My question is about Mars-one's plan to send people to Mars in 2025. I want to know why it is a one-way trip and not a round-trip. People already landed on Moon in 1969 and successfully came back to earth. also NASA sent New Horizon in 2006. so the problem can't be about fuel technology. there's also no problem in escaping Earth's gravity, going to another planet, and landing successfully on Earth. so why they can't leave people on Mars and go back in 2 or 3 years later to pick them up? is the one-way trip a part of their plan or they're simply unable to make a round-trip between Earth and Mars? if so then why?
To fully answer your question requires giving you an enormous amount of background information.
The best explanation I have seen of this for the layman is astronaut Dr. Stan Love's presentation on why it is hard to go to Mars. Watch, be entertained, and learn.
Some highlights (these are not my points, they are his, so it is fruitless to argue them with me):
- Delta V for lunar mission = 42K mph, for Mars mission 48K mph. DeltaV is not the problem
- It took the Saturn V to launch 6 tons on a roundtrip lunar mission. A Mars mission would probably take 100 tons, or 25 Saturn Vs.
- We don't know how to keep the crew alive, healthy, and sane for the duration of the mission.