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 collection and exposure phase took place from May 2015 through February 2018 utilizing the Exposed Facility located on the exterior of Kibo, the Japanese Experimental Module of the International Space Station. [1] The mission, designed and performed by Japan, used ultra-low density silica gel (aerogel) to collect cosmic dust by, [2] which is being analyzed for amino acid-related compounds and microorganisms following their return to Earth. [3] The last samples were retrieved in February 2018 and analyses are ongoing. [4] The principal investigator is Akihiko Yamagishi, who heads a team of researchers from 26 universities and institutions in Japan, including JAXA.
The capture and exposure experiments in the Tanpopo mission were designed to confirm the hypothesis that extraterrestrial organic compounds played important roles in the generation of the first terrestrial life, as well as examination of the hypothesis of panspermia. If the Tanpopo mission can detect microbes at the higher altitude of low Earth orbit (400 km), it will support the possible interplanetary migration of terrestrial life. [5] [6] The mission was named after the plant dandelion (Tanpopo) because the plant's seeds evoke the image of seeds of lifeforms spreading out through space.
The Tanpopo mission exposures took place at the Exposed Facility located on the exterior of the Kibo module of the ISS from May 2015 through February 2018. [4] It collected cosmic dust and exposed dehydrated microorganisms outside the International Space Station while orbiting 400 km (250 mi) above the Earth. These experiments will test some aspects of panspermia, a hypothesis for an exogenesis origin of life distributed by meteoroids, asteroids, comets and cosmic dust. [7] This mission will also test if terrestrial microbes (e.g., aerosols embedding microbial colonies) may be present, even temporarily and in freeze-dried form in the low Earth orbit altitudes. [7]
Three key microorganisms include Deinococcus species: D. radiodurans , D. aerius and D. aetherius. [8] Containers holding yeast and other microbes were also placed outside the Kibo module to examine whether microbes can survive being exposed to the harsh cold environment of outer space. Also, by evaluating retrieved samples of exposed terrestrial microbes and astronomical organic analogs on the exposure panels, they can investigate their survival and any alterations in the duration of interplanetary transport.
Researchers also aim to capture organic compounds and prebiotic organic compounds — such as aminoacids — drifting in space. [9] The mission collected cosmic dust and other particles for three years by using a two-layer aerogel ultra-low density silica gel collector with a density of 0.01 g/cc (0.0058 oz/cu in) for the upper layer and ~0.03 g/cc (0.017 oz/cu in) for the base layer. [7] Some of the aerogel collectors were replaced every one to two years through February 2018. [9] [4]
The official ISS experiment code name is "Astrobiology Japan" representing "Astrobiology exposure and micrometeoroid capture experiments". [10]
The objectives of Tanpopo lie in following 6 topics: [11]
The aerogels were placed and retrieved by using the robotic arm outside Kibo. The first year samples were returned to Earth in mid-2016, [12] panels from the second year were brought back in late 2017, and the last set ended exposure in February 2018. [4] The last aerogels were placed inside the 'landing & return capsule' in early 2018 and ejected toward Earth for retrieval. [7] After retrieving the aerogels, scientists are investigating the captured microparticles and tracks formed, followed by microbiological, organochemical and mineralogical analyses. Particles potentially containing microbes will be used for PCR amplification of rRNA genes followed by DNA sequencing. [13]
Early mission results from the first sample show evidence that some clumps of microorganism can survive for at least one year in space. [14] This may support the idea that clumps greater than 0.5 millimeters of microorganisms could be one way for life to spread from planet to planet. [14] It was also noted that glycine's decomposition was less than expected, while hydantoin's recovery was much lower than glycine. [3]
In August 2020, scientists reported that bacteria from Earth, particularly Deinococcus radiodurans bacteria, which is highly resistant to environmental hazards, were found to survive for three years in outer space, based on studies conducted on the International Space Station. These findings support the notion of panspermia, the hypothesis that life exists throughout the Universe, distributed in various ways, including space dust, meteoroids, asteroids, comets, planetoids or contaminated spacecraft. [15] [16]
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.
Panspermia is the hypothesis that life exists throughout the Universe, distributed by space dust, meteoroids, asteroids, comets, and planetoids, as well as by spacecraft carrying unintended contamination by microorganisms, known as directed panspermia. The theory argues that life did not originate on Earth, but instead evolved somewhere else and seeded life as we know it.
A micrometeoroid is a tiny meteoroid: a small particle of rock in space, usually weighing less than a gram. A micrometeorite is such a particle that survives passage through Earth's atmosphere and reaches Earth's surface.
Nalin Chandra Wickramasinghe is a Sri Lankan-born British mathematician, astronomer and astrobiologist of Sinhalese ethnicity. His research interests include the interstellar medium, infrared astronomy, light scattering theory, applications of solid-state physics to astronomy, the early Solar System, comets, astrochemistry, the origin of life and astrobiology. A student and collaborator of Fred Hoyle, the pair worked jointly for over 40 years as influential proponents of panspermia. In 1974 they proposed the hypothesis that some dust in interstellar space was largely organic, later proven to be correct.
The Mir Environmental Effects Payload (MEEP) was a set of four experiments installed on the Russian space station Mir from March 1996 to October 1997 to study the effects of space debris impacts and exposure to the space environment on a variety of materials. The materials used in the experiments were being considered for use on the International Space Station, and by exposing them at a similar orbital altitude to that flown by the ISS, the experiments provided an assessment of the performance of those materials in a similar space environment. MEEP also fulfilled the need to examine the occurrence and effects of man-made debris and natural micrometeoroids through capture and impact studies. The experiments were installed on the Mir docking module during STS-76, and retrieved during STS-86.
Astronautical hygiene evaluates, and mitigates, hazards and health risks to those working in low-gravity environments. The discipline of astronautical hygiene includes such topics as the use and maintenance of life support systems, the risks of the extravehicular activity, the risks of exposure to chemicals or radiation, the characterization of hazards, human factor issues, and the development of risk management strategies. Astronautical hygiene works side by side with space medicine to ensure that astronauts are healthy and safe when working in 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.
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.
The Living Interplanetary Flight Experiment was an interplanetary mission developed by the Planetary Society. It consisted of sending selected microorganisms on a three-year interplanetary round-trip in a small capsule aboard the Russian Fobos-Grunt spacecraft in 2011, which was a failed sample-return mission to the Martian moon Phobos. The Fobos-Grunt mission failed to leave Earth orbit and was destroyed.
Deinococcus radiodurans is a bacterium, an extremophile and one of the most radiation-resistant organisms known. It can survive cold, dehydration, vacuum, and acid, and therefore is known as a polyextremophile. The Guinness Book Of World Records listed it in January 1998 as the world's most radiation-resistant bacterium or lifeform.
The O/OREOS is a NASA automated CubeSat nanosatellite laboratory approximately the size of a loaf of bread that contains two separate astrobiology experiments on board. Developed by the Small Spacecraft Division at NASA Ames Research Center, the spacecraft was successfully launched as a secondary payload on STP-S26 led by the Space Test Program of the United States Air Force on a Minotaur IV launch vehicle from Kodiak Island, Alaska on 20 November 2010, at 01:25:00 UTC.
Interplanetary contamination refers to biological contamination of a planetary body by a space probe or spacecraft, either deliberate or unintentional.
Directed panspermia is the deliberate transport of microorganisms into space to be used as introduced species on other astronomical objects.
BIOPAN is a multi-user research program by the European Space Agency (ESA) designed to investigate the effect of the space environment on biological material. The experiments in BIOPAN are exposed to solar and cosmic radiation, the space vacuum and weightlessness, or a selection thereof. Optionally, the experiment temperature can be stabilized. BIOPAN hosts astrobiology, radiobiology and materials science experiments.
Exobiology Radiation Assembly (ERA) was an experiment that investigated the biological effects of space radiation. An astrobiology mission developed by the European Space Agency (ESA), it took place aboard the European Retrievable Carrier (EURECA), an unmanned 4.5 tonne satellite with a payload of 15 experiments.
OREOcube is an experiment designed by the European Space Agency (ESA) with the NASA that will investigate the effects of solar and cosmic radiation on selected organic compounds. It will consist in a 12-month orbital study of the effects of the outer space environment on astrobiologically relevant materials in an external exposure facility on the International Space Station (ISS).
BioSentinel is a lowcost CubeSat spacecraft on a astrobiology mission that will use budding yeast to detect, measure, and compare the impact of deep space radiation on DNA repair over long time beyond low Earth orbit.
Exposing Microorganisms in the Stratosphere (E-MIST) is a NASA study to determine if a specific microorganism could survive conditions like those on the planet Mars. The study transported Bacillus pumilus bacteria and their spores by helium-filled balloon to the stratosphere of Earth and monitored the ability of the microorganisms to survive in extreme Martian-like conditions such as low pressure, dryness, cold, and ionizing radiation.
Astro microbiology, or exo microbiology, is the study of microorganisms in outer space. It stems from an interdisciplinary approach, which incorporates both microbiology and astrobiology. Astrobiology's efforts are aimed at understanding the origins of life and the search for life other than on Earth. Because microorganisms are the most widespread form of life on Earth, and are capable of colonising almost any environment, scientists usually focus on microbial life in the field of astrobiology. Moreover, small and simple cells usually evolve first on a planet rather than larger, multicellular organisms, and have an increased likelihood of being transported from one planet to another via the panspermia theory.