Microgravity

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Researchers at the Indian Institute of Space Science and Technology (IIST) have developed a 3D computational model that shows microgravity consistently increases human core body temperature, which is crucial for long-duration space missions.

What is Microgravity?

• Microgravity is a condition of apparent weightlessness experienced in space when objects are in free-fall orbit around Earth.
• Microgravity does not mean the absence of gravity. At orbital altitudes (~250 miles above Earth), gravity is ~89% as strong as on Earth.
• Objects appear to float because they are in continuous free fall around the Earth, a state first explained by Isaac Newton's orbiting cannonball thought experiment.
• Weightlessness ≠ no gravity; rather, it results from free-fall motion, where objects, spacecraft, and astronauts all fall simultaneously.
• In such an environment, physiological changes occur, affecting bones, muscles, blood circulation, metabolism, and thermoregulation.
• Thermoregulation is the process by which the human body maintains a stable core temperature. It is crucial during long-duration space travel, where the microgravity environment significantly alters normal physiological responses.

Thermoregulation Model

• IIST's Thermoregulation Model: Developed a 3D computational model to simulate how heat moves through the human body under microgravity.
• Incorporates sweating, shivering, clothing effects, organ heat, and blood redistribution to simulate real conditions.
• Key findings of the model include:
  • Hands and feet become cooler in space over time.
  • Head, abdomen, and core body regions become warmer.
  • During exercise in space, the body temperature rises faster than it does on Earth.
  • Core body temperature can rise from 36.3°C to 37.8°C in 2.5 months of microgravity exposure.
  • With exercise, the temperature may rise to nearly 40°C, a potentially dangerous level.
• The model’s accuracy was validated using past data from astronauts onboard the Mir Space Station and the International Space Station (ISS). The predicted results matched historical observations.
• The model also estimates the Universal Thermal Climate Index (UTCI), which reflects how hot or cold it feels outside by factoring in wind, humidity, and solar radiation.

Microgravity FAQs

Q1: What is microgravity?
Ans: Microgravity refers to a condition of very weak gravity, typically experienced in orbiting spacecraft, where objects appear to be weightless and fall at the same rate as the spacecraft.

Q2: How is microgravity different from zero gravity?
Ans: Microgravity is a near-zero gravity condition, while zero gravity is an idealised, absolute absence of gravity, which does not exist in practical terms.

Source: TH