Response of Terrestrial Life to Space Conditions

A special issue of Life (ISSN 2075-1729). This special issue belongs to the section "Astrobiology".

Deadline for manuscript submissions: closed (15 January 2014) | Viewed by 160903

Special Issue Editor


E-Mail Website
Guest Editor
Aerospace Engineering Sciences, University of Colorado, Boulder, CO 80309, USA
Interests: bioastronautics; human space flight; spacecraft life support systems; spacesuit technologies; gravitational biology; extracellular mass transport

Special Issue Information

Dear Colleagues,

Life as we know it on Earth has evolved in the presence of terrestrial gravity while protected under an atmosphere and a magnetic field that both help to keep harmful radiation exposure at sufficiently low levels. These ubiquitous physical factors greatly influence the morphology and behavior of living systems ranging from the smallest microbes to plant life and up to humans. The force of gravity dictates the need for load-bearing structures and creates hydrostatic gradients in liquids that are contained within organisms. Similarly, orientation and locomotion on the surface, in water, or through air must also overcome the constant downward force exerted by Earth's gravitational attraction. All of these physical attributes are altered when an organism is exposed to conditions of spaceflight, where the orbital state of free fall results in a weightless environment. For small microbes, weightlessness alters biophysical interactions and affects cell population distribution in suspension cultures. Plants no longer need the same degree of structural provision to support their weight, nor do they have the ability to properly orient their roots and shoots upon initial emergence from seed. Humans suffer from bone and muscle disuse atrophy, as well as experience neurovestibular disorientation and a cephalic fluid shift that sets up a number of subsequent adaptive physiological responses. Research is aimed at better characterizing, perhaps even utilizing, these altered biological outcomes, and also at developing countermeasures in an attempt to counteract those effects that are exceedingly detrimental. Planetary surface exploration introduces various additional concerns. Furthermore, as humans venture beyond Low Earth Orbit and out past the Van Allen Belts, chronic exposure to galactic cosmic radiation increases and potentially lethal, acute solar events pose serious threats to life at all levels. The submission of scientific perspectives, comprehensive reviews or research articles on these and related topics is welcome for this special edition.

Prof. David M. Klaus
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Life is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.


Keywords

  • bioastronautics
  • gravitational biology
  • gravitropism
  • life in space
  • microgravity
  • radiation biology
  • space life sciences
  • space medicine
  • space physiology
  • spaceflight biomedical countermeasures
  • spaceflight biotechnology

Published Papers (13 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Jump to: Review

453 KiB  
Communication
Effects of the Extraterrestrial Environment on Plants: Recommendations for Future Space Experiments for the MELiSSA Higher Plant Compartment
by Silje A. Wolff, Liz H. Coelho, Irene Karoliussen and Ann-Iren Kittang Jost
Life 2014, 4(2), 189-204; https://doi.org/10.3390/life4020189 - 05 May 2014
Cited by 37 | Viewed by 11421
Abstract
Due to logistical challenges, long-term human space exploration missions require a life support system capable of regenerating all the essentials for survival. Higher plants can be utilized to provide a continuous supply of fresh food, atmosphere revitalization, and clean water for humans. Plants [...] Read more.
Due to logistical challenges, long-term human space exploration missions require a life support system capable of regenerating all the essentials for survival. Higher plants can be utilized to provide a continuous supply of fresh food, atmosphere revitalization, and clean water for humans. Plants can adapt to extreme environments on Earth, and model plants have been shown to grow and develop through a full life cycle in microgravity. However, more knowledge about the long term effects of the extraterrestrial environment on plant growth and development is necessary. The European Space Agency (ESA) has developed the Micro-Ecological Life Support System Alternative (MELiSSA) program to develop a closed regenerative life support system, based on micro-organisms and higher plant processes, with continuous recycling of resources. In this context, a literature review to analyze the impact of the space environments on higher plants, with focus on gravity levels, magnetic fields and radiation, has been performed. This communication presents a roadmap giving directions for future scientific activities within space plant cultivation. The roadmap aims to identify the research activities required before higher plants can be included in regenerative life support systems in space. Full article
(This article belongs to the Special Issue Response of Terrestrial Life to Space Conditions)
Show Figures

Figure 1

1446 KiB  
Article
Cineradiographic Analysis of Mouse Postural Response to Alteration of Gravity and Jerk (Gravity Deceleration Rate)
by Katsuya Hasegawa, Priscila S. De Campos, Jorge L. Zeredo and Yasuhiro Kumei
Life 2014, 4(2), 174-188; https://doi.org/10.3390/life4020174 - 24 Apr 2014
Cited by 5 | Viewed by 7159
Abstract
The ability to maintain the body relative to the external environment is important for adaptation to altered gravity. However, the physiological limits for adaptation or the disruption of body orientation are not known. In this study, we analyzed postural changes in mice upon [...] Read more.
The ability to maintain the body relative to the external environment is important for adaptation to altered gravity. However, the physiological limits for adaptation or the disruption of body orientation are not known. In this study, we analyzed postural changes in mice upon exposure to various low gravities. Male C57BL6/J mice (n = 6) were exposed to various gravity-deceleration conditions by customized parabolic flight-maneuvers targeting the partial-gravity levels of 0.60, 0.30, 0.15 and μ g (<0.001 g). Video recordings of postural responses were analyzed frame-by-frame by high-definition cineradiography and with exact instantaneous values of gravity and jerk. As a result, the coordinated extension of the neck, spine and hindlimbs was observed during the initial phase of gravity deceleration. Joint angles widened to 120%–200% of the reference g level, and the magnitude of the thoracic-curvature stretching was correlated with gravity and jerk, i.e., the gravity deceleration rate. A certain range of jerk facilitated mouse skeletal stretching efficiently, and a jerk of −0.3~−0.4 j (g/s) induced the maximum extension of the thoracic-curvature. The postural response of animals to low gravity may undergo differential regulation by gravity and jerk. Full article
(This article belongs to the Special Issue Response of Terrestrial Life to Space Conditions)
Show Figures

Figure 1

565 KiB  
Article
Neuronal Activity in the Subthalamic Cerebrovasodilator Area under Partial-Gravity Conditions in Rats
by Zeredo L Zeredo, Kazuo Toda and Yasuhiro Kumei
Life 2014, 4(1), 107-116; https://doi.org/10.3390/life4010107 - 04 Mar 2014
Cited by 3 | Viewed by 6429
Abstract
The reduced-gravity environment in space is known to cause an upward shift in body fluids and thus require cardiovascular adaptations in astronauts. In this study, we recorded in rats the neuronal activity in the subthalamic cerebrovasodilator area (SVA), a key area that controls [...] Read more.
The reduced-gravity environment in space is known to cause an upward shift in body fluids and thus require cardiovascular adaptations in astronauts. In this study, we recorded in rats the neuronal activity in the subthalamic cerebrovasodilator area (SVA), a key area that controls cerebral blood flow (CBF), in response to partial gravity. “Partial gravity” is the term that defines the reduced-gravity levels between 1 g (the unit gravity acceleration on Earth) and 0 g (complete weightlessness in space). Neuronal activity was recorded telemetrically through chronically implanted microelectrodes in freely moving rats. Graded levels of partial gravity from 0.4 g to 0.01 g were generated by customized parabolic-flight maneuvers. Electrophysiological signals in each partial-gravity phase were compared to those of the preceding 1 g level-flight. As a result, SVA neuronal activity was significantly inhibited by the partial-gravity levels of 0.15 g and lower, but not by 0.2 g and higher. Gravity levels between 0.2–0.15 g could represent a critical threshold for the inhibition of neurons in the rat SVA. The lunar gravity (0.16 g) might thus trigger neurogenic mechanisms of CBF control. This is the first study to examine brain electrophysiology with partial gravity as an experimental parameter. Full article
(This article belongs to the Special Issue Response of Terrestrial Life to Space Conditions)
Show Figures

Figure 1

226 KiB  
Article
Distance and Size Perception in Astronauts during Long-Duration Spaceflight
by Gilles Clément, Anna Skinner and Corinna Lathan
Life 2013, 3(4), 524-537; https://doi.org/10.3390/life3040524 - 13 Dec 2013
Cited by 46 | Viewed by 9502
Abstract
Exposure to microgravity during spaceflight is known to elicit orientation illusions, errors in sensory localization, postural imbalance, changes in vestibulo-spinal and vestibulo-ocular reflexes, and space motion sickness. The objective of this experiment was to investigate whether an alteration in cognitive visual-spatial processing, such [...] Read more.
Exposure to microgravity during spaceflight is known to elicit orientation illusions, errors in sensory localization, postural imbalance, changes in vestibulo-spinal and vestibulo-ocular reflexes, and space motion sickness. The objective of this experiment was to investigate whether an alteration in cognitive visual-spatial processing, such as the perception of distance and size of objects, is also taking place during prolonged exposure to microgravity. Our results show that astronauts on board the International Space Station exhibit biases in the perception of their environment. Objects’ heights and depths were perceived as taller and shallower, respectively, and distances were generally underestimated in orbit compared to Earth. These changes may occur because the perspective cues for depth are less salient in microgravity or the eye-height scaling of size is different when an observer is not standing on the ground. This finding has operational implications for human space exploration missions. Full article
(This article belongs to the Special Issue Response of Terrestrial Life to Space Conditions)
Show Figures

Figure 1

Review

Jump to: Research

4364 KiB  
Review
Microgravity-Induced Fluid Shift and Ophthalmic Changes
by Emily S. Nelson, Lealem Mulugeta and Jerry G. Myers
Life 2014, 4(4), 621-665; https://doi.org/10.3390/life4040621 - 07 Nov 2014
Cited by 117 | Viewed by 20612
Abstract
Although changes to visual acuity in spaceflight have been observed in some astronauts since the early days of the space program, the impact to the crew was considered minor. Since that time, missions to the International Space Station have extended the typical duration [...] Read more.
Although changes to visual acuity in spaceflight have been observed in some astronauts since the early days of the space program, the impact to the crew was considered minor. Since that time, missions to the International Space Station have extended the typical duration of time spent in microgravity from a few days or weeks to many months. This has been accompanied by the emergence of a variety of ophthalmic pathologies in a significant proportion of long-duration crewmembers, including globe flattening, choroidal folding, optic disc edema, and optic nerve kinking, among others. The clinical findings of affected astronauts are reminiscent of terrestrial pathologies such as idiopathic intracranial hypertension that are characterized by high intracranial pressure. As a result, NASA has placed an emphasis on determining the relevant factors and their interactions that are responsible for detrimental ophthalmic response to space. This article will describe the Visual Impairment and Intracranial Pressure syndrome, link it to key factors in physiological adaptation to the microgravity environment, particularly a cephalad shifting of bodily fluids, and discuss the implications for ocular biomechanics and physiological function in long-duration spaceflight. Full article
(This article belongs to the Special Issue Response of Terrestrial Life to Space Conditions)
Show Figures

Graphical abstract

4014 KiB  
Review
Space Radiation: The Number One Risk to Astronaut Health beyond Low Earth Orbit
by Jeffery C. Chancellor, Graham B. I. Scott and Jeffrey P. Sutton
Life 2014, 4(3), 491-510; https://doi.org/10.3390/life4030491 - 11 Sep 2014
Cited by 268 | Viewed by 33744
Abstract
Projecting a vision for space radiobiological research necessitates understanding the nature of the space radiation environment and how radiation risks influence mission planning, timelines and operational decisions. Exposure to space radiation increases the risks of astronauts developing cancer, experiencing central nervous system (CNS) [...] Read more.
Projecting a vision for space radiobiological research necessitates understanding the nature of the space radiation environment and how radiation risks influence mission planning, timelines and operational decisions. Exposure to space radiation increases the risks of astronauts developing cancer, experiencing central nervous system (CNS) decrements, exhibiting degenerative tissue effects or developing acute radiation syndrome. One or more of these deleterious health effects could develop during future multi-year space exploration missions beyond low Earth orbit (LEO). Shielding is an effective countermeasure against solar particle events (SPEs), but is ineffective in protecting crew members from the biological impacts of fast moving, highly-charged galactic cosmic radiation (GCR) nuclei. Astronauts traveling on a protracted voyage to Mars may be exposed to SPE radiation events, overlaid on a more predictable flux of GCR. Therefore, ground-based research studies employing model organisms seeking to accurately mimic the biological effects of the space radiation environment must concatenate exposures to both proton and heavy ion sources. New techniques in genomics, proteomics, metabolomics and other “omics” areas should also be intelligently employed and correlated with phenotypic observations. This approach will more precisely elucidate the effects of space radiation on human physiology and aid in developing personalized radiological countermeasures for astronauts. Full article
(This article belongs to the Special Issue Response of Terrestrial Life to Space Conditions)
Show Figures

Figure 1

736 KiB  
Review
Protein and Essential Amino Acids to Protect Musculoskeletal Health during Spaceflight: Evidence of a Paradox?
by Kyle J. Hackney and Kirk L. English
Life 2014, 4(3), 295-317; https://doi.org/10.3390/life4030295 - 11 Jul 2014
Cited by 16 | Viewed by 7487
Abstract
Long-duration spaceflight results in muscle atrophy and a loss of bone mineral density. In skeletal muscle tissue, acute exercise and protein (e.g., essential amino acids) stimulate anabolic pathways (e.g., muscle protein synthesis) both independently and synergistically to maintain neutral or positive net muscle [...] Read more.
Long-duration spaceflight results in muscle atrophy and a loss of bone mineral density. In skeletal muscle tissue, acute exercise and protein (e.g., essential amino acids) stimulate anabolic pathways (e.g., muscle protein synthesis) both independently and synergistically to maintain neutral or positive net muscle protein balance. Protein intake in space is recommended to be 12%–15% of total energy intake (≤1.4 g∙kg1∙day1) and spaceflight is associated with reduced energy intake (~20%), which enhances muscle catabolism. Increasing protein intake to 1.5–2.0 g∙kg1∙day1 may be beneficial for skeletal muscle tissue and could be accomplished with essential amino acid supplementation. However, increased consumption of sulfur-containing amino acids is associated with increased bone resorption, which creates a dilemma for musculoskeletal countermeasures, whereby optimizing skeletal muscle parameters via essential amino acid supplementation may worsen bone outcomes. To protect both muscle and bone health, future unloading studies should evaluate increased protein intake via non-sulfur containing essential amino acids or leucine in combination with exercise countermeasures and the concomitant influence of reduced energy intake. Full article
(This article belongs to the Special Issue Response of Terrestrial Life to Space Conditions)
917 KiB  
Review
Cognitive Neuroscience in Space
by Gabriel G. De la Torre
Life 2014, 4(3), 281-294; https://doi.org/10.3390/life4030281 - 03 Jul 2014
Cited by 69 | Viewed by 15499
Abstract
Humans are the most adaptable species on this planet, able to live in vastly different environments on Earth. Space represents the ultimate frontier and a true challenge to human adaptive capabilities. As a group, astronauts and cosmonauts are selected for their ability to [...] Read more.
Humans are the most adaptable species on this planet, able to live in vastly different environments on Earth. Space represents the ultimate frontier and a true challenge to human adaptive capabilities. As a group, astronauts and cosmonauts are selected for their ability to work in the highly perilous environment of space, giving their best. Terrestrial research has shown that human cognitive and perceptual motor performances deteriorate under stress. We would expect to observe these effects in space, which currently represents an exceptionally stressful environment for humans. Understanding the neurocognitive and neuropsychological parameters influencing space flight is of high relevance to neuroscientists, as well as psychologists. Many of the environmental characteristics specific to space missions, some of which are also present in space flight simulations, may affect neurocognitive performance. Previous work in space has shown that various psychomotor functions degrade during space flight, including central postural functions, the speed and accuracy of aimed movements, internal timekeeping, attentional processes, sensing of limb position and the central management of concurrent tasks. Other factors that might affect neurocognitive performance in space are illness, injury, toxic exposure, decompression accidents, medication side effects and excessive exposure to radiation. Different tools have been developed to assess and counteract these deficits and problems, including computerized tests and physical exercise devices. It is yet unknown how the brain will adapt to long-term space travel to the asteroids, Mars and beyond. This work represents a comprehensive review of the current knowledge and future challenges of cognitive neuroscience in space from simulations and analog missions to low Earth orbit and beyond. Full article
(This article belongs to the Special Issue Response of Terrestrial Life to Space Conditions)
Show Figures

Figure 1

600 KiB  
Review
Stem Cells toward the Future: The Space Challenge
by Silvia Bradamante, Livia Barenghi and Jeanette A.M. Maier
Life 2014, 4(2), 267-280; https://doi.org/10.3390/life4020267 - 30 May 2014
Cited by 22 | Viewed by 9290
Abstract
Astronauts experience weightlessness-induced bone loss due to an unbalanced process of bone remodeling that involves bone mesenchymal stem cells (bMSCs), as well as osteoblasts, osteocytes, and osteoclasts. The effects of microgravity on osteo-cells have been extensively studied, but it is only recently that [...] Read more.
Astronauts experience weightlessness-induced bone loss due to an unbalanced process of bone remodeling that involves bone mesenchymal stem cells (bMSCs), as well as osteoblasts, osteocytes, and osteoclasts. The effects of microgravity on osteo-cells have been extensively studied, but it is only recently that consideration has been given to the role of bone MSCs. These live in adult bone marrow niches, are characterized by their self-renewal and multipotent differentiation capacities, and the published data indicate that they may lead to interesting returns in the biomedical/bioengineering fields. This review describes the published findings concerning bMSCs exposed to simulated/real microgravity, mainly concentrating on how mechanosignaling, mechanotransduction and oxygen influence their proliferation, senescence and differentiation. A comprehensive understanding of bMSC behavior in microgravity and their role in preventing bone loss will be essential for entering the future age of long-lasting, manned space exploration. Full article
(This article belongs to the Special Issue Response of Terrestrial Life to Space Conditions)
Show Figures

Figure 1

818 KiB  
Review
Host-Microbe Interactions in Microgravity: Assessment and Implications
by Jamie S. Foster, Raymond M. Wheeler and Regine Pamphile
Life 2014, 4(2), 250-266; https://doi.org/10.3390/life4020250 - 26 May 2014
Cited by 26 | Viewed by 10702
Abstract
Spaceflight imposes several unique stresses on biological life that together can have a profound impact on the homeostasis between eukaryotes and their associated microbes. One such stressor, microgravity, has been shown to alter host-microbe interactions at the genetic and physiological levels. Recent sequencing [...] Read more.
Spaceflight imposes several unique stresses on biological life that together can have a profound impact on the homeostasis between eukaryotes and their associated microbes. One such stressor, microgravity, has been shown to alter host-microbe interactions at the genetic and physiological levels. Recent sequencing of the microbiomes associated with plants and animals have shown that these interactions are essential for maintaining host health through the regulation of several metabolic and immune responses. Disruptions to various environmental parameters or community characteristics may impact the resiliency of the microbiome, thus potentially driving host-microbe associations towards disease. In this review, we discuss our current understanding of host-microbe interactions in microgravity and assess the impact of this unique environmental stress on the normal physiological and genetic responses of both pathogenic and mutualistic associations. As humans move beyond our biosphere and undergo longer duration space flights, it will be essential to more fully understand microbial fitness in microgravity conditions in order to maintain a healthy homeostasis between humans, plants and their respective microbiomes. Full article
(This article belongs to the Special Issue Response of Terrestrial Life to Space Conditions)
Show Figures

Figure 1

725 KiB  
Review
Plant Growth and Morphogenesis under Different Gravity Conditions: Relevance to Plant Life in Space
by Takayuki Hoson
Life 2014, 4(2), 205-216; https://doi.org/10.3390/life4020205 - 16 May 2014
Cited by 40 | Viewed by 9954
Abstract
The growth and morphogenesis of plants are entirely dependent on the gravitational acceleration of earth. Under microgravity conditions in space, these processes are greatly modified. Recent space experiments, in combination with ground-based studies, have shown that elongation growth is stimulated and lateral expansion [...] Read more.
The growth and morphogenesis of plants are entirely dependent on the gravitational acceleration of earth. Under microgravity conditions in space, these processes are greatly modified. Recent space experiments, in combination with ground-based studies, have shown that elongation growth is stimulated and lateral expansion suppressed in various shoot organs and roots under microgravity conditions. Plant organs also show automorphogenesis in space, which consists of altered growth direction and spontaneous curvature in the dorsiventral (back and front) directions. Changes in cell wall properties are responsible for these modifications of growth and morphogenesis under microgravity conditions. Plants live in space with interesting new sizes and forms. Full article
(This article belongs to the Special Issue Response of Terrestrial Life to Space Conditions)
Show Figures

Graphical abstract

128 KiB  
Review
The Role of Mechanical Stimulation in Recovery of Bone Loss—High versus Low Magnitude and Frequency of Force
by Mamta Patel Nagaraja and Hanjoong Jo
Life 2014, 4(2), 117-130; https://doi.org/10.3390/life4020117 - 02 Apr 2014
Cited by 38 | Viewed by 8912
Abstract
Musculoskeletal pathologies associated with decreased bone mass, including osteoporosis and disuse-induced bone loss, affect millions of Americans annually. Microgravity-induced bone loss presents a similar concern for astronauts during space missions. Many pharmaceutical treatments have slowed osteoporosis, and recent data shows promise for countermeasures [...] Read more.
Musculoskeletal pathologies associated with decreased bone mass, including osteoporosis and disuse-induced bone loss, affect millions of Americans annually. Microgravity-induced bone loss presents a similar concern for astronauts during space missions. Many pharmaceutical treatments have slowed osteoporosis, and recent data shows promise for countermeasures for bone loss observed in astronauts. Additionally, high magnitude and low frequency impact such as running has been recognized to increase bone and muscle mass under normal but not microgravity conditions. However, a low magnitude and high frequency (LMHF) mechanical load experienced in activities such as postural control, has also been shown to be anabolic to bone. While several clinical trials have demonstrated that LMHF mechanical loading normalizes bone loss in vivo, the target tissues and cells of the mechanical load and underlying mechanisms mediating the responses are unknown. In this review, we provide an overview of bone adaptation under a variety of loading profiles and the potential for a low magnitude loading as a way to counteract bone loss as experienced by astronauts. Full article
(This article belongs to the Special Issue Response of Terrestrial Life to Space Conditions)
112 KiB  
Review
On the Response of Halophilic Archaea to Space Conditions
by Stefan Leuko, Petra Rettberg, Ashleigh L. Pontifex and Brendan P. Burns
Life 2014, 4(1), 66-76; https://doi.org/10.3390/life4010066 - 21 Feb 2014
Cited by 19 | Viewed by 8863
Abstract
Microorganisms are ubiquitous and can be found in almost every habitat and ecological niche on Earth. They thrive and survive in a broad spectrum of environments and adapt to rapidly changing external conditions. It is of great interest to investigate how microbes adapt [...] Read more.
Microorganisms are ubiquitous and can be found in almost every habitat and ecological niche on Earth. They thrive and survive in a broad spectrum of environments and adapt to rapidly changing external conditions. It is of great interest to investigate how microbes adapt to different extreme environments and with modern human space travel, we added a new extreme environment: outer space. Within the last 50 years, technology has provided tools for transporting microbial life beyond Earth’s protective shield in order to study in situ responses to selected conditions of space. This review will focus on halophilic archaea, as, due to their ability to survive in extremes, they are often considered a model group of organisms to study responses to the harsh conditions associated with space. We discuss ground-based simulations, as well as space experiments, utilizing archaea, examining responses and/or resistance to the effects of microgravity and UV in particular. Several halophilic archaea (e.g., Halorubrum chaoviator) have been exposed to simulated and actual space conditions and their survival has been determined as well as the protective effects of halite shown. Finally, the intriguing potential of archaea to survive on other planets or embedded in a meteorite is postulated. Full article
(This article belongs to the Special Issue Response of Terrestrial Life to Space Conditions)
Back to TopTop