Space exploration is an exciting and potentially rewarding endeavor, but it also comes with a number of risks. From radiation to altered gravity fields, hostile and closed environments, distance from Earth, and isolation and confinement, there are a number of hazards that astronauts must face when venturing into the unknown. In this article, we'll explore the five main threats to human health and performance associated with space flight, and what measures are being taken to ensure the safety of astronauts. The first risk astronauts face is radiation. 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.
To protect against this, NASA's Human Research Program is studying the health and performance risks associated with space flight. The second risk is altered gravity fields. On Earth, our muscles work to pump fluids through the body against gravity, and gravity helps to return them. In space, however, astronauts enter a lightweight environment where their muscles continue to work as if they were on Earth. This causes fluids to be pumped up and concentrated in the upper body, resulting in 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. The third risk is a hostile and closed environment. Without gravity, there is a loss of muscle mass and bone density. To counter these changes, astronauts exercise for two hours a day using devices such as treadmills and 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 fourth risk is distance from Earth.
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. The fifth risk is isolation and confinement.
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. 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 exploration and learning from past mistakes will ensure the safest flight to Mars and beyond.
With the development of long-duration space stations such as Mir and ISS, the distinction between pilot and non-pilot astronauts has become less clear as all members of the crew carry out operations and experiments on board. Space engineers must design adequate radiation shielding for manned interplanetary spacecraft and will need accurate predictions of radiation damage to ensure that risks remain within acceptable limits. Astronauts are also excellent role models for young people as they act as indirect representatives of those who would like to fly themselves in space. When returning to Earth's gravity after spending time in space, changes in muscle, bone and blood production can pose problems for astronauts. If fumigatus lives well in space, researchers suggest that many other more lethal pathogens could also survive in this environment. Providing systems to help people while in orbit adds significant additional costs to a space mission while ensuring launch, flight and re-entry are as safely as possible requires highly reliable equipment including both spacecrafts and launchers. Space exploration comes with its own set of risks but with proper preparation and training these risks can be minimized.
On a years-long journey to deep space with no pit stops, an argument could mean life or death for crew members so it's important that astronauts are well-prepared for any situation they may encounter.