[ RadSafe ] Mission to Mars

Fri Feb 22 19:07:16 CST 2013

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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