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| Mars composite image - (c) Jet Propulsion Laboratory |
Mars, the planet which has conjured many a science fiction movie and not a few novels. Seemingly close, the nearest planetary neighbour to Earth is nonetheless very distant to this planet and travel over such a large distance poses both technical challenges and extreme health risks for humans attempting the voyage.
In terms of orbit around the Sun, Mars is always 48.3 million or more kilometres away from the Earth which equates to around 140 times further than the moon. In terms of transit time, this distance would mean around 210 days to travel from the Earth to Mars depending on the best available launch window and capability in velocity based on the existing propulsion systems or those in the design stages. Once at Mars, a mission team would need to wait around 496 or so days before being able to commence a return flight to Earth.
What sort of space vehicle would be able to both propel the pay load safely to Mars and be able to sustain a flight crew during transit to the planet ? It would need to have sufficient speed to cover the distance with a size and scale to include the necessary life support functions including air and water to sustain the crew. Existing fuel burning engines would not suffice due to the amount of fuel which would need to be carried and a solar powered vehicle would be slow moving indeed. Mounting a nuclear engine on a manned space vehicle carries its own multi-level high risks.
The technology to reach Mars is not insurmountable however the physical health ramifications for astronauts may yet pose an almost impassable barrier. Existing data from Moon missions, Skylab and the International Space Station have demonstrated the punishing effect of long term exposure to weightlessness on the human body - bones waste away at a rate of one percent of bone mass per month; fluid can collect behind eyeballs and cause blurred vision; radiation from solar flares and cosmic rays (which are high energy particles travelling at close to light speed) pose a direct threat to DNA and human brain cells. These are only the known factors as already identified with potentially many more.
In terms of orbit around the Sun, Mars is always 48.3 million or more kilometres away from the Earth which equates to around 140 times further than the moon. In terms of transit time, this distance would mean around 210 days to travel from the Earth to Mars depending on the best available launch window and capability in velocity based on the existing propulsion systems or those in the design stages. Once at Mars, a mission team would need to wait around 496 or so days before being able to commence a return flight to Earth.
What sort of space vehicle would be able to both propel the pay load safely to Mars and be able to sustain a flight crew during transit to the planet ? It would need to have sufficient speed to cover the distance with a size and scale to include the necessary life support functions including air and water to sustain the crew. Existing fuel burning engines would not suffice due to the amount of fuel which would need to be carried and a solar powered vehicle would be slow moving indeed. Mounting a nuclear engine on a manned space vehicle carries its own multi-level high risks.
The technology to reach Mars is not insurmountable however the physical health ramifications for astronauts may yet pose an almost impassable barrier. Existing data from Moon missions, Skylab and the International Space Station have demonstrated the punishing effect of long term exposure to weightlessness on the human body - bones waste away at a rate of one percent of bone mass per month; fluid can collect behind eyeballs and cause blurred vision; radiation from solar flares and cosmic rays (which are high energy particles travelling at close to light speed) pose a direct threat to DNA and human brain cells. These are only the known factors as already identified with potentially many more.
So Mars travel remains a dream at the moment. NASA and private companies such as SpaceX have the intention to reach the red planet but for the now the only visitors will remain remote mobile robotic devices scanning the landscape for, as yet, undetected discoveries.
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| Strata at the base of Mount Sharp, Mars: (c) NASA Mars curiosity rover |
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