EXPOSE
[4] EXPOSE data support long-term in situ studies of microbes in artificial meteorites, as well as of microbial communities from special ecological niches.The chemical set of experiments is designed to reach a better understanding of the role of interstellar, cometary and planetary chemistry in the origin of life.[1] The biology experiments used the full extraterrestrial spectrum of solar UV radiation and suitable cut-off filters to study both, the role of the ozone layer in protecting our biosphere and the likelihood of resistant terrestrial microorganisms (extremophiles) to survive in outer space.The different experiments consisted in exposing solid molecules, gas mixtures or biological samples to the solar ultraviolet (UV) radiation, cosmic rays, vacuum and temperature fluctuations of outer space as the ISS repeatedly passed between areas of direct sunlight and the cold darkness of Earth's shadow.[3][7] At the end of the exposition period, EXPOSE-E was brought back to the ground in September 2009 as part of the Space Shuttle Discovery mission STS-128.The results also demonstrate the protective effect of meteorite powder, which reemphasizes the importance of exogenic contribution to the inventory of prebiotic organics on early Earth.[12] Bacterial endospores of the highly UV-resistant Bacillus subtilis strain MW01 were exposed to low Earth orbit and simulated Martian surface conditions for 559 days.Also, the first-generation cells and spores derived from space-exposed samples exhibited elevated ultraviolet-C resistance when compared with their ground control counterparts.[21] According to the researchers, the studies provide experimental information on the possibility of eukaryotic life transfer from one planet to another by means of rocks and of survival in Mars environment.[20] Cryptoendolithic microbial communities and epilithic lichens have been considered as appropriate candidates for the scenario of lithopanspermia, which proposes a natural interplanetary exchange of organisms by means of rocks that have been impact ejected from their planet of origin.Of the 2100 exposed wild-type Arabidopsis thaliana and Nicotiana tabacum (tobacco) seeds, 23% produced viable plants after being returned to Earth.Each tray was loaded with a variety of biological organisms including plant seeds and spores of bacteria, fungi and ferns that were exposed to the harsh space environment for about one and a half years.The ROSE (Response of Organisms to Space Environment) group of experiments are under the coordination of the German Aerospace Center (DLR) and has been composed of scientists from different European countries, from United States and from Japan.[1] In its 8 experiments of biological and chemical content, more than 1200 individual samples were exposed to solar ultraviolet (UV) radiations, vacuum, cosmic rays or extreme temperature variations.[30] As the brown film should have impacted the quantity and quality of solar light that reached the test samples, affecting the core of the scientific goals, an investigation was started to identify the properties and the root cause of the colour change.
International Space StationastrobiologyEuropean Space Agencylong-term spaceflightsouter spacephotobiological processesUV-B radiationmicrobesorganismsorganic moleculessolar lightorganic matterRosetta missionCassini–HuygensMars Science LaboratoryExoMarsorigin of lifeevolutionlife on Earth67P/Churyumov–GerasimenkoCuriosityozone layerbiosphereextremophileslithopanspermiaplanetary protectionMartian soilSpace Shuttle AtlantisColumbusEuropean Technology Exposure FacilityBaikonur CosmodromeKazakhstanProgress capsuleultravioletcosmic rayssunlightSpace Shuttle DiscoverySTS-128Soyuz spacecraftMoscowmicroorganismslichenssymbiotespanspermiaionizing radiationmolecular biologyglycineserinephthalic acidmellitic acidamino acidsdipeptidecosmic radiationaspartic acidaminobutyric acidalaninevalineaminoisobutyric acidendosporesBacillus subtilislow Earth orbitsolar irradiationHalococcus dombrowskiiphototrophicChroococcidiopsisChlorellaGloeocapsathyminethymine dimerBacillus pumilusmutagenicproteomicssuperoxide dismutaseforward contaminationAcarosporaSuprasilStichococcusgreen algaeCryomyces antarcticusCryomyces minteriNicotiana tabacumArabidopsis thalianaionizingnon-ionizing radiationSTS-133plant seedssporesbacteriaGerman Aerospace CenterUnited StatesUniverseorganic compoundsosmophilicmeteoritesgenetic materialT7 phagecrustaceancryptobioticmethaneAtmosphere of Titansaturated hydrocarbonsaminoacidshydrocarbon chainnucleobasespolycyclic aromatic hydrocarbonsfullerenesheteroatomsendolithic habitatsBIOPAN5,6-dihydro-5(α-thyminyl)thymineTrichoderma longibrachiatumbacteriophage T7uracilTomatodormant forms of plantsProgress M-24MZvezdacyanobacteriumDeinococcus geothermalisKombuchabiomoleculesbiological pigmentsbiosignatureantibodiesaptamerscarotenoid