Hi Christy, Long term exposure of human physiology to low gravity environments will put Martian colonists at significant risk. Our bodies evolved on a planet exerting a g-force of one. We are conditioned to thrive under an envelope of air and a magnetic field that shields us from the worst the Sun and Universe can throw our way. And although we theoretically think that we will be able to grow crops on Mars, it is an undertaking that has yet to happen on the planet itself. All we have is a few Martian meteorites and sample analysis which we can simulate.

And finally, the amount of money deemed to meet the objectives of the Mars One Project is a trifle compared to what Russia, China and the U.S. spend on less ambitious space projects. Now I know that private enterprise finds efficiencies where public bureaucracies fail, but we are talking about sending 4 people on a one-way trip that will take 6 to 7 months and then asking them to acclimate to a closed-system environment on a remote planet with basic infrastructure and little in the way of backup. I understand the dream of going to Mars. I understand the attraction this holds for so many. But a saner project would be to first establish permanent residency much closer to Earth – at a Lagrange point for example, or eventually a lunar base. Leaping to Mars is more than believing in the possible. It is under the current scenario a leap to death.

There are a few corrections I might suggest.
From point 1. Researchers have already determined that plants will grow in martian soil (much better then lunar sand) http://www.ibtimes.co.uk/martian-soil-suitable-growing-plants-researchers-find-1432658 And while pressure remains a concern, scientists do not believe it to be unsolvable http://science1.nasa.gov/science-news/science-at-nasa/2004/25feb_greenhouses/

From Point 4 – Because of improved exercise routines and machines (as well as better nutrition) this problem is becoming less important over time. I can’t find the link but one female astronaut came back with stronger hips bones then when she left. http://www.nasa.gov/mission_pages/station/research/news/bone_study_news.html
Furthermore, once on Mars the crew will have less to adapt to because of the lower gravity. This is also make the transition easier.

There is no doubt that the Martian environment is about the most unfriendly place that humans will ever attempt to inhabit. But the Mars One project, and those who dream of Mars as the next outpost for humanity are convinced that it can be done. I remain a skeptic for the same reasons you do.

Seems unlikely that humanity could ever colonize Mars prior to a time when AI robots could colonize Mars. It’s hard to envision how that could happen before robots “colonize” the asteroid belt and use the materials there to build space habitats for humans. Let the manned Mars mission proponents establish a permanent and self-sufficient Sahara desert colony on Earth, which obviously would cost pennies versus the millions required for a manned Mars mission, and then get back to us with their man-on-Mars ambitions. So it’s all pipe dreams writ large.