We already know that interplanetary travel will be extremely expensive and may take months or years to achieve one-way trips to Mars and other planets. In addition to the long travel times and expense, there is also the concern about the effects of exposure to deep-space radiation. Based on theories, laboratory experiments and actual deep-space measurements, scientists have confirmed that this may be a serious deterrent to human, deep-space travel.

A primary concern is the health threat from galactic cosmic rays and solar energetic particles. Galactic cosmic rays are made up of high energy protons, helium and other high energy nuclei. Solar energetic particles are primarily protons that are accelerated by the Sun to high energy levels.

Astronauts in low Earth orbit, such as International Space Station occupants are not exposed to these rays because they are shielded by the close proximity to Earth, just as those living on the surface of the planet.

However, travel to destinations beyond the Van Allen belts may result in increasingly damaging radiation. For example, the Apollo lunar astronauts were exposed to some of this radiation, but for short times.

Nevertheless, they could detect cosmic rays. Moon-bound crews did report seeing flashes of light when they closed their eyes. Scientists explain this as galactic cosmic rays speeding through their retinas. Travelers to Mars and other interplanetary destinations may be exposed to dangerous radiation for very long periods of time.

Although most people are not aware of it, life on the Earth's surface is protected from galactic cosmic rays by our atmosphere, our magnetic field and the interplanetary magnetic field. As a result, the effects of radiation on earth-bound humans is negligible.

During the 2011-2012 timeframe, NASA's Radiation Assessment Detector (RAD) onboard the Mars Science Laboratory did detect radiation sufficient to be hazardous to crews travelling to the Red Planet.

In a recent NASA-funded study of radiation effects on long-term space travel, mice were exposed to prolonged bombardment by charged particles, simulating deep-space conditions. Scientists concluded that cosmic ray exposure during interplanetary voyages could cause subtle brain damage to astronauts, leaving them confused, forgetful and slow to react to unexpected situations.

Human spaceflight and interplanetary travel present exciting new opportunities for scientists, engineers and entrepreneurs. To better understand the challenges Launchspace has created a critically-important course for those involved and interested in the science and technology associated with men and women traveling beyond Earth's atmosphere. Check it out here.