On 4/30/2011 10:14 AM, David Spain wrote:
Pat Flannery wrote:
On 4/30/2011 7:29 AM, Val Kraut wrote:
One wonders what the plan is to keep the travelers from being killed
by radiation.

NASA tended to be in denial on this issue and made statements like
the Mars
crew will get their lifetime dose during the round trip - so no Mars
crews
will fly twice. What we need is th acceptance that shielding must be
provided asgainst both gamma and fast particles, and a realistic
allotment
for the extra weight. May need some different thoughts on where we
make the
fuel - Moon or Mars.

They played around with shielding the spacecraft with an electrostatic
screen:
http://www.msnbc.msn.com/id/5079651/...science-space/


But the article ends with a statement about surrounding the habitable
core of a Mars transit ship with tanks of LH2 or L-H20 to provide
shielding. If liquid water is used as a shield wouldn't it also need to
be heated while in transit to Mars? Or would pressurizing the water
tanks help? Or both? All it takes is energy, energy, energy.

Why does it have to be liquid? Ice would work as well, and make a great
micrometeor shield.


Back on topic for a second. Really, if Musk wants to go to Mars and HE
is footing the bill, he is free to try...


It does show that their very creative in what his team realizes Dragon
can do with its LES. The question is, did they plan for that from the
beginning, or realize it could do that after they decided on the escape
motors mounted in the capsule itself?
He may of gotten the idea from this Russian spacecraft design:
http://www.astronautix.com/craft/zarya.htm which used combo
escape/landing engines.

Pat