A: The main threats to human health and performance associated with space flight are radiation, altered gravity fields, hostile and closed environments, distance from Earth, and isolation and confinement. These five hazards stem the health and performance risks studied by NASA's Human Research Program. Cosmic radiation, fragments of atoms charged with energy from the Sun, and supernovae outside our galaxy can cause anxiety, depression and decision-making problems in astronauts. One of the first changes in the body is the movement of fluids.
On Earth, our muscles work to pump fluids through the body against gravity, and gravity helps to return them. Even though astronauts enter a lightweight environment, their muscles continue to work as if they were on Earth. This causes fluids to be pumped up and concentrated in the upper body. The change in fluids causes a swelling of the head that is often seen in astronauts.
It can also cause an increase in pressure in the back of the eye, which can change its shape and can change vision. Without gravity, there is a loss of muscle mass and bone density. To counter these changes, astronauts exercise for two hours a day. The station's exercise devices include a treadmill and an ARES for resistance exercises.
However, these machines take up quite a bit of space, so NASA is working on a miniaturized version for Orion, where space is a scarce commodity. The vestibular or balance system is also affected by the absence of gravity. Within this system, in our inner ear, there are small crystals that give us information about our orientation. Without gravity, there is no signal to tell the body in which direction it is “up”.
The mismatch between information from astronauts' eyesight and information from the vestibular system often causes a feeling of dizziness or space sickness. Many people who go to space suffer from space sickness (see motion sickness), which can cause vomiting, nausea and stomach discomfort, among other symptoms. The condition is believed to arise from a contradiction experienced in the brain between external information that comes from the eyes and the internal information that comes from the balance organs of the inner ear, which are normally continuously stimulated by gravity. Space sickness usually disappears in two or three days as the brain adapts to the space environment, although symptoms may reappear temporarily when the space traveler returns to Earth's gravity.
Candidates undergo rigorous training before being chosen for an initial space flight and are then prepared in detail for each assigned mission. If astronauts start to feel that way when both Earth and their destination are nothing more than small dots in space, things will feel even bleaker, Stuster says. Finding a way to limit the dangers of space and learning from past mistakes will ensure the safest flight to Mars and beyond. Although changes in muscle, bone and blood production do not pose problems for astronauts in space, they do when they return to Earth.
With the development of long-duration space stations, such as the Mir and the ISS, the distinction between pilot and non-pilot astronauts and cosmonauts has become less clear, because all members of the crew of a space station carry out operations and experiments on the station. Space engineers must design adequate radiation shielding for manned interplanetary spacecraft and will need accurate predictions of radiation damage to the body to ensure that risks remain within acceptable limits. They also argue that astronauts are excellent role models for young people and act as indirect representatives of the many who would like to fly themselves in space. For example, under normal gravity conditions, a person with reduced bone mass is at greater risk of fracturing a bone during normal strenuous activity.
And if fumigatus lives well in space, the researchers write, so could many other, more lethal pathogens. Providing the systems to help people while in orbit adds significant additional costs to a space mission, and ensuring that launch, flight and re-entry are as safely as possible also requires highly reliable and, therefore, expensive equipment, including both spacecraft and launchers. But how intense are the dangers of actually traveling through space? Here are five of the most dangerous threats astronauts will face when they travel to Mars and beyond. On a years-long journey to deep space with no pit stops, an argument could mean life or death for crew members.
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