QUESTION = Mars' atmosphere is 95% carbon dioxide. Could we plant trees to help convert it to oxygen and try to make it a habitable planet? GENERATION = Trees convert CO2 into O2. That's why you see trees in parks. Trees convert CO2 into O2. If you could convert it back into CO2, it would be easy enough to do. Plants don't convert CO2, but they do convert water, and they do that by using sunlight. If you could convert that back into CO2, you could convert it back into water. That's how the sun works. We can't convert that back into CO2, but we can convert it back into water. The problem is that the process isn't 100% efficient. The trees convert the CO2 into O2, and the water evaporates. The trees don't convert the O2 back into CO2, so the net result is that the trees are holding a lot of CO2. This means that the air around the trees is very acidic. This is bad for the trees, because they need to grow to get enough oxygen to make O2. We could make a tree that uses CO2 as a source of energy. It's called a "tree battery" and it's possible to do this. RETRIEVAL #0 = Mars habitat---a basis for bioengineering Mars into a more habitable place. As the bacteria reproduces the dead ones would create an organic layer in the regolith potentially paving the way for more advanced life. A study published in 2016 showed that cryptoendolithic fungi survived for 18 months in simulated Mars conditions. On Earth, plants that utilize the C4 photosynthesis reaction account for 3% of flowering plant species but 23% of carbon that is fixed, and includes species popular for human consumption including corn (aka maize) and sugar cane; certain types of plants may be more productive at producing food for a given amount of light. Plants noted for colonizing the barren landscape in the aftermath of the Mt Saint Helen's eruption included Asteraceae and Epilobium, and especially Lupinus lepidus for its (symbiotic) ability to fix its own nitrogen. (see also , Rhizobia, Nitrogen fixation) Section::::In-site resources. In situ resource utilization involves using materials encountered on Mars to produce materials needed. One idea for supporting a Mars habitat is to extract subterranean water, which with sufficient power could then be split into hydrogen and oxygen, with the intention of mixing the oxygen with nitrogen and argon for breathable air. The hydrogen can be combined with carbon dioxide to make plastics or methane for rocket fuel. Iron has also been suggested as a building material for 3 RETRIEVAL #1 = Atmosphere of Mars---the Martian atmosphere to make rocket fuel for the return mission. Mission studies that propose using the atmosphere in this way include the Mars Direct proposal of Robert Zubrin and the NASA Design reference mission study. Two major chemical pathways for use of the carbon dioxide are the Sabatier reaction, converting atmospheric carbon dioxide along with additional hydrogen (H), to produce methane (CH) and oxygen (O), and electrolysis, using a zirconia solid oxide electrolyte to split the carbon dioxide into oxygen (O) and carbon monoxide (CO). Section::::See also. BULLET::::- Climate of Mars BULLET::::- In situ resource utilization BULLET::::- Life on Mars BULLET::::- Mars MetNet – proposed surface observation network BULLET::::- Mars regional atmospheric modeling system BULLET::::- MAVEN orbiter BULLET::::- Seasonal flows on warm Martian slopes BULLET::::- Terraforming of Mars Section::::External links. BULLET::::- https://mars.nasa.gov Website for NASA Mars Exploration Program BULLET::::- http://www.msss.com/msss_images/ Summary of weekly weather on Mars prepared by Malin Space Science RETRIEVAL #2 = Space farming---a 2006 study suggests maintaining elevated CO concentrations can mitigate the effects of hypobaric conditions as low as 10 kPa to achieve normal plant growth. Martian soil contains a majority of the minerals needed for plant growth except for reactive nitrogen, which is a product of mineralization of organic matter. Since there is a lack of organic matter on the surface of mars, there is a lack of this component. Reactive nitrogen is a required constituent of soil used for plant growth, and it is possible that nitrogen fixing species, such as bacteria, could aide in the lack of reactive nitrogen series. However, a 2014 study suggested that plants were able to germinate and survive a period of 50 days on a Martian and lunar soil by using simulant soils. This being said, only one of their four experimented species did well enough to achieve full flower formation and more work would need to be done to achieve complete growth. Section::::Experiments. BULLET::::- The "GreenHab" at the Mars Desert Research Station in Utah contains a greenhouse which is designed to emulate some of the challenges resulting from farming on Mars. BULLET::::- The Lada experiment and the European Modular Cultivation System on the International Space Station is used to grow small amounts of fresh food. BULLET::::- In 2013, NASA funded research to develop a 3D food RETRIEVAL #3 = Carbon dioxide removal---few engineering proposals have been made for removing from the atmosphere, but work in this area is still in its infancy. Among the main technologies proposed, three of them stand out: causticization with alkali and alkali-earth hydroxides, carbonation, and organic−inorganic hybrid sorbents consisting of amines supported in porous adsorbents. A 2016 article reviews the research in these various areas. One proposed method is by so-called "artificial trees". This concept, proposed by climate scientist Wallace S. Broecker and science writer Robert Kunzig, imagines huge numbers of artificial trees around the world to remove ambient CO. The technology is now being pioneered by Klaus Lackner, the director of the Center for Negative Carbon Emissions (CNCE) and a professor in School of Sustainable Engineering and the Built Environment at Arizona State University, whose artificial tree technology can suck up to 1,000 times more CO from the air than real trees can at a rate of about one ton of carbon per day if the artificial tree is approximately the size of an actual tree. The CO would be captured in a filter and then removed from the filter and stored. The chemistry used is a variant of that described below, as it is based on sodium hydroxide. However, in a more recent design proposed by Klaus Lackner, the process can be carried out at only 40 RETRIEVAL #4 = Terraforming of Mars---would be necessary to cultivate such life inside a closed system. This would decrease the albedo of the closed system (assuming the growth had a lower albedo than the Martian soil), but would not affect the albedo of the planet as a whole. On April 26, 2012, scientists reported that lichen survived and showed remarkable results on the adaptation capacity of photosynthetic activity within the simulation time of 34 days under Martian conditions in the Mars Simulation Laboratory (MSL) maintained by the German Aerospace Center (DLR). One final issue with albedo reduction is the common Martian dust storms. These cover the entire planet for weeks, and not only increase the albedo, but block sunlight from reaching the surface. This has been observed to cause a surface temperature drop which the planet takes months to recover from. Once the dust settles it then covers whatever it lands on, effectively erasing the albedo reduction material from the view of the Sun. Section::::Proposed methods and strategies.:Funded research: ecopoiesis. Since 2014, the NASA Institute for Advanced Concepts (NIAC) program and Techshot Inc are working together to develop sealed biodomes that would employ colonies of oxygen-producing cyanobacteria and algae for the production of molecular oxygen (O) on Martian soil. But first they need to test if it works on a small scale RETRIEVAL #5 = Terraforming of Mars---the Chief Scientist at Techshot, a company located in Greenville, Indiana. They intend to send small canisters of extremophile photosynthetic algae and cyanobacteria aboard a future rover mission. The rover would cork-screw the canisters into selected sites likely to experience transients of liquid water, drawing some Martian soil and then release oxygen-producing microorganisms to grow within the sealed soil. The hardware would use Martian subsurface ice as its phase changes into liquid water. The system would then look for oxygen given off as metabolic byproduct and report results to a Mars-orbiting relay satellite. If this experiment works on Mars, they will propose to build several large and sealed structures called biodomes, to produce and harvest oxygen for a future human mission to Mars life support systems. Being able to create oxygen there would provide considerable cost-savings to NASA and allow for longer human visits to Mars than would be possible if astronauts have to transport their own heavy oxygen tanks. This biological process, called "ecopoiesis", would be isolated, in contained areas, and is not meant as a type of global planetary engineering for terraforming of Mars's atmosphere, but NASA states that "This will be the first major leap from laboratory studies into the implementation of experimental (as opposed to analytical) planetary "in situ" research of greatest interest to RETRIEVAL #6 = Reforestation---kind of tree to produce more forest cover would absorb more carbon dioxide from the atmosphere. On the other hand, a genetically modified tree specimen might grow much faster than any other regular tree. Some of these trees are already being developed in the lumber and biofuel industries. These fast-growing trees would not only be planted for those industries but they can also be planted to help absorb carbon dioxide faster than slow-growing trees. Extensive forest resources placed anywhere in the world will not always have the same impact. For example, large reforestation programs in boreal or subarctic regions have a limited impact on climate mitigation. This is because it substitutes a bright snow-dominated region that reflects the sunlight with dark forest canopies. On the other hand, a positive example would be reforestation projects in tropical regions, which would lead to a positive biophysical change such as the formation of clouds. These clouds would then reflect the sunlight, creating a positive impact on climate mitigation. There is an advantage to planting trees in tropical climates with wet seasons. In such a setting, trees have a quicker growth rate because they can grow year-round. Trees in tropical climates have, on average, larger, brighter, and more abundant leaves than non-tropical climates. A study of the girth of 70,000 trees across Africa has shown that tropical forests are soaking up more carbon dioxide