Why do not humans to Mars

Since the planet Mars, humans have dreamed of boarded it. Recently, the human from the dream a step closer and more: "Mars exploration" organizations a project plan around 2030 send astronauts to Mars.Not long ago, at the call of the organization, scientists, the U.S. National Aeronautics and Space Administration (NASA) officials, a private aerospace company representatives and other members of the space community gathered in Washington to participate in called "Man on Mars" in the talks. Three days,Pretty Little Liars Season 3 DVD they discussed all human beings to Mars might encounter challenges.
Leave the Earth

Total first learn to walk before running, you want to in-depth exploration of space, you need to leave the Earth.While 50 years ago, we had to humans and space probes into space, but the production of manned spacecraft towards Mars remains difficult. Existing rockets can not carry such a heavy large spacecraft, astronauts, all supplies and fuel, and get rid of gravity to leave the Earth's surface.The most likely scenario is that the rocket flying through several times, and aircraft parts will be supplied loose in low Earth orbit. And little by little astronaut "pickup" They are assembled into new aircraft and eventually reach Mars.Currently, the largest man-made space equipment is the International Space Station, the total weight of about 4500 tons, the need to complete 31 spacecraft carrying. According to the U.S. National Aeronautics and Space Administration (NASA) calculations, a band of human and from Mars spacecraft will be smaller than the space station, about weight 1250 tons.

Serve on the Moon and Mars, NASA Space Center Comprehensive Research Department Brett Drake revealed that existing rocket to be launched 70 to 80 times, in order to assemble a reach Mars spacecraft. International Space Station took 10 years to build, assemble Mars spacecraft have to spend a lot of time.Fuel StorageManned Mars project, nearly 80% of the raw materials will be the propellant. The problem is that such a large amount of fuel storage is very difficult.When the spacecraft is in near-Earth orbit, will lap speed every 90 minutes around the Earth at half time experiencing hot, while the other half of the time and feeling cold. This alternating hot and cold will cause the evaporation of hydrogen and oxygen rocket fuel. The danger is that, if not regularly ventilated, these substances very easily explode.Hydrogen is particularly easy to leak,Pretty Little Liars the monthly loss of about 4%. If you need to stay in near-Earth orbit a year, it will lose nearly half of the propellant. This is an expensive waste because each into 1 kg of hydrogen into space will need $ 10,000.