Will we find Uranium In Space?

And will we develop an entire industry for radioactives processisng in
space? and what about the plutonium?

message #4548 Alex Michael Bonnici wrote:
>Some people within the space community have called
>for the development of nuclear rocketry (NERVA and
>PROMETHEUS) for the next wave of exploration of
>solar system.

Note that Prometheus didn't include NTR (NERVA). Only nuclear powered probes
and NEP.
Some call for even more radical extrapolations of nuclear powered space
travel, -namely nuclear pulse rockets (NPR), or Orion/Gabriel (EPPP or
external pulsed plasma propulsion)

>The question I have is this: Given the
>concerns of a possible Challenger style
>disaster and the possible consequences
>if such a disaster involved a nuclear
>reactor upper stage, wouldn't it be wise to develop this type of nuclear
>propulsion
>on the Moon instead?

I need to discuss several aspects of this.

Presumably this is to eliminate the danger of launching radioactives from
Earth?
Firstly, note that the crew of the Challenger 51-L (or some of them)
survived the break-up of their vehicle. They were going upwards when it
happened in a flash at ~9 miles up, and the G forces weren't sufficient to
kill them (in the opinion of a medical examiner). They arced up in the
broken crew cabin section, and fell back in from 12 miles, taking ~2.5
minutes from the time the aft ring of the ET broke free, starting the
breakup.
Hitting the water killed them. Accident investigators determined that there
was no blast damage on the pieces of the Challenger -it was torn apart by
aerodynamic forces, and the cloud of propellant released into the sky
experienced a rapid combustion -not an explosion.
Worms on the Columbia survived falling in from orbit -along with
recognizable chunks of their ship and bodies, crew uniform patches,
propellant tanks, etc.
Water tanks from Skylab were found in Australia, still recognizable. Falling
in from orbit is considerably more stressful than a booster breakup, and
even that wouldn't make a properly designed RTG or container break up or
vaporize.
The UK tested radioactive waste shipping containers by ramming the container
and the truck carrying it with a train...

Rocket booster parts fall in frequently, and many parts survive more harsh
treatment than what a booster malf would cause.
I think we can design RTGs, NTRs, and shipping containers for the Pu parts
of the mini-atom-bomb pits (to be loaded into the thrust-bomb cannisters for
a nuclear pulse rocket) so they'll survive to make a big smoking hole in the
ground in the case of an accident. Anything which might be hurt by any
little leakage will have been crushed by smoldering debris...
Launch engineers are typically more concerned with local wind direction
during a launch because then rocket fuels are highly toxic. They know that
the dangers of leaking radioactives from nuclear devices in launch accidents
are minimal.

Secondly, the Moon isn't any good for a deep-space staging area. Even if we
had tanks of pure LOX sitting there waiting for us there to fuel up, we'd
still need to go to more expense than simply leaving directly from LEO. I
suspect it'd be the same for fueling a nuclear engine from ready fissionable
fuel parts on the Moon.
Any rocket designed for liftoff from the Moon would probably be wasted in
interplanetary travel, and vice-versa; different demands dictate different
designs.
All we need is access to LEO. "Halfway to anywhere", as they say (It's about
time we got past the Shuttle).
Anyway, most nuclear power plants for spacecraft can be launched inactive,
so they're not a "hot" hazard until they're on their way. Fuel anything
dangerous up there.

In short, the perceived hazard of launching radioactives from Earth is
overblown.

>So here is my related question: What are the
>chances of finding reserves of Uranium ore on the
>Moon or asteroids?

Some asteroids have been processed by heat/pressure forces into nearly pure
nickel-iron, and they should have lots of uranium and thorium. Finding it on
the Moon would entail lots of prospecting, and you might not find anything
as good as ores on Earth. Meteor Crater in Arizona, USA was made by a
nickle-iron chunk, and there's no great lode under it -the impactors get
vaporized and all you get is high-iron content tectites. OTOH, the Sudbury
Astroblem in Canada was an impact, and it's yielded lots of good metals.
In any case, that's a long way ahead. All the industrial infrastructure we'd
need for fueling nuclear powered spacecraft is huge. Not that it's
impossible, but we've got a lot of work to do before we even start thinking
about that.

OTOH, getting the fuels for an upper stage is simpler by far.
Currently, for everything we send up to LEO with an upper stage for getting
to GEO or interplanetary space, fully 45% of the mass that we've shot up to
LEO is the oxidizer on the upper stage.
I haven't seen the numbers for an NTR stage; if it uses ammonia (NH3) then a
lot of it'll be fuel, H2 will be less, but very bulky -an "after-burning"
NTR engine which uses O2 for high-thrust/lower isp burns (such as a Lunar
shuttle) will suffer from launching oxidizer from Earth's surface.
I know that in an NPR (Orion) engine's pulse bomb units, fully 60% of the
mass is propellant, which can be plastics or other things relatively easy to
make from asteroids. Less than 10% of the mass is the Pu bomb pits.
Similarly, in the antiproton catalyzed micro-fission/fusion pulse rocket,
such propellants are the large portion of the rocketry mass.

Thus, the first thing we need to do, before going to Mars or back to the
Moon is go to an ice-rich or even stony NEA. Either simply capture it to
start bringing it back to HEEO for processing, or process the ices there, to
send back to LEO. Several times more payload set down on it from a given
rocket launched from Earth, many times better resources, many many times
more cargo sent back to users.

http://www.neofuel.com
http://www.permanent.com

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