Man cannot help but look at the stars and think, "I wonder what is out there". If technology has showed us anything that a little ingenuity, elbow grease, and a dash of loveable science can get us to even the most distant of goals. It worked to get a man into space and even to the moon, so why not a space flight to Mars. After the moon, Mars was the next goal. We cannot get much closer to the sun without disaster, so the natural choice was to go the opposite direction.
However, with technology at its current state Mars space travel is just another pipe dream. The moon was a pipe dream once too, though.
So why can we not go to Mars?
All of our space activates have been achieved by the propulsion method of rocketry. However, if you ask any scientist, rocketry is a grossly resource and energy inefficient method there is. You know, aside form billions of rubber bands attached to a giant slingshot.
Before even leaving Earth's atmosphere, a space shuttle must travel at approximately 11 km per second--which is about 25,000 miles per hour. To reach those speeds, a shuttle must use around 2,200,000 pounds of fuel split between the two boosters. It is essentially like placing a giant bomb under a tube and controlling the explosion. You can see how this is not a great way to get into space, as once you enter space, you have lost the boosters and still must be able to have fuel to propel the space craft to Mars and back.
Sadly, this isn't science fiction and science fiction does not want to share its secrets on how to propel spacecrafts without rocketry. Rocketry is all we have for the moment, and there is not a way that rocketry can get us to Mars and back.
If you put four best friends in a room with little to do and left them there for about a week, you would probably open up the room to find a blood bath. People were not meant to spend time with other people in a confined space for long periods of time. No matter how friendly you think you are, you need a little time to yourself.
Space dementia is essentially cabin fever in space. Mars is a pretty long distance. At it's closest period, it is about 8 months of travel away. No matter how excited those astronauts are about making history, about a month in they will be ready to strangle one another. Not to mention the 8 month-ish ride back.
The longest an astronaut has been in space to date is 437.7 days. This was done by Valeri Polyakov in 1994 to 1995. He was along for about 258 days of that stint. How did he fight the space dementia? He was always in contact with Russian headquarters and he filled his endless void of free time by conducting experiments. Though when tested after his stay, Polyakov seemed much more morose and was found to be easily irritated by simple questions.
However, even if our Mars mission astronauts could talk to the outside world, by the time they neared mars there would be about a 22 minute delay between messages as radio signals can only travel so fast. With 22 minutes between each phrase, it kind of breaks the natural flow of communication so it would not be very fulfilling.
Sure we have plenty of spacecraft that are able to get to Mars and perform robotic duties, like with the Curiosity Mars Rover, but a manned spacecraft is something we do not have. Such a spacecraft does not exist, in fact currently NASA does not have any space shuttles that can ship man into space. A space shuttle capable of reaching Mars would need to be about the size of a small space station. That is if you do not want your astronauts getting the space crazies.
For one, people were not meant to spend long periods of zero gravity. Astronauts who spend excessive time in zero gravity suffer from muscle atrophy and osteopenia. An astronaut who is in space for about two month would be incapable of standing for more than a few minutes and would have to be wheeled around until they readapted. They would also lose 1% of their skeletal mass per month. An eight month journey to Mars would mess a body up. Even with the four to six hours of weight training that astronauts do in space to prevent muscle atrophy.
To solve these issues the space ship would need a huge centrifuge to generate artificial gravity. Like in 2001: A Space Odyssey. While scientists are working for several designs for ships that have this, the size of the ship and the centrifuge it would need would be expensive, so expensive.
Another worry for the space shuttle to Mars would be meteors. You may not see them but about 1 septillion meteors, rocks, and space sand particles hit our planet each day. Of course almost all of these are completely burned up in our atmosphere.
There is where we see a problem, during the long lonely journey through space, the space shuttle would not have out nice protective atmosphere to protect it. For example, too at our moon, all those dark patches are craters created from space junk hitting it because the moon has no atmosphere. A simple solution would be to add armor plating to the spacecraft. That would not only add to the incredibly high price of such a space shuttle, but it would also make the craft heavier. Since, as discussed earlier, we can only use rocketry to get into space, this would make it require so much more fuel to propel it.
Like everything in life, it all comes down to the cost. It cost us about 25 million dollars to get to the moon and that was in the 60's and 70's. Today the cost would be much more for the technology and the longer distance one would have to travel. Not to mention that there are a number of ways a manned mission could run into trouble deep out in space where no one would hear you scream. To prepare for any anomalies in the journey the space shuttle would have to be equipped to handle them. Considering the decline of the world's economy and the United States trillions of dollars of debt, funding a manned mission to be Mars would be nigh impossible in today's world of economic decline.
Considering a solid design for a shuttle that could make to Mars and back with a crew inside has not been designed there is not a good estimate of what that would cost. However, to get a rough estimate, let us look at the Mars Science Laboratory project, the project that landed the Curiosity rover on Mars in 2012. That project cost 2.5 billion dollars to complete. So creating an a much larger spacecraft that could support human life would cost at very least three times that. That is with the most generous estimates.