The Space Environment II Overview of the Space Environment
NATS 1532 - Human Spaceflight: The Space Environment II
Overview of the Space Environment
Key Components:
Gravity
Temperature
Vacuum
Radiation
Orbital Debris
Relevant Images: aeronomie.be
Detailed Examination of the Space Environment
Space Environment for Microbes
Components
Gravity
Temperature
Vacuum
Radiation
Orbital Debris
Planned Focus: How these elements affect microbes specifically
Relevant Images: Government of Canada
Radiation Exposure
Effects of Radiation Exposure
Can cause individual cell damage, mutation, and/or cell death.
Exposure limits for irreversible damage or death vary dramatically from species to species.
Relevant Images: Government of Canada
Space Environment for Non-Microbes
Similar components as microbes:
Gravity
Temperature
Vacuum
Radiation
Orbital Debris
Relevant Images: classnotes.ng
Human Responses in Microgravity
Effects on Humans in Microgravity
Physical and physiological responses to space environment include:
Space Motion Sickness
Redistribution of fluids
Spinal Extension
Muscular Atrophy
Bone Density Loss
Altered Perception of Smell and Taste
Increased risk of Kidney Stones
Illness related to radiation exposure
Tear behavior differences
Relevant Images: NASA
Exploration of Other Complex Lifeforms in Microgravity
Animals in Space
Historical Overview
1942: First lifeforms (fruit flies) sent to space.
Early spacecraft tested on Chimpanzees (NASA) and Dogs (USSR).
1961: First human in space, Yuri Gagarin.
Various species (5 mice, 2 tortoises, several plants) have orbited the Moon.
10 different species have landed on the Moon.
Relevant Images: NASA
Extended Habitation in Space
Many species have spent time onboard satellites, spacecraft, and the ISS (International Space Station).
Specific Studies of Microgravity Effects on Various Species
General Queries on Insights Gained from Microgravity Studies
Spiders
Behavioral and physical traits influenced by gravity:
Web development and prey capturing techniques.
Observation: Spider webs become more chaotic over time in microgravity.
Degree of web asymmetry differs significantly from earthbound spiders.
Relevant Images: Zschokke, Countryman, and Cushing 2020
Asymmetric Spider Webs
Species Example: Trichonephila clavipes
Creates asymmetric webs where:
Spider waits in the top half
Prey becomes stuck in the bottom half
Spider descends to capture
Observation: In microgravity, webs become progressively more symmetric.
Frogs
Anatomy and Behavior
Frogs share similar inner ear structures with humans, playing roles in balance and orientation.
Observed behaviors in microgravity:
Attempt to stabilize themselves using swimming motions.
Exhibit asymmetrical motions.
Behaviors are comparable to frogs experiencing freefall or upside-down on Earth.
Fish
Behavioral Adaptations
Swim in random directions.
Treated light sources as 'up' when provided.
Important for astrobiological studies regarding radiation and microgravity effects.
Fish Bone Density Studies
Subjects: Transparent Medaka Fish
Genetically modified to have glowing cells responsible for breaking down and repairing bone tissue under UV light.
Immediate cellular response to microgravity observed, offering insights into bone density loss.
Relevant Images: JAXA
Fish Reproduction Studies
Species studied: Zebra Fish
Embryos are transparent and develop externally, allowing for continuous development study from fertilization to birth.
Relevant Images: CNSA
Mice in Space
Example of Genetically Modified Mice
Developed with increased muscle mass (Mighty Mice!).
Inhibits specific proteins to minimize bone density and muscle loss in microgravity.
Relevant Images: NASA
Species Not Sent to Space Used for Microgravity Tests
Birds
Observational Challenges
Loss of orientation and ability to fly upside down.
Panic and stress responses.
Cats
Observational Challenges
Loss of orientation demonstrated and absence of typical falling reflex.
Panic and stress responses noted.
Ethical Concerns Surrounding Animal Testing in Space
Plant Growth in the Space Environment
Agricultural Studies in Space
Plants can successfully be grown in space environments given:
Adequate water, atmosphere, nutrients, and proper grow beds.
Sensitivity to microgravity is generally minimal.
Plants utilize light to orient and guide their growth.
Examples cultivated on ISS: Mustard, kale, lettuce, dwarf wheat, Chinese cabbage, zinnia flowers.
Relevant Images: Scott Kelly
Genetic Modifications in Space Agriculture
Aim to optimize plant usefulness and growth efficiency in space:
Example: Manipulating lignin content to improve nutrient absorption and composting ease.
Relevant Images: NASA
Plant Growth on Other Worlds
Investigation of lunar regolith for plant growth:
Nutrients, water, and atmosphere provided for growth.
Results indicate smaller plants with physiological stress versus Earth soil grown plants.
No successful trials of plants grown in simulated Mars soil yet; necessity for treatment/cleaning discussed.
Relevant Images: Paul, Elardo, Furl 2022
Genetically Modified Plants for Other Worlds
Potential for environmental adaptation:
Example: Designing plants for Mars combining cold tolerance of Arctic bacteria with UV resistance of high-altitude tomato plants.
This could create plants that thrive in Martian soil.
Relevant Images: North Carolina State University
Environmental Factors Affecting Life in Space
Temperature Extremes
Earth’s average temperature: 15 °C, with a range of -90 °C to 70 °C
Most species thrive under moderate and stable temperatures.
Low Earth Orbit presents temperatures of -150 °C to 120 °C, lethal for complex lifeforms.
Atmospheric Pressure
Earth life is accustomed to minimal pressure gradients between body and environment.
Vacuum Conditions
Characterized by a high-pressure gradient between outer space and internal body environments.
Consequences of disruption include
Air rushes out of lungs.
Body intends to expand, which is fatal to non-microbial life.
Understanding Radiation Risks
Health Risks from Radiation
Direct effects include
Individual cell damage.
Mutation and cell death.
Adverse impacts on both microbes and complex lifeforms
Conditions caused by radiation exposure:
Radiation syndrome.
Blood alterations, nausea, vomiting.
Cataracts.
Sterility issues.
Increased cancer risk.
Relevant Images: Government of Canada
Exposure Statistics
Earth has inherent protective mechanisms through its magnetic field.
The Sun's magnetic field protects from Galactic cosmic rays.
Radiation exposure for astronauts onboard the ISS is nearly 70 times greater than on Earth's surface.
Interplanetary travel exposes astronauts to over 150 times the radiation levels found on Earth.
Relevant Images: earth.com
Career Dose Limits for Astronauts
Current regulations indicate that career exposure limits should not exceed the equivalent of 10 years aboard the ISS or 4.5 years in interplanetary space.
Additional Hazards
Risks from Orbital Debris
Hypervelocity collisions are a significant concern:
Though most debris is small, their velocity can be 10 times that of a bullet.
Debris larger than 10 cm can disintegrate targets, representing a high threat to spacecraft.
Risks are pronounced for space-walking human-sized life forms, while the risk remains negligible for microbes.
Relevant Images: NASA
Enhancing Space Habitability
Current Mitigation Strategies
Range of strategies aimed at reducing the effects of microgravity on life in space.
Protecting Against Microgravity Conditions
Strategies in place include:
Artificial Gravity beginnings in research (using formulas such as ac = \frac{42R}{T^2}, with ac being 9.8 m/s² and D = 300 m, and T = 25.5 s).
2.5 hours of exercise per day as a standard to minimize muscle atrophy and bone loss.
Use of specialized workout machines designed for muscle engagement.
Importance of hydration and sometimes specialized clothing assists with fluid redistribution and orientation loss.
Visual cues are critical to prevent disorientation in microgravity environments.
Relevant Images: NASA
Protective Measures Against Environmental Hazards
Protection Strategies include:
Shielding from radiation and orbital debris.
Designing pressurized spacecraft or spacesuits.
Monitoring orbital debris to avoid polluted regions in space.
Relevant Images: ESA, NASA
Conclusion on Space as a Life-Threatening Environment
Space is fundamentally hostile to life as currently understood in every conceivable aspect.
Despite the hazards, human presence in space continues to expand.
Future Considerations for Human Space Missions
Anticipated challenges associated with increasing mission duration and complexity.
Issues around radiation exposure and psychological health.
Potential for colonization of other worlds and implications of partial gravity compared to microgravity.
Considerations for reproduction and development in extraterrestrial environments.
Twin Study Overview
Notable research by Astronaut Scott Kelly, who spent a year in space while his twin brother, retired astronaut Mark Kelly, remained on Earth.
Focus: Understanding human adaptation, effects on biological functions, and recovery post-exposure.
Relevant Images: NASA, PBS
Genetic Modifications for Enhanced Space Survival
Considerations for potential genetic enhancements aimed at improving astronaut survival in space environments.
Identified modifications can include resistance to radiation, enhanced bone strength, lower oxygen requirements, cancer resistance, reduced height, and lower odor production.
Relevant Images: Aerospace America
Ethical Concerns Regarding Human Genetic Modifications
Pre-meeting Assignment: Read “Human enhancement in space missions: From moral controversy to technological duty” by Szocika & Wójtowicz available on eClass.