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Blog written by Joan Vernikos PhD, Thirdage llc, Culpeper VA, USA  While teaching Pharmacology at Ohio State University (OSU), I was lured to NASA Ames Research Center in 1964 by Dr.Eric Ogden, the Chair in Physiology at OSU and a cardiovascular physiologist, to join him in a small unit of five research scientists. My background had been in brain/stress regulation; there was also a microbiologist, an exercise physiologist, a metabolism and a biological rhythm scientist. Very little was known about what happens to humans in space; our observations from one flight to the next slowly enabled us to form a picture of what might be happening, but progress was gradual. We had to find a way to at least simulate the effects of space flight on the ground and facilitate research that would complement and help us understand what the consequences of living in the microgravity of space might be.  Image from article by Hargens & Vico Published 15/04/2016 DOI:10.1152/japplphysiol.00935.2015 Eventually, the optimal model adopted by the space science research community as a means for studying the physiological changes occurring in weightlessness during spaceflight was 6˚ Head Down Bed Rest (HDBR) or variations of this. In essence, by lying down continuously, the maximum influence of the force of gravity pulling down on us, Gz (head-to-toe), is minimised to Gx (across the chest). It was from such studies in healthy volunteers that I first noticed the similarity in changes seen in astronauts in space to those of people ageing on Earth. Muscle and bone wasting, reduced blood volume, a type of anemia, fluid and electrolyte shifts, cardiovascular deficits, and reduced aerobic capacity alterations in space all resulted on return to Earth in the astronauts experiencing fainting, and disturbed balance and coordination. These changes are also known to be the underlying causes of falls in the elderly. However, this conclusion was met with disbelief, including my own, since healthy young astronauts and HDBR volunteers recovered soon after returning to Earth or on becoming ambulatory. As knowledge accumulated and the duration of space missions grew longer, it has become clear that both the physiological response to spending time in space, as well as the ageing process on Earth, are gravity-dependent conditions.
Manned exploration of Mars is really only a matter of time, and some even say it is a necessity that we step foot on Martian soil. Stephen Hawking declared at a lecture in 2008 "If the human race is to continue for another million years, we will have to boldly go where no one has gone before", while SpaceX entrepreneur Elon Musk confirmed his belief that "Humans need to be a multiplanet species" in an interview with website Slate in 2015. Currently there are two operational and mobile US Mars rovers exploring the surface of the planet, Opportunity landed successfully in 2004 and Curiosity in 2012, so there is already much we know about the surface and landscape of the Red Planet. What awaits any visitors to Mars is a very hostile and harsh environment; its atmosphere is about 100 times thinner than Earth's and is 95% carbon dioxide; temperatures can range from -125°C near the poles in winter to +20°C at midday near the equator; and the surface is covered in a layer of dust containing very fine-grained silicate minerals that tend to stick to surfaces and could be hazardous if breathed in. So the question is how to prepare astronauts for what they are likely to confront on an inhospitable planet that lies at least 55 million kilometres away? "An ounce of practice is worth more than tons of preaching." There is undoubtedly no landscape on Earth that can exactly match the harshness of the Mars conditions, however, we can get close, such as on Mauna Loa volcano, Hawaii where Hi-SEAS analogue missions take place, the Atacama desert in Peru/Chile with its Mars-like arid soils where only the most limited of bacteria can survive, and the Dhofar desert in Oman, where in February 2018 the AMADEE-18 Mars analogue will take place. The use of field research in an environment that mimics Mars conditions in some form is an excellent way of gaining experience, practicing for the 'real thing', but more importantly, understanding the advantages and limitations presented by remote science operations where access to and communications with a central control are subject to difficulties and delays.
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