Hazards of Space Travel

• Astronauts face eight hazards during space journeys, and NASA is working to find ways to overcome these challenges for missions to the space station, Moon, Mars, and beyond.

Weightlessness or Microgravity

• Weight, also known as gravity, is the attraction between Earth and an object.
• Gravity is very weak in space, leading to weightlessness or microgravity.
• In space, liquids do not pour without gravity, so astronauts cannot drink from a glass.
• Anything not fastened inside a spacecraft will float, including the astronauts themselves.
• Astronauts wear space suits connected to the spacecraft when outside, to prevent floating too far away.
• Floating weightlessly within a spacecraft can cause dizziness, bone and muscle loss, and vision issues.

Radiation from Space (Cosmic Radiation)

• Earth's magnetic field and atmosphere shield the planet from most space radiation.
• Everyone on Earth is exposed to low levels of radiation daily.
• Astronauts in space face varied and increased radiation levels compared to those on Earth.
• Three sources contributing to space radiation are particles trapped in Earth's magnetic field, solar energetic particles from the Sun, and galactic cosmic rays.
• Space radiation is invisible and considered a hazardous aspect of spaceflight.
• Spacecraft walls can protect astronauts from harmful rays under normal conditions.
• Astronauts wear specially designed space suits for spacewalks for protection.
• Beyond Low Earth Orbit, space radiation can significantly increase the risk of radiation sickness, cancer, central nervous system effects, and degenerative diseases.

Temperature and Pressure

• Earth's temperature typically ranges from 16 to 27 degrees Celsius.
• Space temperature is not in the right range; spacecraft moving close to the sun become very hot, while moving further away becomes very cold.
• Temperature must be carefully controlled within a spacecraft due to temperature extremes being dangerous.

Food

• Early space exploration required astronauts to consume specially designed food squeezed from containers directly into their mouths.
• Modern technology allows astronauts to bring selected regular food into space.

Oxygen

• Humans need oxygen, which is not naturally available in space.
• Astronauts must bring a supply of oxygen into space.
• The amount of oxygen needed depends on how long the astronauts will be in space.

Isolation & Confinement

• Expedition crews are carefully selected, trained, and supported to work effectively as a team for 6- to 12-month missions on the space station.
• Moon or Mars mission crews face more rigorous assessment, selection, and preparation due to longer travel in isolated environments.
• NASA studies people in isolated environments to develop methods and technologies to counteract potential problems.
• Astronauts keep journals to express frustrations and provide insights into behavioral problems related to isolation.
• Virtual reality is being explored to simulate relaxing environments and improve the mood of isolated crews.
• Meaningful activities, like learning a language or new medical skills, can help prevent depression and boost morale.
• Crews may tend to a space garden for positive behavioral health benefits, a fresh food source, and air purification.

Distance from Earth

• The space station orbits 240 miles above Earth.
• The Moon is 1,000 times farther from Earth than the space station.
• Mars is about 140 million miles from Earth.
• Communication with Mars has a one-way delay of up to 20 minutes, requiring astronauts to solve problems independently.
• Considerations for multi-year trips include packing enough food and medicine, since there is no access to stores, like on Earth.
• Unlike space station crews, Mars-bound astronauts must bring all necessary supplies.
• NASA uses space station experiences to understand medical events, skills, procedures, equipment, and supply needs for future Moon and Mars missions.
• Astronauts on the space station receive medical training before and during missions, including using equipment to produce intravenous (IV) solutions from purified water.
• Crew members conduct ultrasound scans on each other to monitor organ health.
• Crews are trained to perform laboratory testing to diagnose and guide treatment if a crew member gets sick.
• NASA studies and improves food formulation, processing, packaging, and preservation to ensure stable nutrients and acceptable food for years.
• Space-resilient medications and packaging systems are essential for preserving pharmaceutical integrity during long-duration missions.

Hostile/Closed Environments

• The ecosystem inside a spacecraft affects astronauts.
• Microbes can change in space, and microorganisms on the human body transfer more easily in closed habitats like the space station.
• NASA monitors air quality in the space station to ensure it is safe to breathe and free from gases.
• Thermal Control Systems regulate the temperature and keep astronauts comfortable.
• Astronauts receive flu shots and quarantine before missions to minimize illness exposure.
• Crews replace air filters, clean surfaces, and treat water to prevent contamination-related illnesses.
• Living and working spaces are planned and evaluated for comfort and efficiency.
• The space station uses LED lighting to mimic natural Earth lighting.

How Space Affects the Human Body

• The force of gravity is weaker, resulting in several changes in human body.
• "Space sickness," including headaches, nausea, and vomiting can occur.
• Radiation doses are higher, potentially causing cataracts, DNA damage, and increased cancer risk.
• Muscles lose mass and strength without the need to support the body against gravity.
• Bones lose density and strength because they are not bearing weight; astronauts can lose up to 1.5% of their bone mass each month, compared to a normal loss of about 1% per year for adults over 50.