How Effectively Can We Protect Astronauts From Cosmic Radiations On Mars?
On a day to day basis, we hardly care to realize that how the earth protects us from outer objects and space radiations. With the advent of space exploration age and our intense fascination towards astronomy, long space journeys appear very much on the horizon.
The deep space travel, however, comes with many expected as well as unknown risks. The cosmic radiations coming out of the sun and from distant galaxies can pose a great risk for space travel. The scientists have spent a great deal of their time and efforts to understand the effects of these radiations all this while.
For quite some time now, astronauts have been traveling from the earth and the International Space Station (ISS). But they are also gearing up for longer journeys much deeper into our solar system in coming years. This will increase their risk of getting exposed to these harmful space radiations. The immediate danger being posed to the astronauts after leaving the earth’s influence is in the form of solar flares coming directly from the sun’s surface. These solar flares are a result of coronal mass ejections that are an accelerated wave of extremely high energized particles, which can damage the circuitry of satellites and cause cancers to humans. In addition to these particles, the astronauts are constantly bombarded by the cosmic radiations coming from the deep space that are believed to originate from supernovas.
A Trip to the Mars
For a long time, Mars has been an object of great curiosity for the scientists and astronomers equally. We have so far sent dozens of probes on its surface in order to study its atmosphere and landscape. In many ways Mars is somewhat similar to the earth – it has a 24-hour day, it has polar ice caps, it has tilted axis with its orbit, and it has the kind of landscape that forms by flowing water.
Elon Musk – CEO of SpaceX, a widely known private space agency – has revealed his plans of carrying out multi-planetary space journeys by sending crews to Mars and beyond. However, the Mars mission will not be a cake walk. The recently released Hollywood film “The Martian” also underlines some potential risks humans can face on Mars in accordance with the risks evaluated by NASA – gravity fields, isolation, hostile environment, space radiation, and distance from the earth.
Protecting Astronauts from Space Radiation
According to the NASA’s 2001 Mars Odyssey spacecraft, the astronauts on the Martian surface will be prone to receive 2.5 times higher radiation levels as compared to the ISS – 22 millirads per day, which means 8000 millirads per year. This radiation level if kept unchecked will render them at an increased risk of cancer, potential damage to the central nervous system, degenerative tissue diseases and radiation sickness. There are many ways by which radiations penetrate the human body that will ultimately pave way for the above mentioned risks. NASA is coming up with unique ways to monitor and measure how radiation affects humans while living in space, and to identify their biological countermeasures. It is even developing methods to optimize shielding in order to protect the astronauts on a journey to Mars.
The scientists of NASA and other premier space agencies around the world are studying sun’s modulation in order to make better decisions for the future Mars missions. This field of study and research is known as Heliophysics, which helps us better understand how and when solar eruptions occur as well as their overall impact on space radiation environment. The second source of radiations, better known as galactic cosmic rays (GCRs) are more difficult to shield. They are also highly energized particles and accelerated to near the speed of light and reach to a dangerous level. These constitute of even heavier elements that can knock out atoms from the materials such as space suits of astronauts and walls of spacecraft.
When it comes to the protection of the astronauts, today’s technology depends on passive as well as active shielding. The passive protection involves the creation of a barrier between astronauts and the incoming radiation. The active shielding, on the other hand, involves the use of electric and magnetic fields to divert harmful radiations. As far as the lengthier missions such as the one to the Mars are concerned, passive shielding will likely not work for extended time period. This type of protection is too expensive a proposition as well. According to the European Union’s Space Radiation Superconducting Shield (SR2S), adding an extra weight of 2.2 pounds to a spacecraft results in a $15,000 rise to the overall cost of the mission. In this regard, a safer and economically more feasible technology is underway in the form of magnetic cables.
In another similar attempt NASA is developing a material that can act as an effective shield as well as the primary structure of a spacecraft. This material is known as Hydrogenated boron nitrite nanotubes or Hydrogenated BNNTs, which is made up of carbon, boron, and nitrogen with hydrogen in the empty spaces between the tubes. This material provides a strong physical structure along with the capability of excellently absorbing the secondary neutrons.
In order to create an effective force field for the protection of astronauts, scientists are considering Magnesium Diboride (MgB2) as a powerful compound. In this direction, an Italian Company Columbus Superconductors has used MgB2 for medical applications as well as magnetic levitation. The theory suggests these cables can create a superconducting magnetic force field that can go a long way to protect astronauts on their journey to Mars.
With the arrival of aggressive space age, the space journey will also begin sooner or later. Astronauts are the ones who will have to bear the brunt of radiations when they travel into the deep space. Even if we assume that the mission to Mars will not necessarily be fatal, but there are certain health risks for the astronauts that need to be addressed. Different space agencies along with scientists are coming up with different methods to protect astronauts from harmful radiations. These methods include induced barriers and artificial force fields and superconducting magnetic shield.