If the next trip to mars that NASA do they should take up lots and lots of green house gasses. The green house gasses would create an atmostphere on mars and this would also keep heat in. Then NASA should take lots of plants to mars so that they can turn the vast amounts of carbon dioxide to oxygen so human beings can breath. Once the plants have created oxygen take water up and humans will be able to survive.

something like this?

they already plan to put lots of plants because there is a TON of carbon dioxide in the atmosphere there. The plants would help produce oxygen, but then we also need nitrogen. Our air is composed not only of oxygen, just we USE the oxygen. If we go to Mars and dump a ton of oxygen, it become toxic.

The problem is that Mar's atmosphere allegedly isn't thick enough to hold much heat, so the plants would simply freeze and die.

As for taking greenhouse gasses, it's not like we can just pack them in a suitcase. They have to be compressed, stored, hauled, etc. which means lots of fuel and lots of money, plus if we expected to put Earth's atmosphere on Mars to make it more liveable, that would be taking away from the atmosphere we have (obviously), therefore making Earth less habitable.

as for the plants they could go very well protected and then as for N2 we could just send some of ours for the time being bcoz we have loads, plus they should obvoiusly start with a closed envoirement expanding afterwards!

The problems are:

1) You may be thinking that plants only need Oxygen. , but let me tell you that the plants need oxygen for its respiration all day. The only thing they do on earth is that they give out more Oxygen than the Carbon-di-oxide. This is not possible on Mars coz the major content up there is CO2.
2) The normal temperature in the lower atmosphere is about 200 Kelvin, which is generally cooler than the average day time surface temperature which is around 250 K.
3) The powerful sun rays (due to absence of atmosphere) may cause mutations in the plants up there.
4) Plants on Earth are adjusted to the physical and chemical conditions of Earth through mutations. But if a plant was to adjust itself to mars then, it will just die (of continuous mutations).

The Viking experiments found no persuasive evidence for life on the surface of Mars.

But on account of my imagination, I sometimes think that mars was once like our beautiful Earth.
People polluted the environment, the level of CO2 increased until the percentage was so large that it ultimately ended life on Mars. And it is Earth’s turn now…

Alan, maybe I completely missed what you're trying to say, but if I didn't, I see a few problems with your statements.

1) Plants take in carbon dioxide and give out oxygen, so there wouldn't be a problem with the CO2 content, although there may not be enough nitrogen in the atmosphere to support plant life.

2) Yeah, I'd say that 200K is usually cooler than 250K, unless special circumstances apply.

3) Mutations due to radiation aren't as common as science fiction makes them seem. More likely, the plants would simply die from the radiation, not mutate into some form of super-plant, like what happens in the science fiction movies of the '60s.

4) The plants wouldn't die of continuous mutations, they would just die of a lack of necessary nutrients and chemicals to keep them alive. The soil of Mars would probably be very high in radiation and low in nitrogen and other necessary nutrients, since, as far as we know, there was never any life on Mars (and as such, no organic material to feed the plant), plus the extreme temperatures would be too much for most kinds of plants.

They would be beter off using water for air - If you apply a large amount of electricity to water, it will release oxygen, and with so little pressure on mars, oxygen would be safely breathable! Also, you still have the water to drink, and live. But call idea, and cool thread!!

As it was said, aside from needing CO2, plants also need something to eat, minerals and other nutrients... If we were to take just any plant to Mars, and put it there, it would simply die, plain and simple... It just wouldn't work...

What my idea was (and still is), and I'm sure NASA brains are also thinking of it, is to create a form of bacteria, that would use CO2, to create Oxygene, or perhaps just to create some sort of nutrient in the soil... Ofcourse, terraforming a planet is a long tie process, which would probably take a 100 years or more, to accomplish...

For now, I can only see glass domes on Mars, where people will live in colonies, while thebacteria, the plants, and who knows what other tech, terrafroms the mars into what we need to live...