[ RadSafe ] Mission to Mars

Brennan, Mike (DOH) Mike.Brennan at DOH.WA.GOV
Fri Feb 22 19:26:58 CST 2013 

I am very much in favor of establishing a Moon base before sending
people to Mars, as I am convinced we will learn really useful things we
don't even know we don't know, yet, just in the building.  Also, it may
be possible to put an elevator down to the Moon from the L1 point, which
would make getting down and back pretty easy.  And to date we've looked
at a couple of football-fields-worth (in either US fields or SI) of the
Moon, and it is dumb to think there isn't anything else there to learn
that isn't at least as interesting as Mars.

-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu
[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Robert Bradley
Sent: Friday, February 22, 2013 5:07 PM
To: The International Radiation Protection (Health Physics) Mailing List
Subject: Re: [ RadSafe ] Mission to Mars

Interesting ideas expressed here.  Would all of this be easier if the
moon was the main base?  Moving bits and pieces from lunar orbit does
suggest a more earth-protected approach.

-     -  RPB

On Fri, Feb 22, 2013 at 8:48 PM, Brennan, Mike (DOH) <
Mike.Brennan at doh.wa.gov> wrote:

> I, for one, would love to see you carry the Environmental Impact 
> Statement for capturing a rock that big and parking it in the near 
> vicinity of Earth.  If you do so, getting the people and equipment up 
> to modify it probably would cost as much as the proposed mission to 
> Mars (which, by the way, I disapprove of, because it is a political 
> stunt with almost no scientific merit.  At least in its current 
> Super-Apollo form).
>
> Be that as it may, the problem of moving that much mass remains.  If 
> you can't get the things you need to make a rock a home up there 
> cheaply, you can't move your rock to where you want it.  I personally 
> think you still need a space elevator.
>
> Having given it some thought, I've concluded that trying for 1g is 
> more problem than it's worth.  The rotational velocity needed to 
> produce 1g depends on the radius of your ship, but it is likely to be 
> inconveniently large.  I played with the calculus some time ago, and 
> found some entertaining things.  For example, if you are sitting down 
> and stand up, your inner ear moves closer to the axis, and experiences

> a different force than when you were sitting down.  I think it would 
> feel like you were in an elevator coming to a stop, but I would have 
> to see if I could find my notes.  There would also be a real force 
> experienced in the direction of rotation, and I think possibly a 
> torque perpendicular to it, but I don't recall what the numbers said.

> All in all, playing basketball in that environment would be a hoot.
>
> On the other hand, what's not to like about using nuclear explosions 
> on fast moving rocks?
>
> -----Original Message-----
> From: radsafe-bounces at health.phys.iit.edu
> [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Victor 
> Anderson
> Sent: Friday, February 22, 2013 4:23 PM
> To: 'The International Radiation Protection (Health Physics) 
> MailingList'
> Subject: Re: [ RadSafe ] Mission to Mars
>
> Good Afternoon,
>
> About that shielding thing:  Rocks my friends, big rocks.  You find a 
> rock in space that is about 300 to 500 meters in diameter on one axis 
> somewhere in the solar system.  Doesn't have to be a spherical object.
> Put said rock into a high orbit around earth with low yield nuclear 
> explosives.  Hollow the object out so that walls are about 10 meters 
> thick.  Reinforce as needed.  That should provide adequate shielding.
> If not, make them thicker.
> The next challenge is to design the ship so that it can be spun and 
> provide artificial gravity of about 1 g on the inner side of the
walls.
> Now install a nuclear rocket and go.  Use the materials you got from 
> hollowing out the new space ship in building same.  If you pick the 
> right rock, you may be able to sell some of the valuable minerals to 
> help fund your trip.  Trips via the surface of Mars and Earth will be 
> via shuttle craft.  Yes, this will be expensive.  However, the crew of

> the ship can be large and diverse enough that social-psychological 
> problems are minimal, if someone (gulp) dies, you can have a 
> replacement, and emergencies can be dealt with.  What will be 
> interesting is the radiation environment outside the ship and the 
> health physics for dealing with same.  My opinion is that such an 
> expedition should have a small health physics section.  Alright, who 
> has a few extra billions of dollars to fund the trip? :)
>
> Victor
>
> -----Original Message-----
> From: radsafe-bounces at health.phys.iit.edu
> [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Brennan, 
> Mike
> (DOH)
> Sent: Friday, February 22, 2013 3:12 PM
> To: The International Radiation Protection (Health Physics) 
> MailingList
> Subject: Re: [ RadSafe ] Mission to Mars
>
> I saw a presentation a couple of years ago that conclude that if you 
> could assume the passengers were 50+ year-old men, and shielded 
> appropriately, the trip was doable.  If, however, you had to design as

> if the passengers might be pregnant 20 year-old women, the shielding 
> would be too massive, and you couldn't build a ship that met the other

> requirements.
>
> I, personally, would rather continue sending SPECTACULARLY successful 
> robotic probes until a Space Elevator is built.  At that point the 
> cost to get mass out of the gravity well plummets, and all the 
> constraints for a ship that can get to Mars changes.
>
> On a related note, I've toyed with the idea of how you could use 
> nuclear power (more-or-less conventional reactor, rather than using 
> thermoelectric tech) in microgravity, I've pretty much concluded you 
> need to have it in a spinning ship, with the top towards the axis, and

> auxiliary equipment acting to balance the mass.  Quite possibly the 
> design you would wind up with is a disc, or saucer.  This would, 
> however not make for a ship you got to land anywhere.
>
> -----Original Message-----
> From: radsafe-bounces at health.phys.iit.edu
> [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Maury Siskel
> Sent: Friday, February 22, 2013 2:47 PM
> To: The International Radiation Protection (Health Physics) Mailing 
> List
> Cc: JPreisig at aol.com
> Subject: Re: [ RadSafe ] Mission to Mars
>
> I thought this trip remains beyond the shielding capabilities to 
> withstand irradiation exposure  --  has this changed?  Otherwise 
> sounds like a great adventure -- Dog also sez ok.
> Maury&Dog  [MaurySiskel  maurysis at peoplepc.com] 
> ========================= On 2/22/2013 12:55 PM, JPreisig at aol.com
wrote:
> > Dear Radsafe:
> >
> >       Hey All.  On US TV News today, Zubrin and  colleagues have
> announced a private effort to
> > reach Mars via spaceship or whatever.  The mission will start in
> 2018.  The trip will last 501 days.
> >
> >       Wonder if Maury and Dog will volunteer for the  trip???  Get
> your spacesuits and Geiger Counters  ready???
> >
> >       Regards,   Joe Preisig
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