Creating the MoonÕs Atmosphere

(Maintaining an atmosphere suitable for plant growth within Lunar Habitats)

By Heidi Castellanos

Packer Engineering, Inc.

Summer Intern 2006

Supervised by Peter J. Schubert

I.          Plants

            A.        Plants that will withstand 14 days of darkness

                        1.         Low Light Plants

a.         Silver Evergreen, Silver King Evergreen, Chinese Evergreen, Cast-iron Plant, Variegated Cast-iron Plant, Parlor Palm, Golden Pothos, Marble Queen Pothos, Split-leaf Philodendron, Snake Plant, Goldband Sansevieria (1)

b.         light requirement is minimum 100 ft-c, 75 to 200 preferred for good growth (1)

                        2.         Medium Light Plants

a.         Silver Vase, Plume Asparagus, Sprengeri Asparagus, Fern Asparagus, Gold-dust Plant, Schefflera, Dwarf Schefflera, Fishtail Palm, Bamboo Plant, Spider Plant, Grape Ivy, Giant Dumbcane, Spotted Dumbcane, False Aralia, Striped Dracaena, Corn Plant, Gold-dust Dracaena, Red-margined Dracaena, Ribbon Plant, Japanese Fatsia, Weeping Fig, India Rubber Plant, Fiddle-leaf Fig, Indian Laurel, Velvet Plant, English Ivy, Kentia Palm, Red-veined Prayer Plant, Boston Fern, Emerald Ripple Peperomia, Oval-leaf Peperomia, Fiddle-leaf Philodendron, Heart-leaf Philodendron, Tree Philodendron, Aluminum Plant, Friendship Plant, Swedish Ivy, Variegated Balfour Aralia, African Violet, Cleveland Peace Lily, Mauna Loa Peace Lily, Trileaf Wonder Nephthytis, Inch Plant, Wandering Jew (1)

b.         light requirement is minimum 100 to 150 ft-c, 200 to 500 preferred (1)

            B.        Plants that will grow under artificial light

1.         Aloe Vera, JosephÕs Coat, Zebra Plant, Norfolk Island Pine, Ponytail Palm, Kangaroo Vine, Calamondin Orange, Coffee, Coleus, Ti Plant, Jade Plant, Botanical Wonder, Chinese Hibiscus, Wax Plant, Blood Leaf, Weeping Pododarpus, Ming Aralia, Moses-in-the-Cradle, Christmas Cactus, BurroÕs Tail (1)

2.         light requirement is minimum 150 to 1000 ft-c, 500 to 1000 preferred (1)

II.        Nitrogen Oxide Scrubber

            -- a gas scrubber that uses ammonia, or a catalyst and ammonia solution, to remove nitrogen oxide from a gas stream.

 

III.       Carbon Dioxide (Potassium hydroxide) Scrubber 

            A.        CO2 Poisoning -- It's the lack of O2 that normally accompanies high CO2 levels. Since ambient air carries 21% O2, any significant increase in CO2 results in a corresponding decrease in available O2. This is a much different mechanism than CO poisoning, which can occur at very low levels due to its highly efficient displacement of O2 in the blood. Unlike CO2, if you had CO levels high enough to significantly reduce ambient O2 levels, probably a single breath would kill you. hypoxia is the cause of death in either case, but death by CO poisoning wouldn't be called suffocation whereas death by (6)

B.        Apollo 13 technology (9)

C.        Plants

1.         Reasons for plants -- clean the air, humidify the air, invigorate energy (5)

                        2.         Hardy Plants Peace Lily, Dracaena ŌJanet CraigÕ, Chinese

                                    Evergreen, Polthos Ivy, Philodendron Selloum (5)

D.            Biosphere 2 technology (8)

 

IV.       Odor Filtering (closed environment)  

           

V.        Humidity Control

            A.        Humidity Control Chamber (7)

 

            B.        Environmental Chamber (7)

 

VI.       Mining Oxygen

A.        Mining oxygen from the lunar soil -- To separate ilmenite into its primary constituents, we add hydrogen and heat the mixture. This produces raw iron, rutile, and water. With just those water molecules, we can immediately recover 10.5% of the weight of the regolith as oxygen. To get pure titanium and more oxygen, we'll have to use a more complex process, perhaps using a chlorine or flourine reaction; but for the initial pilot plant we have an easier approach. Water is made of just hydrogen and oxygen, so we can use simple electrolysis to separate the two gasses. (4)



            B.        Diagram of lunar oxygen pilot plant (4)

 

 


VII.      EarthÕs Atmosphere vs. MoonÕs Atmosphere

            A.        EarthÕs Atmosphere

1.         Composition -- 78% nitrogen, 21% oxygen, 0.04% Carbon Dioxide, ~0.9% Argon (3)

                        2.         Problems        

a.         The Greenhouse Effect -- The greenhouse effect is a natural process which made life on Earth possible. Without naturally occurring greenhouse gases such as water vapour, carbon dioxide, methane and nitrous oxide, the Earth's surface temperature would be 33”C cooler, a chilly -18”C rather than the tolerable 15”C. (3)

b.         Damage to the Ozone Layer -- There is a layer of ozone high up in the atmosphere which shields the Earth from the sun's harmful UV rays, these rays can lead to an increase in skin cancer. The ozone is present in very small quantities but it is enough to absorb the UV rays preventing them reaching the surface. (3)

c,         Acid Rain -- Rain water is naturally acidic due to carbon dioxide which partially reacts with water to give carbonic acid (H2O + CO2   ->  H2CO3). Acid rain is the enhanced effect which is caused by other gases released when fossil fuels are burnt. (3)

            B.        MoonÕs Atmosphere

                        1.         Composition there is no atmosphere

                        2.         Problems

a.         Moon is too small to hold an atmosphere so near to the Sun Solar radiation acts to strip atmosphere away from any solar system body, so that an atmosphere is a tug-of-war between the planet/moon/asteroid/whatever, which uses gravity to hold on to gases, and the Sun, which is acting to drive the gases away. (2)

b.         The random motion due to thermal energy of the gases also acts to "evaporate" the atmosphere. This depends on temperature (more molecular agitation at higher temperatures), but at "room temperature" this would a significant factor in leaking the Moon's atmosphere from its gravitational grasp. (2)

c.         The moon looses gases -- A gas is a collection of particles bouncing around. The hotter the gas is, the faster the particles move. The lighter the gas particles are, the faster they move at a given temperature. On the earth, the gravity field is relatively high, and the range of surface temperatures isn't hot enough to cause the gas particles to reach escape velocity. So lightweight gasses stay in the atmosphere. On the moon, surface temperatures reach 200 degrees F, causing molecules of the lighter gasses hydrogen) to move faster to lunar escape velocity. So they escape into free space. (4)

 

http://hgic.clemson.edu/factsheets/HGIC1450.htm (1)

 

http://www.madsci.org/posts/archives/feb98/887133573.As.r.html (2)

 

http://www.moorlandschool.co.uk/earth/atmosphere.htm (3)

 

http://www.asi.org/adb/04/03/10/04/oxygen-extraction.html (4)

http://www.apartmenttherapy.com/ny/good-questions/good-questions-low-light-plants-002195 (5)

http://yarchive.net/med/co2_poisoning.html (6)

http://www.humiditycontrol.com/  (7)

http://en.wikipedia.org/wiki/Biosphere_2 (8)

http://www.ghg.net/woodfill/Apollo_13_CO2_filter.htm (9)