A pair of astronauts stranded in space for more than nine months were finally headed home Tuesday after their capsule undocked from the International Space Station. The consequences of such a stay on the body of astronauts are manifold. VIDEOGRAPHIC
Category
🗞
NewsTranscript
00:00For humans, space is a hostile place.
00:10The biggest challenges?
00:12Cosmic radiation and microgravity.
00:16Microgravity affects body functions.
00:19Bone density drops by 1 to 1.5% in a single month, equivalent to that lost by an elderly
00:25person on Earth in one year.
00:30Muscles lose up to 20% of their mass in a few days.
00:35The heart atrophies.
00:36It no longer needs to work so hard to pump blood from the feet to the brain.
00:41Body fluids travel to the head, putting pressure on the brain and eyes.
00:46This can lead to long-term problems with vision.
00:49Other dangers are the effect on arteries.
00:52In just six months, they can age between 20 and 30 years.
00:55Kidney stones are a worry too, because urine contains more calcium, which results in a
01:00reduction in bone density.
01:03The backbone can lengthen up to 5cm, and this increases the risk of slipping a disc.
01:09Humans are protected from cosmic radiation on Earth by the atmosphere, but in space,
01:14it poses a real threat.
01:16Exposure to radiation on the International Space Station is 10 times greater than on
01:21Earth.
01:22It increases the risk of cancer and alters the blood count and the immune system.
01:27The loneliness of spaceflight can also affect morale and cause stress.
01:33It's a lot to cope with, especially on long missions, to Mars for example, when astronauts
01:37could be in space for up to nine months.
01:46NASA Jet Propulsion Laboratory, California Institute of Technology