A human mission to visit and land on the planet Mars has long been a subject for science fiction writers and a dream of space exploration advocates. Though various mission proposals have been put forth by multiple space agencies for such a mission, the logistical and financial obstacles are considerable, and many critics contend that such a mission would be a risky sub-optimal use of government resources.Regardless, preliminary work for such a mission is being undertaken by NASA and the European Space Agency, with each projecting a possible attempt in the late 2020s or the 2030s. In 2006, President George Bush laid out a vision for both returning to the Moon and pushing on to Mars. Since then, debate surrounding whether to go to Mars has been very prominent. The main questions surrounding a mission to Mars include the following: Would a mission to Mars be inspirational for humankind? Should this be a major consideration? Is there scientific value in sending a manned mission to Mars? Are humans necessary for certain mission-objectives, or are robots adequate and possibly superior? Is a manned mission to Mars feasible? Are the risks tolerable? Is overcoming the risks too complicated and possibly too expensive? Are there any possible economic benefits from a mission to Mars? How much will it cost? Will the costs draw significant amounts of funding away from social services and possibly require raising taxes? Will new opportunities be created? Will it inspire a new generation of engineers? Overall, does the balance of pros and cons justify sending a manned mission to Mars?
See Wikipedia’s article on the topic for more background: Manned mission to Mars
“By refocusing our space program on Mars for America’s future, we can restore the sense of wonder and adventure in space exploration that we knew in the summer of 1969.”
“The question of taking on Mars as an interplanetary goal is not simply of aerospace accomplishment, but one of reaffirming the pioneering character of our society.”
“Our children are raised in a world without heroes. They are led to believe that heroism consists of throwing a football the furthest, getting the most hang time during a slam dunk, or selling the most movie tickets with your looks and your boyish charm. […] Going to Mars is not a luxury we can’t afford. It’s a necessity we can’t afford to be without. We need this. […] We need this, or some kind of challenge like it, to bring us together to all feel a part of something and to have heroes again.”
“We ought to gather the international community and go to Mars. I know it isn’t how others feel because it is much cheaper to go back to the Moon but I would rather we went to Mars. If we did it with all those other countries it would have a tremendously unifying effect on the Earth. It would be an inspiration for all people on Earth.”
“Two centuries ago, Meriwether Lewis and William Clark left St. Louis to explore the new lands acquired in the Louisiana Purchase,” George W. Bush said, announcing his desire for a program to send men and women to Mars. “They made that journey in the spirit of discovery … America has ventured forth into space for the same reasons.[…] Yet there are vital differences between Lewis and Clark’s expedition and a Mars mission. First, Lewis and Clark were headed to a place amenable to life; hundreds of thousands of people were already living there. Second, Lewis and Clark were certain to discover places and things of immediate value to the new nation.”
“The thought of travel to Mars is exhilarating. Surely men and women will someday walk upon that planet, and surely they will make wondrous discoveries about geology and the history of the solar system, perhaps even about the very origin of life. Many times I have stared up at Mars in the evening sky–in the mountains, away from cities, you can almost see the red tint–and wondered what is there, or was there. […] But the fact that a destination is tantalizing does not mean the journey makes sense, even considering the human calling to explore. And Mars as a destination for people makes absolutely no sense with current technology.”
A manned mission to Mars would provide us with a greater understanding of the human body and how it functions after long periods in space, possibly bringing medical advancements.
“We learned in the 1960s that Mars’s surface has features that, as far as we can tell, can only have been made in the presence of water: standing water, running water, deluging water. There are features that look like they’re floodplains. There are riverbeds that are straight and riverbeds that meander. Combine all of this, and you consider how important water is to life on Earth, you can’t help but speculate that Mars was once a really wet place, possibly even harboring life at one point. So much of what drives cosmic exploration involves the quest to learn whether or not we’re alone in the Universe—as an intelligent species, or as life at all. Mars being so close compared with the rest of the cosmos—it’s a slam dunk as a place you want to go visit.”
“Another reason why humans may have to be on site to conduct a thorough search for life stems from the fact that if any such life exists it is probably deep underground. Upcoming probes will be equipped with robotic assemblies that can bore several centimeters into rocks or dig a few meters down into the soil. But barring any discoveries at those shallow depths, researchers will have to bring up samples from hundreds of meters below the surface, maybe even one or two kilometers down, before they can declare Mars dead or alive. Drilling for samples at such depths ‘most likely will require humans,’ says Charles Elachi, director of the Space and Earth Sciences Program at the Jet Propulsion Laboratory in Pasadena, Calif.”
“The first manned landing on Mars would serve as an invitation to adventure for children around the world. There will be some 100 million kids in the U.S. schools over the next 10 years. If a Mars program were to inspire just an additional 1 percent of them to pursue scientific educations, the net result would be one million more scientists, engineers, inventors, medical researchers and doctors.”
Because a robotic mission to Mars is so much cheaper than a manned mission, many more unmanned missions can be sent. The Mars rover missions cost about $250 million a pop. An optimistic estimate puts the cost of sending humans to Mars at $160 billion. Others think it could cost as much as a trillion dollars. That is 640 Mars rover missions. This means that a manned mission will probably obtain almost 1/600th of the scientific data, and possibly 1/600th of the scientific knowledge and progress. A manned mission, therefore, is decidedly unscientific in this regard.
“It is interesting to note that when President Bush unveiled his proposal, he listed these recent major achievements of space exploration: pictures of the rings of Saturn and the outer planets, evidence of water on Mars and the moons of Jupiter, discovery of more than 100 planets outside our solar system and study of the soil of Mars. All these accomplishments came from automated probes or automated space telescopes. Bush’s proposal, which calls for ‘reprogramming’ some of NASA’s present budget into the Mars effort, might actually lead to a reduction in such unmanned science–the one aspect of space exploration that’s working really well.”
“Robotic exploration delivers countless advantages. It is true that there will always be situations where a live human being will be able to adapt and think through situations which would leave a machine crippled in the dust. But have we done so badly with the robots currently in service? Two rovers on Mars are still trundling along, dragging disabled wheels and running on low power due to dust covered solar panels, but performing their mission years beyond initial projections. Also, unmanned missions are free of the burden of delivering air, food, water, and all of the other requirements for keeping humans alive. They weigh less, cost less, and can take all the time they need to arrive at their destination.”
“There are many of people who, if told that they could be part of an expedition to Mars only if they abandoned all hope of returning to Earth, would jump at the chance. Thousands more would sign up for a trip where their chances of returning were only 50/50. Looking back over time, people have always been willing to risk their lives for things they care about, for great missions of exploration. More importantly, why should people who will be staying safely here on Earth deny the people who wish to take that chance the opportunity, just because the explorers might die?”
Radiation only becomes dangerous when absorbed in large quantities, over short periods of time. According to the National Academy of Sciences National Research Council, a dose of 100 rem causes a 1.81% increase in the likelihood of cancer in the next 30 years of a person’s life. Astronauts inside a spaceship during any of the last 3 large recorded solar flares would have experienced doses of 38 rem; inside of the storm shelter – 8 rem. On the surface of Mars, which offers much radiation protection due to its atmosphere, the unshielded dose would have been 10 rem, the shielded dose 3 rem. In total, radiation doses of 52.0 and 58.4 rem taken on the missions, are well below dangerous thresholds — even were they to come all at once. 
“When the Mars Polar Lander entered the Martian atmosphere in 1999, it immediately fell silent and was never heard from again. It is now believed that it crashed into the wall of a canyon, smashing on the rocks far below. It was a terrible loss in terms of technology and discovery, disappointing many, but imagine our reaction if that had been a landing craft with five astronauts on board. Some risks are still best left to our machine surrogates.”
“It’s not that American heroes are in short supply. The waiting list of brave, daring professionals hoping to enter the space program is massive, and many stand ready to risk their lives to advance the cause of science and push mankind past any and all boundaries. But is this really the way we wish to spend those lives?”
“NASA needs to come up with solutions for effectively protecting the astronauts from the high levels of cosmic radiation they will be exposed to in deep space and on the surface of Mars. They will also need medical equipment for the diagnosis and treatment of illnesses or injuries.”