File:Eden project.jpg

2010-04-21T15:39:23Z

204.43.192.70: /* Description */

:Image credit: [http://commons.wikimedia.org/wiki/User:J%C3%BCrgenMatern Jürgen Matern]
:Source: http://en.wikipedia.org/wiki/Image:Eden_Project_geodesic_domes_panorama.jpg

[[Media:=]]==Description===
Panoramic view of the geodesic dome structures of the Eden Project. The Eden Project is a large-scale environmental complex near St Austell, Cornwall, England, United Kingdom. The project was conceived by Tim Smit and has quickly become one of the most popular visitor attractions in the United Kingdom. The complex includes two giant, transparent domes made of ETFE cushions, each emulating a natural biome, that house plant species from around the world. The first emulates a tropical environment, the other a warm temperate, mediterranean environment. The project took 2½ years to construct and opened to the public in March 2001.

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[[category:images]] u suck

Greenhouse effect

2010-04-21T15:37:09Z

204.43.192.70: /* Artificial Greenhouse Effect */

==Definition==

Short-wave electromagnetic [[radiation]] from the [[Sun]] passes through the transparent atmosphere
unhindered (except for the effect that [[albedo]] has on the mean reflectivity of a planet). On heating the planet's surface, long-wave radiation (i.e. Infrared radiation) is emitted into the atmosphere. Long-wave radiation will not escape into space if the [[atmosphere]] is dense enough, and contains [[greenhouse gases]] (such as [[carbon dioxide]], [[water]] vapour, [[methane]] etc.) which reflect long-wave radiation back to the surface, heating the atmosphere further. This shortwave input, long-wave emission, long-wave reflection, atmospheric heating process is known as the '''Greenhouse Effect'''.

==[[Terraforming]] Mars==

The Greenhouse Effect is an essential process to heat a planet's atmosphere to habitable temperatures. To make life sustainable on the surface of Mars, the process of [[:category:Terraforming Mars|terraforming]] would require a thickening of the tenuous Martian atmosphere and injection of selected [[greenhouse gases]]. Decreasing the planet's [[albedo]] would also be beneficial.

Hopefully nobody will read this =D

==Examples of the Greenhouse Effect==

*[[Venus]] has a very dense atmosphere, causing a ''runaway'' greenhouse effect. Temperatures on Venus' surface are increased by 400 degrees by this extreme heating creating a surface temperature of over 700 Kelvin and surface pressure of 90 times that of the Earth's atmosphere (about 1350 pounds per square inch).
*[[earth|Earth's]] [[global warming]] is believed to be in direct correlation with carbon emissions from industrial burning of [[fossil fuels]] and other human activity. It is believed the planet will reach a "tipping point" where the heating cannot be sustained by the atmosphere causing a catastrophic collapse in [[weather systems]] and climate shift.

[[category:Terraforming Mars]]
[[category:Climate]]

Greenhouse

2010-04-21T15:36:16Z

204.43.192.70: /* Flora and fauna */

[[image:Eden_project.jpg|thumb|right|300px|[[The Eden Project]]] (near St Austell, Cornwall, UK) is a terrestrial example of the possible use of large ''biomes'' as greenhouses and life support for Mars colonies. ''Image credit: Jürgen Matern]]
Growing [[:category:plants|plants]] in a '''Greenhouse''' delivers [[oxygen]] and [[food]]. It can play an important part in human recreation ([[Mars Garden Wins Gold at London’s Chelsea Flower Show (MarsHome.org)|Mars Garden]]) and may be the place for [[funeral]]s. The [[sunlight]] is not bright enough on Mars to allow usual terrestrial plants to thrive, but it provides a valuable part of light energy for plants. Additional [[energy]] is necessary for lighting and heating.

The greenhouse will be constructed from transparent material, allowing maximum sunlight to pass, generating an artificial "[[greenhouse effect]]". The spectral properties of the material should be optimized to match the absorption characteristics of chlorophyll, maximizing the energy gain.

Plants need a mix of air pressure and temperature. The greenhouse must be strong enough to hold that air pressure, and it must be [[insulation|insulated]] to hold the temperature inside. Photosynthesis works only at fairly high temperatures.

==Side-lit Greenhouse Concept==

[[Image:Greenhouse_marsfoundation.jpg|thumb|left|300px|The [[Mars Foundation]] concept for a side-lit greenhouse.]]
The [[Mars Foundation]] concept for a greenhouse involves the maximum use of local materials to avoid waste, maximize energy input and optimize space. Spawned from the [[Hillside settlement]] design, the greenhouse would most likely be located inside/next to a hill side (possibly in the location of [[Candor Chasma]]). Therefore [[regolith]] or some other absorbant material could be suspended above the greenhouse to protect occupants and plants from [[solar radiation|harmful radiation]]. The source of light would therefore be directed from the side, via an array of adjustable mirrors. A system of vents and ducts would allow warm air to circulate, perhaps even used to heat the main habitat.

==Underground Greenhouse Concept==
[[Image:Underground Greenhouse.png|thumb|right|300px|Underground Greenhouse Concept]]

If geothermal energy is not available the heating will consume large amounts of electrical energy. In this case the sum of energy used for lighting and heating must be considered. An underground greenhouse is easier to insulate to hold warmth inside. On the other hand the effort of lighting is higher, since no direct sunlight is used. This concept has some additional advantages: It is [[meteorites|meteorite]]-safe and [[radiation]]-safe.

[[caves|Natural caves]] and [[artificial cave]]s can be utilized to build such an underground greenhouse, which requires a preparation with high effort in either case. The maintenance is quite cheep, for the ambient temperatures are steady and the radiation levels are low, so it is a good long term solution. A combination of greenhouse and living space for the settlers is suggested.

==Water-shield Greenhouse Concept==

[[Image:WaterShieldGreenhouse.png|thumb|right|300px|Water-shield Greenhouse Concept]]
[[Hydrogen]] does a good job absorbing [[cosmic radiation]]. [[Water]] contains highly concentrated hydrogen, and hence serves as a good radiation shield. On the other hand it is highly transparent for visible light and UV. The combination of both makes it an interesting material for greenhouse shielding.

Under a strong pressure resistent housing the water is placed in a thick layer. It absorbes the dangerous parts of cosmic radiation and [[sunlight]] and passes most of the spectral parts needed by [[human]]s and plants. Additionally, it helps to buffer daily temperature variations because of its high specific heat capacity.

The layering could be as follows: The outer layer is a construction of [[steel]] and [[glass]], providing enough strength for the difference in [[atmosphere|atmospheric pressure]]. It also serves as insulation for [[temperature]] differences. Additional sheets of glass or [[Synthetic materials|plastics]] improve the insulation effect. A [[self-healing puncture protection]] should be considered. The innermost layer is the water. It can be held by transparent canisters.

==Multiplying Sunlight==
[[Image:MultipleMirrorsForGreenhouse.png|thumb|left|300px|Multiple Mirrors for Greenhouse]]

A [[solar concentrator‎]] is a set of mirrors that can be used to bring more sunlight into the greenhouse than the base area of the greenhouse receives directly from the sun. Three times the amount of Martian sunlight should be enough to serve terrestrial plants. During good weather periods this allows growing vegetables without additional energy.

==Nutrition and Energy Calculations==
Based upon the figures in the [[food]] and [[sunlight]] articles the following calculations can be carried out for an artificially lit greenhouse:

The minimum size of cropland per person is about 365 m<sup>2</sup>. The needed light energy can be assumed with 1000 kWh per m<sup>2</sup> and year. The result is an annual amount of 365 MWh per person. In other words: An average illumination power of 41,67 kW per person is required.

The usage of fluorescent lamps with an efficiency factor of 30% results in a requirement of about 140 kW per person in electrical energy. The overall efficiency of food production with artificially lit greenhouses is less then 1 permille, or in other words, to produce food with a content of 1 kWh the amount of more than 1 MWh in electricity must be spent.

Parts of the required light can possibly be provided by direct or indirect sunlight. Heating the greenhouse will require additional energy.

==Open Issues==
*How long can plants survive without sunlight (e.g. during a dust storm)?
*How many persons are needed to work in the greenhouse to produce enough food for a hundred persons?
*How much energy is required for heating, especially during long lasting dust storms? This question can not be answered without an [[experimental setup#greenhouse heating|experimental setup]].
*What temperature and air pressure do plants need?
*What air pressure is needed for persons to work in the greenhouse?
*What transparent materials match the absorption characteristics of chlorophyll?
*Do plants need wind? How can it be provided?

==External links==
*[http://www.marshome.org/archives/2007/03/sidelit_greenho.php The Mars Foundation Side-lit Greenhouse design.]

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[[category:biospherics]]
[[category:greenhouse]]
[[category:agriculture]]

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File:Eden project.jpg

Greenhouse effect

Greenhouse