A thought about how one could use the temperature differential

between sunside and nightside on a spacecraft.



If an external sunside heat collector contained a volatile liquid

that could be superheated to pass into a turbine generator in the

bowels of the craft, and the output cooled by radiators on the

nightside, power could still be generated if the solar panels had to

be furled during a solar flare episode.



Or am I missing something here?





Jan

Ueli, Jim,



That's OK then! Was just looking for a suitable backup system.



By the way, I am uncovering more and more electrothermal-powered

missions, the latest being NASA's Lunar Reconnaissance Orbiter.



http://www.nasa.gov/mission_pages/LRO/main/index.html



http://lro.gsfc.nasa.gov/



http://lcross.arc.nasa.gov/resources/LaunchPreview.ppt



http://www.nasa.gov/pdf/360020main_LRO_LCROSS_presskit2.pdf







  From the press-kit, I garner these stats for the Orbiter itself

(excluding primary launch vehicle's fuel and mass etc):



Solar Array Area: 13.68 sq/m



Solar Array Output:  685 watts



Watts/Square Meter = 50



Orbiter Mass:  1018 kg



Fuel Mass:  898 Kg



Mass Ratio:   Fuel/Orbiter = 1:1.3



NASA's figures for the cost of water transported to the Moon $50,000/

pound (about $23,000/Kg), clearly another market here.







NASA seem very cagey about the precise details of the ion-drives.

This mission was also launched on Russian-made rocket motors.





Jan











On 29 Jun 2009, at 16:37, Ueli Scheuermeier wrote:



> Jan, as far as I understand you've just reinvented the "solar

> dynamic" electricity source.

>

> Ueli

>

> --- On Mon, 6/29/09, EOS Mars

> Program<eos.mars.program@...> wrote:

>

> From: EOS Mars Program <eos.mars.program@...>

> Subject: [NEAmines] Heat Differentials

> To: NEAmines@yahoogroups.com

> Date: Monday, June 29, 2009, 3:28 PM

>

> A thought about how one could use the temperature differential

> between sunside and nightside on a spacecraft.

>

> If an external sunside heat collector contained a volatile liquid

> that could be superheated to pass into a turbine generator in the

> bowels of the craft, and the output cooled by radiators on the

> nightside, power could still be generated if the solar panels had to

> be furled during a solar flare episode.

>

> Or am I missing something here?

>

> Jan

My apologies, Jim, you are absolutely correct! No excuses for the

dismal conversion.



This is why NASA probes keep hitting what they shouldn't, by not

converting European instruments' measures into US.



NASA recently begged off converting all its activities to metric for

global compatibility in space, as they say it would cost too much,

but the cost cited amounted to about the price of the Mars lander

that had a metric radar altimeter, and US software, with no chance of

ever finding ground level on that planet.



However, ignoring my obvious folly for the moment, this looks even

better for selling water to the Moon, UNLESS of course the LRO does

find ice deposits in the Polar craters...........



GO METRIC NASA!





Jan







On 30 Jun 2009, at 11:29, james brown wrote:



> Most ion drives do not spend much power on heating, Just enough to

> ionize it, but mostly it uses extrema charges to accelerate the

> gas. The MET uses electricity to supper heat a gas way beyond what

> can be done chemically, but it keeps it just below ionizing.

>

> A Kg = 2.2 pounds. Your Moon water cost do not make sense, $50,000/

> # would work out to $110,000/Kg not 23,000/Kg.

>

> Jim Brown

>

> From: EOS Mars Program <eos.mars.program@...>

> To: NEAmines@yahoogroups.com

> Sent: Monday, June 29, 2009 1:04:41 PM

> Subject: Re: [NEAmines] Heat Differentials and more

>

> Ueli, Jim,

>

> That's OK then! Was just looking for a suitable backup system.

>

> By the way, I am uncovering more and more electrothermal- powered

> missions, the latest being NASA's Lunar Reconnaissance Orbiter.

>

> http://www.nasa. gov/mission_ pages/LRO/ main/index. html

>

> http://lro.gsfc. nasa.gov/

>

> http://lcross. arc.nasa. gov/resources/ LaunchPreview. ppt

>

> http://www.nasa. gov/pdf/360020ma in_LRO_LCROSS_ presskit2. pdf

>

> From the press-kit, I garner these stats for the Orbiter itself

> (excluding primary launch vehicle's fuel and mass etc):

>

> Solar Array Area: 13.68 sq/m

>

> Solar Array Output: 685 watts

>

> Watts/Square Meter = 50

>

> Orbiter Mass: 1018 kg

>

> Fuel Mass: 898 Kg

>

> Mass Ratio: Fuel/Orbiter = 1:1.3

>

> NASA's figures for the cost of water transported to the Moon $50,000/

> pound (about $23,000/Kg), clearly another market here.

>

> NASA seem very cagey about the precise details of the ion-drives.

> This mission was also launched on Russian-made rocket motors.

>

> Jan

>

> On 29 Jun 2009, at 16:37, Ueli Scheuermeier wrote:

>

> > Jan, as far as I understand you've just reinvented the "solar

> > dynamic" electricity source.

> >

> > Ueli

> >

> > --- On Mon, 6/29/09, EOS Mars

> > Program<eos.mars.program@ btinternet. com> wrote:

> >

> > From: EOS Mars Program <eos.mars.program@ btinternet. com>

> > Subject: [NEAmines] Heat Differentials

> > To: NEAmines@yahoogroup s.com

> > Date: Monday, June 29, 2009, 3:28 PM

> >

> > A thought about how one could use the temperature differential

> > between sunside and nightside on a spacecraft.

> >

> > If an external sunside heat collector contained a volatile liquid

> > that could be superheated to pass into a turbine generator in the

> > bowels of the craft, and the output cooled by radiators on the

> > nightside, power could still be generated if the solar panels had to

> > be furled during a solar flare episode.

> >

> > Or am I missing something here?

> >

> > Jan

Some interesting background context to the metrication issues:



http://www.space.com/news/metric_policy_100199.html



http://edition.cnn.com/TECH/space/9909/30/mars.metric/



http://oig.nasa.gov/old/inspections_assessments/g-00-021.pdf



http://science.nasa.gov/headlines/y2007/08jan_metricMoon.html



http://www.metrication.us/content/nasa-criticised-sticking-imperial-

units





Jan









On 1 Jul 2009, at 07:02, james brown wrote:



> NASA has a much better record on hitting Mars than anyone else.

> That misstake has only once happened. That is not their problem. I

> think they should make the change, but that is an different issue.

>

>

> Earth water and almost anthing else to LEO will get much cheaper.

> Starting with SpaceX, but then even much better when we have

> implemented the tether upper stage. After talking to Elon Musk it

> looks like he expcet that to be in a few nundred dollars per pound.

> The tether should lower to ten percent that. Since the cost of

> asteroid water even then will depent on cost to LEO it will still

> be a good money maker at fifty dollars a pound or less.

>

> Jim Brown

Ueli,



Yes, I am clear on this one, and I think we need to label them

differently.



The point I was making on the stats, is how efficient these electric

drive mass ratios are in themselves, even without the higher output

of MET's (although these need more solar array area, the power per

sq. metre on current PVs seems good for these purposes).





Jan





On 1 Jul 2009, at 07:19, Ueli Scheuermeier wrote:



> Yes, as far as I figure, we need to differentiate electric drives

> (such as ion engines) from electrothermal drives, such as METs. Big

> difference, I believe.

>

> Ueli