1. Humans in Space
SPACE

2. Learning Goals
To be able to explain how humans function in space

3. Feeling of Weightlessness
Most people think weightlessness is caused by a lack of gravity
The force of gravity 100 km above Earth’s surface is 97% of the force at Earth’s surface
Weightlessness occurs because the astronauts are constantly falling towards Earth at the same rate as their spacecraft
This affects the body and causes Space Adaptation Syndrome (SAS)

4. Effects on Humans
Dizziness – about 2/3 of astronauts experience dizziness, disorientation, and nausea during their first few days due to constantly falling
Important tasks such as space walks or docking with the ISS do not take place in the first few days so astronauts can adapt

5. Effects on Humans
Puffy Face and Skinny Legs – on Earth, blood and other body fluids distribute evenly; when in orbit, these fluids collect in the upper parts of the body because of the constant falling motion
This causes puffy face, stuffy nose, headaches, and legs to become skinny
Space travel also affects the body’s use of water and can cause dehydration

6. Effects on Humans
Bone and Muscle Loss – astronauts can lose up to 2% of their bone mass for each month spent in space
This is because the skeletal system does not have to hold up their bodies and leads to a condition similar to osteoporosis
Muscles also weaken so astronauts use a treadmill for at least 2 hours a day
Astronauts can grow 2 to 4 cm because the backbone does not compress as much
Readapting to Earth takes about as long as the astronaut was in space

7. Hazards in Space
Radiation – Earth’s atmosphere and magnetic field protects us from the Sun’s radiation
In low Earth orbit, astronauts can be exposed to harmful radiation
The Space Shuttle and spacesuits are designed with shields to protect astronauts
On missions farther away from Earth, radiation exposure has to be monitored closely

8. Hazards in Space
Environmental System Failure – life support systems are essential to maintaining the survival of astronauts
Computer Failure – spacecraft are operated by computers; Space Shuttle has 5 computers that “vote” to make sure the correct decision is made
Loss of Communication – Mission Control Center guides spacecraft through re-entry; “go home plan” is updated each day

9. Living in Space On the ISS, electricity is generated from solar panels
Oxygen comes from electrolysis, breaking down water
Water is recycled as much as possible
Food is dehydrated (dried out) then rehydrated and heated in microwaves
Astronauts use footholds to stay in place and are strapped down to floors, walls, or ceilings when sleeping

10. Working in Space
Microgravity – an environment in which objects behave as though there is very little gravity affecting them
Astronauts train in water tanks on Earth
Tools must be precise and suited for 100°C environments with no air, and must be tethered to something with a long cord
November 2008, an astronaut let go of a backpack sized tool bag worth $100,000, which was spotted in the night sky, now burned up

11. Technology Transfer – Why Go to Space?
Canadarm technology is used in artificial limbs, to clean up harmful wastes, and to perform surgery (without leaving large incisions)
GPS (Global Positioning System) – a network of 30 satellites orbit Earth; at least 4 satellites send signals to identify specific locations
Many items were originally developed for use in space – bar codes, beverage coolers, cordless tools, lightweight shoes

16. Success Criteria I CAN describe how humans live and work in space
I CAN describe some of the hazards human face in space