[Walkingfeather]

Problem.... Cosmic radiation. You might leave for the mars but you would never make it. In order to protect you from the bambardment of CR your ship would have to be several feet thick of lead. Lead is still a bit heavy as far as I know. Hard to get it into space with that kinda weight.

[muir_redwoods]

Why would you need several feet of lead for radiation protection? Surely an inch or so would be more than adequate and more sophisticated shields would require even less.

How does the space between Mars and Earth differ dramatically from the space between Earth and the moon? How about the people who spends months in the orbiting space stations?

Do you seriously feel that such a trifling problem will keep us away from Mars? Really?

[Wonder Warthog]

"Problem.... Cosmic radiation. You might leave for the mars but you would never make it. In order to protect you from the bambardment of CR your ship would have to be several feet thick of lead. Lead is still a bit heavy as far as I know. Hard to get it into space with that kinda weight."

Dear Feather--I have a revelation for you---you are bombarded daily with cosmic radiation--the atmosphere is no barrier to it. The only way to escape it is by being several hundred feet underground. The problem with space travel isn't COSMIC radiation (which is omnipresent, but at a relatively low dose level), but the probability that SOLAR radiation (particles emitted from the sun during solar flares) will suddenly increase. As abwehr says--the answer to that is the small, well-shielded "solar storm cellar".

[SolitaryMan]

You gotta think outside the box. You could do multiple launches and assemble the spacecraft in earths orbit, sort of like the ISS.

[Skibane]

In order to protect you from the bambardment of CR your ship would have to be several feet thick of lead.

Or several yards of water — Might come in handy on the trip anyway!