A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Space Science » Technology
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

Technologies for Moon mission useable for missions further out



 
 
Thread Tools Display Modes
  #41  
Old July 2nd 10, 04:51 AM posted to sci.space.tech
Niels Jørgen Kruse
external usenet poster
 
Posts: 49
Default Technologies for Moon mission useable for missions further out

Steve Willner wrote:

Michael Turner writes:
Since you're going to need electricity for many other purposes anyway,
I like the idea of using LEDs in both lunar and martian
agriculture.


Notice that the electricity you have to supply to the LEDs, depending
on assumptions, is more than you would have to supply to heaters.
Take a look at Fig 9 in the Hublitz et al. paper.


You need something other than solar panels to supply electricity for
heaters at night. Turning off lights at night on the other hand is OK.

--
Mvh./Regards, Niels Jørgen Kruse, Vanløse, Denmark

  #42  
Old July 2nd 10, 04:51 AM posted to sci.space.tech
Michael Turner[_2_]
external usenet poster
 
Posts: 27
Default Technologies for Moon mission useable for missions further out

On Jul 1, 10:36 am, (Steve Willner) wrote:
.... They seem to
be assuming a perfect emitter and a factor of 2.25 for the ratio of
radiating surface to greenhouse area. These strike me as very
conservative assumptions.


Perhaps they are trying to compensate somehow for their apparent
assumption of agriculture only in mid-summer?

Since you're going to need electricity for many other purposes anyway,
I like the idea of using LEDs in both lunar and martian
agriculture.


Notice that the electricity you have to supply to the LEDs, depending
on assumptions, is more than you would have to supply to heaters.
Take a look at Fig 9 in the Hublitz et al. paper.


Which shows not electricity specifically, but heat gain. And not from
LED illumination, but from incandescent lamps. Apples and oranges
comparison. What I thought we were now talking about is a system
where most heat is supplied separately from illumination. Fig. 9
suggests to me that you might as well separate the two functions. It
also suggests to me that, as long the simplest and most manageable
design is an opaque insulating shell over your plants, you might as
well simplify further and locate agriculture in a lava tube, not on
the surface. Solar storm particles would drill right through that
insulating layer and (probably) kill your plants, unless the shell is
covered with very thick pile of Martian regolith. Well, nature might
have prefabricated such shielding: cave ceilings. Why waste it?

-michael turner

  #43  
Old July 3rd 10, 02:21 PM posted to sci.space.tech
Hop
external usenet poster
 
Posts: 29
Default Technologies for Moon mission useable for missions further out

On Jun 27, 7:12 am, Michael Turner
wrote:

Both are problematic for water supply, but Mars has ice caps, at
least. The Moon? Over the long run, the cheapest place from which to
fetch water for a lunar base might actually end up being Phobos, ...


That was my opinion until a few months ago.

Recently Chandrayaan 1's mini-SAR radar seems to indicate thick ice
sheets at the lunar poles.
http://blogs.airspacemag.com/moon/20...e-of-the-moon/
http://www.nasa.gov/mission_pages/Mi..._deposits.html

And LRO has recently given additional confirmation. This article was
posted July 1, 2010:
http://www.onorbit.com/node/2335

600 million tons at each pole. Sheets 2 or more meters thick.

  #44  
Old July 3rd 10, 02:21 PM posted to sci.space.tech
Hop
external usenet poster
 
Posts: 29
Default Technologies for Moon mission useable for missions further out

On Jun 28, 7:31 pm, Alain Fournier wrote:

Phobos is still quite deep in the Martian gravity well. Why not go
get it in the main asteroid belt?


Surprisingly, being in Mars' gravity well makes Phobos and Deimos more
accessible, not less.

From LEO, trans Mars insertion is about 3.6 km/sec.


On arrival at a 300 km altitude Martian periapsis, a 1.4 km/sec burn
suffices to change the hyperbola into an ellipse with a 5981 km
altitude apoapsis.

When this ellipse reaches apoapsis, a .6 km/sec burn will circularize
the orbit.

So from LEO to Phobos takes about 5.6 km/sec delta V.

LEO to a main belt asteroid takes in the neighborhood of 8 to 10 km/
sec delta V. Could take a lot more if the orbit has a good inclination
(as a lot of asteroid orbits do).


  #45  
Old July 6th 10, 02:08 AM posted to sci.space.tech
Michael Turner[_2_]
external usenet poster
 
Posts: 27
Default Technologies for Moon mission useable for missions further out

On Jul 2, 12:51 pm, Alain Fournier wrote:
Michael Turner wrote:
At least with light-guides (and perhaps PV cells on the surface
powering LEDs underground)


LEDs aren't particularly useful in this case. The reason why LEDs
use much less electricity than old fashioned light bulbs for the
same amount of light is that LEDs emit very little heat. So, the
inefficiency of less efficient lights is very efficient in this
case, they heat the greenhouse. LEDs probably are still the best
choice because you can choose your wave lengths more precicely and
because they last for such a long time, which is useful because an
artifically lighted greenhouse needs so much lights that changing
the light bulbs can be a waste of time. But there advantage is minimal.

Alain Fournier


I'm assuming it's better to manage heat and light as individually
controllable resources. Using incandescents combines the two even in
cases where you don't want or need both.

-michael turner

  #46  
Old July 22nd 10, 02:08 AM posted to sci.space.tech
Jonathan Thornburg [remove -animal to reply][_3_]
external usenet poster
 
Posts: 137
Default Technologies for Moon mission useable for missions further out

Alain Fournier wrote:
[[about MLI]]
Right, I wouldn't think that kind of insulation would be helpful
on Mars. On the Moon maybe because of longer nights and because
MLI is more efficient in vacuum than in the Martian atmosphere.


MLI doesn't work on or near the Martian surface -- the atmospheric
pressure is too high.

--
-- "Jonathan Thornburg [remove -animal to reply]"
Dept of Astronomy, Indiana University, Bloomington, Indiana, USA
"Washing one's hands of the conflict between the powerful and the
powerless means to side with the powerful, not to be neutral."
-- quote by Freire / poster by Oxfam

  #47  
Old January 26th 11, 02:12 PM posted to sci.space.tech
Alain Fournier[_2_]
external usenet poster
 
Posts: 373
Default Technologies for Moon mission useable for missions further out

greenaum wrote:
On Wed, 9 Jun 2010 20:35:21 EDT, Robert Heller
sprachen:


Air recycling: probably some sort of CO2 scrubber and/or some
sort of CO2 = C, O2 conversion: photosynthesis?
Water recycling: solar still?
Food: farming / gardening (Air/Water/Waste recycling on the side...).



It's worth pointing out that the only serious experiment into
biospheres, Biosphere 2 (you know, the giant airtight greenhouse they
built in the desert), failed horribly. Tho it did provide lots of
interesting information into why it failed. But their aim was to
support around 8 people in a closed system *on Earth*! And they didn't
manage that.

The site's still there, but before any sort of long-term colony
off-world, we need to revisit that project, and get it right first.
It's infinitely cheaper and safer to do it here before we start
sending colonists to the Moon.



Biosphere 2 was putting too much emphasis on being closed. You
don't want a martian habitat to be completely closed. You want
to bring in more stuff from time to time. There is nothing wrong
with pumping in some gas from outside and going to get the ores
you need. In fact you have to do that if you want to expand.
And if you are going to pump in some gas anyway, being completely
air-tight is not important. You want to lose as little air as
practical but don't go nuts about being air-tight.

I do agree that more experience in a somewhat closed system living
quarters would be nice, but you don't have to build such a big
thing as Biosphere 2 just to avoid all exchanges with the outside.
Exchanges with the outside aren't all that bad.


Alain Fournier

 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
NASA seeks ideas for mission, capailities and technologies Jacques van Oene News 0 November 11th 04 04:59 PM
multiple launch moon mission vs. Single Launch moon missions Fred K. Policy 2 March 20th 04 03:29 PM
New moon and mars missions... Robert Kent Space Shuttle 6 January 18th 04 09:06 PM
All Moon Missions Were Unmanned OM History 5 August 12th 03 09:07 PM
All Moon Missions Were Unmanned Bill Sheppard Misc 1 July 23rd 03 04:51 PM


All times are GMT +1. The time now is 10:20 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 SpaceBanter.com.
The comments are property of their posters.