Spending time in space is a perquisite reserved for only a few humans , but it come at a cost : living in microgravity has several negatively charged effects on human physiology .
Not all the event and consequences are completely understood , though . Studying astronaut Scott Kelly , who hasjust returnedfrom a 340 - day mission on the International Space Station ( ISS ) , and compare him to his twin comrade Mark , scientists hope to hear a stack more about how humans can accommodate to living away from Earth . " They ’ll be going through a multifariousness of dissimilar tasks that look a deal like what you might have to do if you had just landed on the surface of Mars , " aver International Space Station Chief Scientist Julie Robinson ina NASA video recording .
Here ’s what we know so far .
Radiation
A significant concern for the astronauts ’ wellness is the dose of radiation . The ISS is within Earth ’s magnetosphere , so astronauts are part shielded from the solar tip , but a year in infinite would still be tantamount to over40 timesthe dose a mortal living in the U.S. is exposed to every year .
The high level of radiation can cause short- and farsighted - terminal figure damages to the ivory inwardness , which affects the parentage and the resistant system . Astronauts also have a high-pitched incidence of eye problems , and this could be related to thecosmic ray ocular phenomenon . spaceman see light heartbeat due to energetic cosmic rays going through their eyeballs .
Cancer and the accelerated onset of Alzheimer ’s disease are other possible consequence of prolonged time in space .
Weightlessness
The ISS is in constant freefall , which generates the apparent lack of gravity . This create a unequalled environment to push scientific limits , but at the same prison term , this has knockout health consequences on the astronaut .
The body react to weightlessness by redirecting elsewhere the resourcefulness it uses to maintain bone and muscles healthily . Astronauts drop off about 1 to 2 pct of bone tissue each month . This is like to people who suffer from osteoporosis . A year in outer space could melt off the bone tissue in extremity and hip by over 20 percent .
Weightlessness also affects muscles . Without exercise , astronaut can lose20 percentof their muscular tissue mass in 5 to 11 days . For this rationality , spaceman on the ISS spend 2.5 hours a day practise . Even with the constant exercise , astronauts can still lose 40 percent of their muscle after 5 calendar month in space .
red of bone and muscle tissue is not permanent , but it takes years for an cosmonaut to render to pre - mission state . Diet and postscript to recreate this physical process are also use by medical professional to regale osteoporosis .
On a potential plus side , astronauts become taller in space .
Astronaut Andre Kuipers runs on a treadmill on the ISS . NASA
Other Effects
There are other physiological and psychological effect . Many astronauts cover a change in their sentiency of taste , something that occasionally stay when they hark back to Earth . Astronauts also describe back and abdominal pain . These muscles are freely stretched when in space , and can have problems readjusting to somberness .
spaceman lose about 22 percent of their descent intensity . With less blood to pump , the heart begins to atrophy , which could run to bad tissue oxygenation , and they often experiencefaintness and lightheadedness .
foot also go through apeculiar translation . The top of metrical foot becomes raw and painfully sore , while the bottom after a few months molt wholly and lose all the hard callosity . So , it ’s not all bad .
Mission to Mars
The journey to Mars is not live to be an easy one . Away from the protective buckler of Earth ’s magnetic field the radiotherapy grade are much higher . Astronauts are expected to be expose to 100 times more radiation in an 180 - day journey to Mars than one year on Earth .
Scott Kelly ’s rehabilitation is being study in detail because it is going to be similar to what spaceman put down on Mars will experience . A mission to the Red Planet will require careful preparation to account for all the potential wellness risks the succeeding astronauts will encounter .
There are also psychological effects to turn over . leave behind Earth behind in a minuscule space capsule with six other mass for up to 3 years is not become to be gentle for anyone .
