[ RadSafe ] Mission to Mars

Fri Feb 22 19:44:38 CST 2013

Sitting outside (we live in the Caribbean now) looking at the sky with an
almost full moon, makes it hard to believe that establishing a moon base is
not the obvious next step.  Why would one not look to use the "vacant lot
next door"?

-     -  RPB
On Fri, Feb 22, 2013 at 9:26 PM, Brennan, Mike (DOH) <
Mike.Brennan at doh.wa.gov> wrote:

> 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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