired, entire NASA
> 
> offices closed, a mature bureacracy reworked from the inside out - in
> 
> order to do it the RIGHT way. So maybe it's the wrong way or no way
> at 
> all. I'd be interested in your opinions!
> 
> 
> The Space Access Society's most recent update has some good arguments
> for 
> why it's a BAD idea for NASA to do it Apollo style. (The Space Access
> 
> Society's sole purpose is to promote radical reductions
> in the cost of reaching space.)
> 
>       http://www.space-access.org/updates/sau112.html
> 
> 
> The National Space Society supports the plan. (NSS has a reputation
> for 
> being NASA's cheerleaders. Although they have tried hard to get away
> from 
> that stereotype in the last few years, they seem to be cheering for
> NASA 
> at the moment.)
> 
>       http://nss.org/news/releases/pr20050919.html
> 
> 
> I'm not sure yet what the official stance of the Space Frontier
> Foundation 
> is, but I assume it will be somewhere in between... A press release
> will 
> probably pop up soon here:
> 
>       http://www.spacefrontierfoundation.org
> 
> 
> Just a heads up... When all is said and done, the Space Access
> Society is 
> usually RIGHT - usually the ones to say "We told you so". I've notice
> that 
> with just about every pro-space issue. That scares me in this case
> because 
> I really want NASA to succeed with this one!
> 
> 
> -Elaine
> 
> ----------------------
> Elaine Walker
> elaine at ziaspace.com
> 
> Mars Projects Manager and Advocate
> Space Frontier Foundation
> http://www.mars-frontier.org
> http://www.spacefrontierfoundation.org
> 
> Region 8 Chapters Organizer
> National Space Society
> http://www.nss.org
> 
> U.S. Groups Team Leader
> Space Program Advisor
> Extropy Institute
> http://www.extropy.org
> 
> Pro-Space-Pop Music
> http://www.ziaspace.com/ZIA
> _______________________________________________
> extropy-chat mailing list
> extropy-chat at lists.extropy.org
> http://lists.extropy.org/mailman/listinfo/extropy-chat
> 

Mike Lorrey
Vice-Chair, 2nd District, Libertarian Party of NH
Founder, Constitution Park Foundation:
http://constitutionpark.blogspot.com
Personal/political blog: http://intlib.blogspot.com

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