"Radiation kills astronauts "

Astronauts face many problems. They sacrifice their lives for us and for science. Let's take a ride into space, away from Earth, from the family, and from the atom of oxygen. It's a long, exciting and exciting journey...

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radiation:

What is Radiation?

 Outside the protective cocoon of the Earth’s atmosphere is a universe full of radiation – it is all around us.

Radiation is a form of energy that is emitted in the form of rays, electromagnetic waves, and/or particles. In some cases, radiation can be seen (visible light) or felt (infrared radiation), while other forms—like x-rays and gamma rays—are not visible and can only be observed with special equipment. Although radiation can have negative effects both on biological and mechanical systems, it can also be carefully used to learn more about each of those systems.

Where Does Radiation Come From? 

Radiation can be created by humans (microwaves, cell phones, radios, light bulbs, diagnostic medical applications such as x-rays) or naturally occurring (the Sun, radioactive elements in the Earth’s crust, radiation trapped in the Earth’s magnetic field, stars, and other astrophysical objects like quasars or galactic centers). Earth’s biggest source of radiation is the Sun. The Sun emits all wavelengths in the electromagnetic spectrum (EM). The majority is in the form of visible, infrared, and ultraviolet radiation (UV). Occasionally, giant explosions, called solar flares, occur on the surface of the Sun and release massive amounts of energy out into space in the form of x-rays, gamma rays, and streams of protons and electrons. This is called a solar particle event (SPE). These solar flares can have serious consequences to astronauts and their equipment, even at locations that are far from the Sun. Non-Ionizing versus Ionizing Radiation Radiation can be either non-ionizing (low energy) or ionizing (high energy). Ionizing radiation consists of particles that have enough energy to completely removing an electron from its orbit, thus creating a more positively charged atom. Less energetic, non-ionizing radiation does not have enough energy to remove electrons from the material it crosses.

What is Space Radiation? 

Space radiation is different from the kinds of radiation we experience here on Earth. Space radiation is comprised of atoms in which electrons have been stripped away as the atom accelerated in interstellar space to speeds approaching the speed of light – eventually, only the nucleus of the atom remains. Space radiation is made up of three kinds of radiation: particles trapped in the Earth’s magnetic field; particles shot into space during solar flares (solar particle events); and galactic cosmic rays, which are high-energy protons and heavy ions from outside our solar system. All of these kinds of space radiation represent ionizing radiation.

Why is Ionizing Radiation More Dangerous than Non-Ionizing Radiation? 

While non-ionizing radiation is damaging, it can easily be shielded out of an environment as is done for UV radiation. Ionizing radiation, however, is much more difficult to avoid. Ionizing radiation has the ability to move through substances and alter them as it passes through. When this happens, it ionizes the atoms (knocks electrons out of them) in the surrounding material with which it interacts. Ionizing radiation is like an atomic-scale cannonball that blasts through material, leaving significant damage behind. More damage can also be created by secondary particles that are propelled into motion by the primary radiation particle. The particles associated with ionizing radiation in space are categorized into three main groups relating to the source of the radiation: galactic cosmic rays, solar flare particles, and radiation belt particles (Van Allen Belts) trapped in space around the Earth. 

How much Space Radiation are Astronauts Exposed to?

 Beyond Low Earth Orbit, space radiation may place astronauts at significant risk for radiation sickness, and increased lifetime risk for cancer, central nervous system effects, and degenerative diseases. Research studies of exposure in various doses and strengths of radiation provide strong evidence that cancer and degenerative diseases are to be expected from exposures to galactic cosmic rays (GCR) or solar particle events (SPE). Milli-Sievert (mSv) is a form of measurement used for radiation. Astronauts are exposed to ionizing radiation with effective doses in the range from 50 to 2,000 mSv. 1 mSv of ionizing radiation is equivalent to about three chest x-rays. So that’s like if you were to have 150 to 6,000 chest x-rays.

What Is Galactic Cosmic Radiation?

 Galactic Cosmic Radiation (GCR) is a dominant source of radiation that must be dealt with aboard current spacecraft and future space missions within our solar system. GCR comes from outside the solar system but primarily from within our Milky Way galaxy. GCR is composed of the nuclei of atoms that have had their surrounding electrons stripped away and are traveling at nearly the speed of light. Another way to think of GCR would be to imagine the nucleus of any element in the periodic table from hydrogen to uranium. Now imagine that same nucleus moving at an incredibly high speed. The highspeed nucleus you are imagining is GCR. These particles were probably accelerated within the last few million years by magnetic fields of supernova remnants. In summary, GCR are heavy, high-energy ions of elements that have had all their electrons stripped away as they journeyed through the galaxy at nearly the speed of light. They can cause atoms they pass through to ionize. They can pass practically unimpeded through a typical spacecraft or the skin of an astronaut

The effects of radiation on the human body:

Space radiation is one of the main health hazards of spaceflight. It is dangerous because it has sufficient energy to change or break DNA molecules, which can damage or kill a cell. This can lead to health problems ranging from acute effects to long term effects.

Acute effects such as changes to the blood, diarrhea, nausea, and vomiting are mild and recoverable. Other effects of acute radiation exposure are much more severe such as central nervous system damage or even death. Acute effects are not expected to result from exposure to space radiation, except if an astronaut is exposed to a large solar particle event, such as a solar flare, which produces a high dose of radiation.

The major concern about space radiation is the long term effects on astronauts. Long term effects can include cataracts, increased chance of cancer, and sterility. Some health effects can skip a generation and appear in the descendants of the exposed individual, being passed on by mutated genes.

The types of health problems that occur are determined by the extent of exposure to radiation, an astronaut's vulnerability to radiation and other variables. Exposure to radiation depends on:

• Altitude of the spacecraft
• Amount of shielding from the spacecraft or spacesuit,
• Length of mission,
• Duration and intensity of exposure,
• Type of radiation.

Vulnerability to radiation includes individual sensitivity to radiation and differences in age, sex, or health status. In addition, variables such as weightlessness or body temperature can weaken the human immune system and affect how body tissues and organs respond to radiation.