Astrobotany

Last updated

A zucchini being grown on the International Space Station Space zucchini.jpg
A zucchini being grown on the International Space Station

Astrobotany is an applied sub-discipline of botany that is the study of plants in space environments. It is a branch of astrobiology and botany.

Contents

Astrobotany concerns both the study of extraterrestrial vegetation discovery, as well as research into the growth of terrestrial vegetation in outer space by humans. [1]

It has been a subject of study that plants may be grown in outer space typically in a weightless but pressurized controlled environment in specific space gardens. [2] In the context of human spaceflight, they can be consumed as food and/or provide a refreshing atmosphere. [3] Plants can metabolize carbon dioxide in the air to produce valuable oxygen, and can help control cabin humidity. [4] Growing plants in space may provide a psychological benefit to human spaceflight crews. [4]

The first challenge in growing plants in space is how to get plants to grow without gravity. [5] This runs into difficulties regarding the effects of gravity on root development, providing appropriate types of lighting, and other challenges. In particular, the nutrient supply to root as well as the nutrient biogeochemical cycles, and the microbiological interactions in soil-based substrates are particularly complex, but have been shown to make possible space farming in hypo- and micro-gravity. [6] [7]

NASA plans to grow plants in space to help feed astronauts, and to provide psychological benefits for long-term space flight. [8]

Extraterrestrial vegetation

Astrobotany has been the investigation of the idea that alien plant life may exist on other planets. Here an artist has envisioned alien plants on shores of an exomoon exosea. Exoplanet Surface Water Life Exomoon.png
Astrobotany has been the investigation of the idea that alien plant life may exist on other planets. Here an artist has envisioned alien plants on shores of an exomoon exosea.

Vegetation red edge

The vegetation red edge (VRE) is a biosignature of near-infrared wavelengths that is observable through telescopic observation of Earth, and has increased in strength as evolution has made vegetative life more complex. [10] On Earth, this phenomenon has been detected through analysis of planetshine on the Moon, which can show a reflection spectrum that spikes at 700 nm. [10] In an article published in Nature in 1990, Sagan et al. described Galileo's detection of infrared light radiating from Earth as evidence of "widespread biological activity" [11] on earth, with evidence of photosynthesis a particularly strong factor.

The increase-in-strength of Earth's VRE biosignature has been assessed through modelling of early Earth radiation. [10] Mosses and ferns, which were dominant on Earth in the Ordovician and Carboniferous periods, produce weaker detectable infrared radiation spikes at 700 nm than modern Earth vegetation. [10] Astrobotanists focused on extraterrestrial vegetation have thus theorized that by using these same models, it could be possible to measure whether exoplanets in their respective Goldilocks zones currently hold vegetation, and by comparing VRE biosignatures to modelled historic Earth radiation, estimate the complexity of this vegetation. [12]

There are a number of obstacles to the detection of exoplanetary VREs:

Vegetation searches

Dubbed ‘the creator of astrobotany’, [1] Gavriil Adrianovich Tikhov coined the term in 1945 to describe the emerging field surrounding the search for extraterrestrial vegetation. Owing to storms on Mars that cause surface darkening visible from Earth, Tikhov's contemporaries often believed in the existence of Martian vegetation comparable to Earth's seasonal vegetation color changes. [14] [1] Building off of conclusions reached through examining earthshine on the Moon in 1914, in 1918 and 1921 Tikhov discovered through using telescopic color filters that chlorophylls were undetectable on the Martian surface, leading him to hypothesize that the character of Martian vegetation was likely to be blue hued, composed mostly of mosses and lichens. [1] Tikhov's research into astrobotany would later develop into research into growing plants in space, or demonstrating the possibility of plants to grow in extraterrestrial conditions (especially comparing the climate of Mars and Siberia), but he was the first known astronomer to use color to attempt to measure the level of vegetation on an extraterrestrial satellite. [1]

After Galileo's 1990 fly-by demonstrating the VRE effect on Earth, astrobotanical interest in extraterrestrial vegetation has mainly focused on examining the feasibility of VRE detection, [10] [13] [15] [16] and a number of projects have been proposed:

The James Webb Space Telescope has been searching the TRAPPIST-1 exoplanet system since 2021 for signs of extraterrestrial vegetation through capturing atmospheric data, including a VRE biosignature, that is made visible when TRAPPIST-1's exoplanets pass across the face of the star. NASA have judged three of TRAPPIST-1's rocky exoplanets (1e, 1f, and 1g) as within the habitable zone for liquid water (and other biological matter, such as vegetation). [16] [21]

Character of extraterrestrial vegetation

Accurate description of extraterrestrial vegetation character is highly speculative, but follows "solid physics and atmospheric chemistry" principles, according to Professor John Albert Raven from the University of Dundee. [17]

One factor determining the character of extraterrestrial vegetation is the star at the centre of the system. The Sun is a G-type main-sequence star, which provides the conditions for chlorophyll photosynthesis, and radiation levels that govern atmospheric conditions such as wind, affecting evolutionary development. TRAPPIST-1 is an ultra-cool red dwarf star, providing almost half the energy as the Sun, leading to astrobotanical speculation that vegetation in the TRAPPIST-1 exoplanet system could be much darker, even black to human eyes. [14]

F-type main-sequence stars, on the other hand, such as sigma Boötis, have been speculated to encourage the growth of either yellow-tinted, [17] or blue-tinted [14] [22] extraterrestrial vegetation within its exoplanet system, in order to reflect back the high levels of blue photons emitted by stars of its type.

Growing plants in space

The study of plant response in space environments is another subject of astrobotany research. In space, plants encounter unique environmental stressors not found on Earth including microgravity, ionizing radiation, and oxidative stress. [23] Experiments have shown that these stressors cause genetic alterations in plant metabolism pathways. Changes in genetic expression have shown that plants respond on a molecular level to a space environment. [24] Astrobotanical research has been applied to the challenges of creating life support systems both in space and on other planets, primarily Mars.

History

Russian scientist Konstantin Tsiolkovsky was one of the first people to discuss using photosynthetic life as a resource in space agricultural systems. Speculation about plant cultivation in space has been around since the early 20th century. [25] The term astrobotany was first used in 1945 by Soviet astronomer and astrobiology pioneer Gavriil Adrianovich Tikhov. [1] Tikhov is considered to be the father of astrobotany. Research in the field has been conducted both with growing Earth plants in space environments and searching for botanical life on other planets.

Seeds

The first organisms in space were "specially developed strains of seeds" launched to 134 km (83 mi) on 9 July 1946 on a U.S. launched V-2 rocket. These samples were not recovered. The first seeds launched into space and successfully recovered were maize seeds launched on 30 July 1946, which were soon followed by rye and cotton. These early suborbital biological experiments were handled by Harvard University and the Naval Research Laboratory and were concerned with radiation exposure on living tissue. [26] In 1971, 500 tree seeds (Loblolly pine, Sycamore, Sweetgum, Redwood, and Douglas fir) were flown around the Moon on Apollo 14. These Moon trees were planted and grown with controls back on Earth where no changes were detected.

Plants

The arugula-like lettuce Mizuna growing for Veg-03 ISS-53 Mizuna being cultivated inside the Veggie facility.jpg
The arugula-like lettuce Mizuna growing for Veg-03

In 1982, the crew of the Soviet Salyut 7 space station conducted an experiment, prepared by Lithuanian scientists (Alfonsas Merkys and others), and grew some Arabidopsis using Fiton-3 experimental micro-greenhouse apparatus, thus becoming the first plants to flower and produce seeds in space. [27] [28] A Skylab experiment studied the effects of gravity and light on rice plants. [29] [30] The SVET-2 Space Greenhouse successfully achieved seed to seed plant growth in 1997 aboard space station Mir . [4] Bion 5 carried Daucus carota and Bion 7 carried maize (aka corn).

Plant research continued on the International Space Station. Biomass Production System was used on the ISS Expedition 4. The Vegetable Production System (Veggie) system was later used aboard ISS. [31] Plants tested in Veggie before going into space included lettuce, Swiss chard, radishes, Chinese cabbage and peas. [32] Red Romaine lettuce was grown in space on Expedition 40 which were harvested when mature, frozen and tested back on Earth. Expedition 44 members became the first American astronauts to eat plants grown in space on 10 August 2015, when their crop of Red Romaine was harvested. [33] Since 2003 Russian cosmonauts have been eating half of their crop while the other half goes towards further research. [34] In 2012, a sunflower bloomed aboard the ISS under the care of NASA astronaut Donald Pettit. [35] In January 2016, US astronauts announced that a zinnia had blossomed aboard the ISS. [36]

in 2018 the Veggie-3 experiment was tested with plant pillows and root mats. [37] One of the goals is to grow food for crew consumption. [38] Crops tested at this time include cabbage, lettuce, and mizuna. [39]

Known terrestrial plants grown in space

'Outredgeous' red lettuce cultivar grown aboard the International Space Station. ISS-39 Steve Swanson with Veggie in the Columbus module.jpg
'Outredgeous' red lettuce cultivar grown aboard the International Space Station.

Plants that have been grown in space include:

Some plants, like tobacco and morning glory, have not been directly grown in space but have been subjected to space environments and then germinated and grown on Earth. [50]

Plants for life support in space

Lettuce being grown and harvested in the International Space Station before being frozen and returned to Earth. Growing Plants and Vegetables in a Space Garden.jpg
Lettuce being grown and harvested in the International Space Station before being frozen and returned to Earth.

Algae was the first candidate for human-plant life support systems. Initial research in the 1950s and 1960s used Chlorella, Anacystis, Synechocystis, Scenedesmus, Synechococcus, and Spirulina species to study how photosynthetic organisms could be used for O2 and CO2 cycling in closed systems. [51] Later research through Russia's BIOS program and the US's CELSS program investigated the use of higher plants to fulfill the roles of atmospheric regulators, waste recyclers, and food for sustained missions. The crops most commonly studied include starch crops such as wheat, potato, and rice; protein-rich crops such as soy, peanut, and common bean; and a host of other nutrition-enhancing crops like lettuce, strawberry, and kale. [52] Tests for optimal growth conditions in closed systems have required research both into environmental parameters necessary for particular crops (such as differing light periods for short-day versus long-day crops) and cultivars that are a best-fit for life support system growth.

Tests of human-plant life support systems in space are relatively few compared to similar testing performed on Earth and micro-gravity testing on plant growth in space. The first life support systems testing performed in space included gas exchange experiments with wheat, potato, and giant duckweed (Spyrodela polyrhiza). Smaller scale projects, sometimes referred to as "salad machines", have been used to provide fresh produce to astronauts as a dietary supplement. [51] Future studies have been planned to investigate the effects of keeping plants on the mental well-being of humans in confined environments. [53]

More recent research has been focused on extrapolating these life support systems to other planets, primarily Martian bases. Interlocking closed systems called "modular biospheres" have been prototyped to support four- to five-person crews on the Martian surface. [54] These encampments are designed as inflatable greenhouses and bases. [55] They are anticipated to use Martian soils for growth substrate and wastewater treatment, and crop cultivars developed specifically for extraplanetary life. [56] There has also been discussion of using the Martian moon Phobos as a resources base, potentially mining frozen water and carbon dioxide from the surface and eventually using hollowed craters for autonomous growth chambers that can be harvested during mining missions. [55]

Plant research

The study of plant research has yielded information useful to other areas of botany and horticulture. Extensive research into hydroponics systems was fielded successfully by NASA in both the CELSS and ALS programs, as well as the effects of increased photoperiod and light intensity for various crop species. [51] Research also led to optimization of yields beyond what had been previously achieved by indoor cropping systems. Intensive studying of gas exchange and plant volatile concentrations in closed systems led to increased understanding of plant response to extreme levels of gases such as carbon dioxide and ethylene. Usage of LEDs in closed life support systems research also prompted the increased use of LEDs in indoor growing operations. [57]

Experiments

Illustration of plants growing in a hypothetical Mars base. Mars Food Production - Bisected.jpg
Illustration of plants growing in a hypothetical Mars base.

Some experiments to do with plants include:

Results of experiments

A young sunflower plant aboard the ISS ISS-38 Young sunflower plant.jpg
A young sunflower plant aboard the ISS

Several experiments have been focused on how plant growth and distribution compares in micro-gravity, space conditions versus Earth conditions. This enables scientists to explore whether certain plant growth patterns are innate or environmentally driven. For instance, Allan H. Brown tested seedling movements aboard the Space Shuttle Columbia in 1983. Sunflower seedling movements were recorded while in orbit. They observed that the seedlings still experienced rotational growth and circumnation despite lack of gravity, showing these behaviors are built-in. [66]

Other experiments have found that plants have the ability to exhibit gravitropism, even in low-gravity conditions. For instance, the ESA's European Modular Cultivation System [67] enables experimentation with plant growth; acting as a miniature greenhouse, scientists aboard the International Space Station can investigate how plants react in variable-gravity conditions. The Gravi-1 experiment (2008) utilized the EMCS to study lentil seedling growth and amyloplast movement on the calcium-dependent pathways. [68] The results of this experiment found that the plants were able to sense the direction of gravity even at very low levels. [69] A later experiment with the EMCS placed 768 lentil seedlings in a centrifuge to stimulate various gravitational changes; this experiment, Gravi-2 (2014), displayed that plants change calcium signalling towards root growth while being grown in several gravity levels. [70]

Many experiments have a more generalized approach in observing overall plant growth patterns as opposed to one specific growth behavior. One such experiment from the Canadian Space Agency, for example, found that white spruce seedlings grew differently in the anti-gravity space environment compared with Earth-bound seedlings; [71] the space seedlings exhibited enhanced growth from the shoots and needles, and also had randomized amyloplast distribution compared with the Earth-bound control group. [72]

Astrobotany has had several acknowledgements in science fiction literature and film.

See also

Interior view the hypothetical O'Neill cylinder space habitat, showing alternating land and window stripes. Spacecolony3edit.jpeg
Interior view the hypothetical O'Neill cylinder space habitat, showing alternating land and window stripes.

Related Research Articles

<span class="mw-page-title-main">Astrobiology</span> Science concerned with life in the universe

Astrobiology is a scientific field within the life and environmental sciences that studies the origins, early evolution, distribution, and future of life in the universe by investigating its deterministic conditions and contingent events. As a discipline, astrobiology is founded on the premise that life may exist beyond Earth.

<span class="mw-page-title-main">Extraterrestrial life</span> Life that did not originate on Earth

Extraterrestrial life or alien life is life which does not originate from Earth. No extraterrestrial life has yet been conclusively detected. Such life might range from simple forms such as prokaryotes to intelligent beings, possibly bringing forth civilizations that might be far more advanced than humanity. The Drake equation speculates about the existence of sapient life elsewhere in the universe. The science of extraterrestrial life is known as astrobiology.

<span class="mw-page-title-main">Life on Mars</span> Scientific assessments on the microbial habitability of Mars

The possibility of life on Mars is a subject of interest in astrobiology due to the planet's proximity and similarities to Earth. To date, no proof of past or present life has been found on Mars. Cumulative evidence suggests that during the ancient Noachian time period, the surface environment of Mars had liquid water and may have been habitable for microorganisms, but habitable conditions do not necessarily indicate life.

<i>Destiny</i> (ISS module) Primary US ISS module

The Destiny module, also known as the U.S. Lab, is the primary operating facility for U.S. research payloads aboard the International Space Station (ISS). It was berthed to the Unity module and activated over a period of five days in February, 2001. Destiny is NASA's first permanent operating orbital research station since Skylab was vacated in February 1974.

A biosignature is any substance – such as an element, isotope, molecule, or phenomenon that provides scientific evidence of past or present life. Measurable attributes of life include its complex physical or chemical structures and its use of free energy and the production of biomass and wastes. A biosignature can provide evidence for living organisms outside the Earth and can be directly or indirectly detected by searching for their unique byproducts.

<span class="mw-page-title-main">Planetary habitability</span> Known extent to which a planet is suitable for life

Planetary habitability is the measure of a planet's or a natural satellite's potential to develop and maintain environments hospitable to life. Life may be generated directly on a planet or satellite endogenously or be transferred to it from another body, through a hypothetical process known as panspermia. Environments do not need to contain life to be considered habitable nor are accepted habitable zones (HZ) the only areas in which life might arise.

<span class="mw-page-title-main">Extraterrestrial materials</span> Natural objects that originated in outer space

Extraterrestrial material refers to natural objects now on Earth that originated in outer space. Such materials include cosmic dust and meteorites, as well as samples brought to Earth by sample return missions from the Moon, asteroids and comets, as well as solar wind particles.

<span class="mw-page-title-main">EXPOSE</span> External facility on the ISS dedicated to astrobiology experiments

EXPOSE is a multi-user facility mounted outside the International Space Station (ISS) dedicated to astrobiology. EXPOSE was developed by the European Space Agency (ESA) for long-term spaceflights and was designed to allow exposure of chemical and biological samples to outer space while recording data during exposure.

<span class="mw-page-title-main">TROPI</span> Scientific Experiment on the International Space Station

TROPI, or "Analysis of a Novel Sensory Mechanism in Root Phototropism", is an experiment on the International Space Station (ISS) to investigate the growth and development of plant seedlings under various gravity and lighting combinations. It was launched on Space Shuttle Endeavour during the STS-130 mission and was performed on the ISS during Expedition 22. Frozen plant samples from the TROPI experiment were returned on the landing of the STS-131 mission on Space Shuttle Discovery.

Interplanetary contamination refers to biological contamination of a planetary body by a space probe or spacecraft, either deliberate or unintentional.

<span class="mw-page-title-main">Space farming</span> Cultivation of crops in space

Space farming refers to the cultivation of crops for food and other materials in space or on off-Earth celestial objects – equivalent to agriculture on Moon.

<span class="mw-page-title-main">Plants in space</span> Growth of plants in outer space

The growth of plants in outer space has elicited much scientific interest. In the late 20th and early 21st century, plants were often taken into space in low Earth orbit to be grown in a weightless but pressurized controlled environment, sometimes called space gardens. In the context of human spaceflight, they can be consumed as food and/or provide a refreshing atmosphere. Plants can metabolize carbon dioxide in the air to produce valuable oxygen, and can help control cabin humidity. Growing plants in space may provide a psychological benefit to human spaceflight crews. Usually the plants were part of studies or technical development to further develop space gardens or conduct science experiments. To date plants taken into space have had mostly scientific interest, with only limited contributions to the functionality of the spacecraft, however the Apollo Moon tree project was more or less forestry inspired mission and the trees are part of a country's bicentennial celebration.

<span class="mw-page-title-main">Mars habitat</span> Facility where humans could live on Mars

A Mars habitat is a hypothetical place where humans could live on Mars. Mars habitats would have to contend with surface conditions that include almost no oxygen in the air, extreme cold, low pressure, and high radiation. Alternatively, the habitat might be placed underground, which helps solve some problems but creates new difficulties.

<span class="mw-page-title-main">Tanpopo mission</span> 2015–18 ISS astrobiology experiment

The Tanpopo mission is an orbital astrobiology experiment investigating the potential interplanetary transfer of life, organic compounds, and possible terrestrial particles in the low Earth orbit. The purpose is to assess the panspermia hypothesis and the possibility of natural interplanetary transport of microbial life as well as prebiotic organic compounds.

The Carl Sagan Institute: Pale Blue Dot and Beyond was founded in 2014 at Cornell University in Ithaca, New York to further the search for habitable planets and moons in and outside the Solar System. It is focused on the characterization of exoplanets and the instruments to search for signs of life in the universe. The founder and current director of the institute is astronomer Lisa Kaltenegger.

<span class="mw-page-title-main">Vegetable Production System</span>

The Vegetable Production System (Veggie) is a plant growth system developed and used by NASA in outer space environments. The purpose of Veggie is to provide a self-sufficient and sustainable food source for astronauts as well as a means of recreation and relaxation through therapeutic gardening. Veggie was designed in conjunction with ORBITEC and is currently being used aboard the International Space Station, with another Veggie module planned to be delivered to the ISS in 2017.

<span class="mw-page-title-main">Kennda Lynch</span> Astrobiologist and engineer for NASA programs

Kennda Lian Lynch is an American astrobiologist and geomicrobiologist who studies polyextremophiles. She has primarily been affiliated with NASA. She identifies environments on Earth with characteristics that may be similar to environments on other planets, and creates models that help identify characteristics that would indicate an environment might host life. Lynch also identifies what biosignatures might look like on other planets. Much of Lynch's research on analog environments has taken place in the Pilot Valley Basin in the Great Salt Desert of northwestern Utah, U.S. Her work in that paleolake basin informed the landing location of NASA's Perseverance Rover mission—at another paleolake basin called Jezero Crater. Jim Greene, Chief Scientist at NASA, called Lynch "a perfect expert to be involved in the Perseverance rover." Helping to select the proper landing site for NASA's first crewed mission to Mars in 2035 is another of Lynch's projects. Lynch has appeared in multiple television series, as well as The New York Times, Nature, Scientific American, and Popular Science. Cell Press designated Lynch one of the most inspiring Black scientists in the United States.

The UK Centre for Astrobiology was set up at the University of Edinburgh in 2011 by Charles Cockell. It was set up as a UK node, formally affiliated as an international partner with the NASA Astrobiology Institute (NAI) alongside other national nodes until the NAI's dissolution in 2019. It was established as a virtual centre to sit at the interdisciplinary boundary of planetary sciences/astronomy and biological/earth sciences investigating numerous aspects of life in the universe, specifically 'how habitable worlds form in the Universe and how life emerges, proliferates and leaves traces on these worlds' as well as engaging in work on the robotic and human exploration of space and in space ethics, philosophy and governance.

<span class="mw-page-title-main">MERMOZ</span> Way of remotely detecting living matter

MERMOZ is an astrobiology project designed to remotely detect biosignatures of life. Detection is based on molecular homochirality, a characteristic property of the biochemicals of life. The aim of the project is to remotely identify and characterize life on the planet Earth from space, and to extend this technology to other solar system bodies and exoplanets. The project began in 2018, and is a collaboration of the University of Bern, University of Leiden and Delft University of Technology.

References

  1. 1 2 3 4 5 6 Briot, Danielle (2013), Vakoch, Douglas A. (ed.), "The Creator of Astrobotany, Gavriil Adrianovich Tikhov", Astrobiology, History, and Society: Life Beyond Earth and the Impact of Discovery, Advances in Astrobiology and Biogeophysics, Berlin, Heidelberg: Springer, pp. 175–185, Bibcode:2013ahs..book..175B, doi:10.1007/978-3-642-35983-5_8, ISBN   978-3-642-35983-5 , retrieved 15 March 2023
  2. Guzman, Ana (7 April 2021). "Ways the International Space Station Helps Us Study Plant Growth in Space". NASA.
  3. "Plants in Space". NASA. 27 July 2016. Archived from the original on 19 July 2023.
  4. 1 2 3 4 5 T.Ivanova, et al. – First Successful Space Seed-to-Seed Plant Growth Experiment in the SVET-2 Space Greenhouse in 1997
  5. NASA – Getting to The Root of Plant Growth Aboard The Space Station
  6. Maggi, Federico; Pallud, Céline (November 2010). "Martian base agriculture: The effect of low gravity on water flow, nutrient cycles, and microbial biomass dynamics". Advances in Space Research . 46 (10): 1257–1265. Bibcode:2010AdSpR..46.1257M. doi:10.1016/J.ASR.2010.07.012. ISSN   0273-1177. Wikidata   Q55950873.
  7. Maggi, Federico; Pallud, Céline (2010). "Space agriculture in micro- and hypo-gravity: A comparative study of soil hydraulics and biogeochemistry in a cropping unit on Earth, Mars, the Moon and the space station". Planetary and Space Science. 58 (14–15): 1996–2007. Bibcode:2010P&SS...58.1996M. doi:10.1016/j.pss.2010.09.025.
  8. Rainey, Kristine (7 August 2015). "Crew Members Sample Leafy Greens Grown on Space Station". NASA. Retrieved 23 January 2016.
  9. F. J. Ballesteros; A. Fernandez-Soto; V. J. Martinez (2019). "Title: Diving into Exoplanets: Are Water Seas the Most Common?". Astrobiology . 19 (5): 642–654. doi:10.1089/ast.2017.1720. hdl: 10261/213115 . PMID   30789285. S2CID   73498809.
  10. 1 2 3 4 5 O'Malley-James, Jack T.; Kaltenegger, Lisa (1 September 2018). "The Vegetation Red Edge Biosignature Through Time on Earth and Exoplanets". Astrobiology. 18 (9): 1123–1136. arXiv: 1809.08832 . Bibcode:2018AsBio..18.1123O. doi:10.1089/ast.2017.1798. ISSN   1531-1074. PMID   30204495. S2CID   52189956.
  11. Sagan, Carl; Thompson, W. Reid; Carlson, Robert; Gurnett, Donald; Hord, Charles (October 1993). "A search for life on Earth from the Galileo spacecraft". Nature. 365 (6448): 715–721. Bibcode:1993Natur.365..715S. doi:10.1038/365715a0. ISSN   1476-4687. PMID   11536539. S2CID   4269717.
  12. 1 2 @NatGeoUK (27 September 2018). "How Earth's Vegetation Holds Clues to Alien Life on Other Planets". National Geographic. Retrieved 15 March 2023.
  13. 1 2 3 4 Seager, S.; Turner, E.l.; Schafer, J.; Ford, E.b. (1 June 2005). "Vegetation's Red Edge: A Possible Spectroscopic Biosignature of Extraterrestrial Plants". Astrobiology. 5 (3): 372–390. arXiv: astro-ph/0503302 . Bibcode:2005AsBio...5..372S. doi:10.1089/ast.2005.5.372. ISSN   1531-1074. PMID   15941381. S2CID   11589855.
  14. 1 2 3 4 Kiang, Nancy Y. (April 2008). "The Color of Plants on Other Worlds". Scientific American. 298 (4): 48–55. Bibcode:2008SciAm.298d..48K. doi:10.1038/scientificamerican0408-48. ISSN   0036-8733. PMID   18380141.
  15. Takizawa, Kenji; Minagawa, Jun; Tamura, Motohide; Kusakabe, Nobuhiko; Narita, Norio (8 August 2017). "Red-edge position of habitable exoplanets around M-dwarfs". Scientific Reports. 7 (1): 7561. arXiv: 1708.03773 . Bibcode:2017NatSR...7.7561T. doi:10.1038/s41598-017-07948-5. ISSN   2045-2322. PMC   5548919 . PMID   28790357.
  16. 1 2 Holt, Chris (22 April 2022). "How the James Webb Space Telescope will search for extraterrestrial l". Astronomy.com. Retrieved 15 March 2023.
  17. 1 2 3 Randerson, James; correspondent, Science (11 April 2007). "Alien 'plants' could be purple or yellow, say Nasa scientists". The Guardian. ISSN   0261-3077 . Retrieved 15 March 2023.
  18. "Timeline | ELT | ESO". elt.eso.org. Retrieved 15 March 2023.
  19. "How Extremely Large Telescopes will reveal exoplanets". cosmosmagazine.com. 23 October 2017. Retrieved 15 March 2023.
  20. Mennesson, Bertrand; Gaudi, Scott; Seager, Sara; Cahoy, Kerri; Domagal-Goldman, Shawn; Feinberg, Lee; Guyon, Olivier; Kasdin, Jeremy; Marois, Christian; Mawet, Dimitri; Tamura, Motohide; Mouillet, David; Prusti, Timo; Quirrenbach, Andreas; Robinson, Tyler (24 August 2016). MacEwen, Howard A.; Fazio, Giovanni G.; Lystrup, Makenzie; Batalha, Natalie; Siegler, Nicholas; Tong, Edward C. (eds.). "The Habitable Exoplanet (HabEx) Imaging Mission: preliminary science drivers and technical requirements". Proceedings, Space Telescopes and Instrumentation 2016: Optical, Infrared, and Millimeter Wave. Space Telescopes and Instrumentation 2016: Optical, Infrared, and Millimeter Wave. Edinburgh, United Kingdom. 9904: 99040L. Bibcode:2016SPIE.9904E..0LM. doi:10.1117/12.2240457. hdl: 1721.1/116467 . S2CID   1289944.
  21. "The TRAPPIST-1 Habitable Zone". HubbleSite.org. Retrieved 15 March 2023.
  22. "Life under alien skies". Physics World. 1 April 2012. Retrieved 15 March 2023.
  23. http://astrobotany.com/plants-and-spaceflight/ | Challenges of Growing Plants in Space
  24. Li, Huasheng; Lu, Jinying; Zhao, Hui; Sun, Qiao; Yu, Futong; Pan, Yi; Chen, Yu; Su, Liang; Liu, Min (2017). "The impact of space environment on gene expression in Arabidopsis thaliana seedlings". Science China Technological Sciences. 60 (6): 902–910. Bibcode:2017ScChE..60..902L. doi:10.1007/s11431-016-0232-7. S2CID   125206061.
  25. https://www.degruyter.com/downloadpdf/j/opag.2017.2.issue-1/opag-2017-0002/opag-2017-0002.pdf | Agriculture for Space: People and Places Paving the Way
  26. Beischer, DE; Fregly, AR (1 January 1962). Animals and man in space. A chronology and annotated bibliography through the year 1960 (Report). Vol. ONR TR ACR-64. US Naval School of Aviation Medicine. Retrieved 5 November 2022.
  27. "First species of plant to flower in space" . Retrieved 20 January 2016.
  28. "No NASA, These Are Not The First Plants To Flower in Space". 16 January 2016. Retrieved 20 January 2016.
  29. 1 2 "Plant Growth/Plant Phototropism – Skylab Student Experiment ED-61/62". Archived from the original on 4 August 2014. Retrieved 9 May 2018.
  30. NASA SP-401 – Chapter 5
  31. "NASA – VEGGIE". Archived from the original on 22 December 2018. Retrieved 9 May 2018.
  32. "NASA – Station Investigation to Test Fresh Food Experience".
  33. Kluger, Jeffrey (10 August 2015). "Why Salad in Space Matters". Time .
  34. Bauman, Joe (16 June 2003). "USU EXPERIMENT FEEDS ASTRONAUTS' MINDS, TASTE BUDS". Deseret News, Space Dynamics Laboratory. Archived from the original on 14 February 2019. Retrieved 9 May 2018.
  35. "June 17–26 – Diary of a Space Zucchini". 29 June 2012. Retrieved 20 January 2016.
  36. Kooser, Amanda (18 January 2016). "Behold the first flower to bloom in space, a cheerful zinnia". CNET .
  37. "NASA Space Station On-Orbit Status 6 February 2018 – Celebrating 10 Years of ESA's Columbus Module – SpaceRef". spaceref.com. Archived from the original on 1 October 2021. Retrieved 8 February 2018.
  38. "NASA Space Station On-Orbit Status 6 February 2018 – Celebrating 10 Years of ESA's Columbus Module – SpaceRef". spaceref.com. Archived from the original on 1 October 2021. Retrieved 8 February 2018.
  39. "NASA Space Station On-Orbit Status 6 February 2018 – Celebrating 10 Years of ESA's Columbus Module – SpaceRef". spaceref.com. Archived from the original on 1 October 2021. Retrieved 8 February 2018.
  40. Administrator, NASA (7 June 2013). "Getting to The Root of Plant Growth Aboard The Space Station". NASA. Retrieved 8 April 2018.
  41. 1 2 3 4 5 "Growing Pains". Air & Space Magazine. Retrieved 8 April 2018.
  42. Heiney, Anna (17 February 2017). "Cabbage Patch: Fifth Crop Harvested Aboard Space Station". NASA. Retrieved 8 April 2018.
  43. "NASA – A Plant Growth Chamber". www.nasa.gov. Retrieved 8 April 2018.
  44. "NASA Space Station On-Orbit Status 6 February 2018 – Celebrating 10 Years of ESA's Columbus Module – SpaceRef". spaceref.com. Archived from the original on 1 October 2021. Retrieved 8 April 2018.
  45. "ISS space flowers may need some help from 'Martian'". Florida Today. Retrieved 8 April 2018.
  46. "'Outredgeous' Red Romaine Lettuce, Grown Aboard The International Space Station, To Be Taste-Tested By Astronauts". Medical Daily. 10 August 2015. Retrieved 8 April 2018.
  47. "Photo-iss038e000734". spaceflight.nasa.gov. Archived from the original on 21 April 2014. Retrieved 8 April 2018.
  48. Salmi, Mari L.; Roux, Stanley J. (December 2008). "Gene expression changes induced by space flight in single-cells of the fern Ceratopteris richardii". Planta. 229 (1): 151–159. doi:10.1007/s00425-008-0817-y. ISSN   0032-0935. PMID   18807069. S2CID   30624362.
  49. "'NASA Science to Return to Earth aboard SpaceX Dragon Spacecraft". NASA. 1 May 2018. Retrieved 8 May 2018.
  50. Tepfer, David; Leach, Sydney (2017). "Survival and DNA Damage in Plant Seeds Exposed for 558 and 682 Days outside the International Space Station". Astrobiology. 17 (3): 205–215. Bibcode:2017AsBio..17..205T. doi:10.1089/ast.2015.1457. PMC   5369387 . PMID   28263676.
  51. 1 2 3 Wheeler, Ray (1 January 2011). "Plants for human life support in space: From Myers to Mars". Gravitational and Space Biology. 23.
  52. Wheeler, Ray; Sager, John (1 February 2003). "Crop Production for Advanced Life Support Systems - Observations From the Kennedy Space Center Breadboard Project". NASA Technical Reports.
  53. Lucie, Poulet; D., Massa, G.; R., Wheeler; T., Gill; R., Morrow; C., Steele; T., Swarmer; K., Binsted; J., Hunter (2014). "Demonstration test of electrical lighting systems for plant growth in HI-SEAS analog mars habitat". elib.dlr.de. Retrieved 8 April 2018.{{cite web}}: CS1 maint: multiple names: authors list (link)
  54. Silverstone, S; Nelson, M; Alling, A; Allen, J (1 January 2003). "Development and research program for a soil-based bioregenerative agriculture system to feed a four person crew at a Mars base". Advances in Space Research. 31 (1): 69–75. Bibcode:2003AdSpR..31...69S. doi:10.1016/S0273-1177(02)00661-0. ISSN   0273-1177. PMID   12577934.
  55. 1 2 Wheeler, R.M. (2000). Mars Greenhouses: Concepts and Challenges (PDF). NASA.
  56. Nelson, M; Alling, A; Dempster, W. F; Van Thillo, M; Allen, John (1 January 2003). "Advantages of using subsurface flow constructed wetlands for wastewater treatment in space applications: Ground-based mars base prototype". Advances in Space Research. 31 (7): 1799–1804. Bibcode:2003AdSpR..31.1799N. doi:10.1016/S0273-1177(03)00013-9. ISSN   0273-1177. PMID   14503520.
  57. Morrow, Robert C. (1 December 2008). "LED Lighting in Horticulture". HortScience. 43 (7): 1947–1950. doi: 10.21273/HORTSCI.43.7.1947 . ISSN   0018-5345.
  58. "NASA – Station Investigation to Test Fresh Food Experience". www.nasa.gov. Retrieved 23 January 2016.
  59. Glow-in-the-Dark Plants on the ISS
  60. Encyclopedia Astronautica Salyut 7
  61. Plant Signaling (STS-135) Archived 16 February 2013 at the Wayback Machine
  62. Shimazu T, Aizawa S (1999). "STS-95 Space Experiments (plants and cell biology)". Biol Sci Space. 13 (1): 25–32. doi: 10.2187/bss.13.25 . PMID   11542477.
  63. NASA's New Space 'Botanist' Arrives at Launch Site. NASA. 17 April 2018.
  64. ECOSTRESS – Home web site at NASA.
  65. SS038-E-000734 (13 November 2013)
  66. Chamovitz, Daniel (2012). What a plant knows : a field guide to the senses (1st ed.). New York: Scientific American/Farrar, Straus and Giroux. ISBN   978-0-374-28873-0.
  67. Jost, Ann-Iren Kittang; Hoson, Takayuki; Iversen, Tor-Henning (20 January 2015). "The Utilization of Plant Facilities on the International Space Station—The Composition, Growth, and Development of Plant Cell Walls under Microgravity Conditions". Plants. 4 (1): 44–62. doi: 10.3390/plants4010044 . ISSN   2223-7747. PMC   4844336 . PMID   27135317.
  68. Driss-Ecole, Dominique; Legué, Valérie; Carnero-Diaz, Eugénie; Perbal, Gérald (1 September 2008). "Gravisensitivity and automorphogenesis of lentil seedling roots grown on board the International Space Station". Physiologia Plantarum. 134 (1): 191–201. doi:10.1111/j.1399-3054.2008.01121.x. ISSN   1399-3054. PMID   18429941.
  69. "Scientific objectives". Plants in space: GRAVI-2 experiment. 28 March 2014.
  70. "A decade of plant biology in space". European Space Agency.
  71. "NASA – Advanced Plant Experiment – Canadian Space Agency 2". www.nasa.gov.
  72. Rioux, Danny; Lagacé, Marie; Cohen, Luchino Y.; Beaulieu, Jean (1 January 2015). "Variation in stem morphology and movement of amyloplasts in white spruce grown in the weightless environment of the International Space Station". Life Sciences in Space Research. 4: 67–78. Bibcode:2015LSSR....4...67R. doi:10.1016/j.lssr.2015.01.004. PMID   26177622.
  73. Sheffield, Charles (1989). Proteus Unbound . New York, NY: Random House Publishing Group. ISBN   9780345344342.
  74. Cameron, James, Director. Avatar. Produced by James Cameron and Jon Landau, 20th Century Fox, 2009. Accessed 18 March 2018.
  75. Weir, Andy (2014). The Martian . New York, NY: CrownPublishing. ISBN   978-0553418026.