Novel Fuel For Powering Your Way to Mars

Jochem Huhmann wrote:
Only if you want to change its orbit parameters or orbital velocity
(i.e.,altitude).


Like moving out of the path of orbital debris... And if you have the
station start slowly rotating after a botched docking or so you're very
soon out of options if you only have gyros.

In the first case you are right; it will indeed need a means of avoiding
orbital debris, and gyros can't do that.
But in the second case the gyros can indeed restabilize it by
differential braking of the gyro wheels.

The Hubble space telescope does a great job of aligning itself with
great precision via gyros, yet has no thrusters at all on it.
Bigelow's arriving tourist shuttles will certainly be the active
partners in the docking, and once attached can boost the space hotel to
keep its orbit from decaying due to air drag, in the same way the the
Shuttle and Progress cargo ships boost the ISS while attached to it.
The biggest problem that Bigelow faces is that its tourists are going to
get sick once they are up there, and once word about that gets around
that you are going to be spending a fortune to be turning green with
spacesickness,t he customer list is going to dry up in no time.


Well, someone not being impressed by all the other dangers and
inconveniences of spaceflight won't be much impressed by going a bit
green for a while, I suppose.


Oh it's not that...in space you don't throw _up_ you throw _out_ .
The vomit is going to form into droplets of various sizes, and there's a
real danger of inhaling some as it floats around.
If you could send people up there for a month or so, they could get over
the spacesickness in a few days and enjoy the rest of their stay on the
station (heck, the astronauts on Skylab were doing acrobatics after they
were up there a month or so).
But if you do that, you are very limited on the total number of tourists
you can fly in any year, and that's going to have repercussions on your
operating costs vs. profits.
The real problem though is that what seemed a very exotic thing to do in
the early days is going to lose its cachet as time goes on and
more-and-more people do it.
After a few years the fashion aspects of doing it will vanish, sort of
like climbing Mt. Everest.
Lord knows how many flags there are on top of it at the moment, but
their fluttering might well be affecting the jet stream over Nepal. :-D

The article states that this *is* working off the Environmental Control
Life Support System.

I don't think you do that via electrolysis though; I think that's done
via filtering and vacuum-distillation after centrifuging the solids out
of the waste water, not breaking it down into hydrogen and oxygen.


The article says "The innovative Orion Propulsion thruster system
uses hydrogen and oxygen that are produced from Bigelow's proprietary
Environmental Control Life Support System (ECLSS) as propellants for the
spacecraft's attitude control system." Sounds very much as if they are
producing oxygen from waste water for breathing and if you are doing
this anyway it's not a bad idea to expand the capacity a bit and also
produce oxygen and hydrogen for the thrusters...

It just doesn't make sense...hard as you try, you are going to lose some
water in the recycling process, as it's not going to be 100% efficient.
So now you've just taken some of your drinking water and turned it into
rocket fuel, so you are going to have to replace that, plus you are now
losing breathing oxygen also.
If you had sent up Lox and LH2 to the station instead of water, you
could not only have water, but electricity via running it through a fuel
cell and drinking the output, and the weight of the Lox and LH2 would be
the same as the same amount of water that is generated when they are
mixed in the fuel cells.
It would also be ready to use for the rocket thrusters, and by adding
more Lox than needed for the fuel cells or thrusters, having your
breathing air revitalized as well.
So what they managed to do is figure out a way to use electricity to
keep things operating rather than generating electricity as they keep
things operating.
It's like drilling the hole in a ship just under the waterline, and
generating electrical power by having the water stream fall unto a
paddle wheel deep in the bilge...electrical power that is then used to
drive a pump to keep the bilge dry and prevent the ship from sinking
from that leak in its side.
Okay, maybe the crew can urinate on the paddle wheel also to give it a
little extra velocity, but then their urine ends up in the bilge also.
Imagine a car that works like this...you tank it up with water, stick it
out in the sun, and a solar array on the roof generates electricity to
breaks the water down into hydrogen and oxygen - which then go to
storage tanks and from there to a fuel cell that generates electrical
power to drive motors on the wheels.
At some point it's going to occur to you that if you just hook the solar
array to a storage battery and the battery to the motors on the wheels,
things will work a lot more efficiently and be a lot less complex and
heavy - because you are losing energy at every step of the conversion
process, and you've just removed some steps and all the gizmos
connected with them.
You get oxygen and hydrogen together and they are going to _want_ to
combine into water and release a lot of energy as they do.
But once they are in the form of water they are not going to want to be
separated back into two different gases, which is why people don't get
blown to bits when they are making hard-boiled eggs. :-)
What Bigelow's concept reminds me of is the powerplant of the giant
Porsche "Maus" tank from WWII:
http://www.lonesentry.com/articles/maus/index.html
Here, a giant internal combustion engine drives a giant generator
mounted a few feet behind it...the generator in turn drives two giant
electric motors that are mounted a few feet behind _it_, and those in
turn drive the treads.
So you are taking rotational mechanical energy, converting it into
electricity, and then right back into rotational mechanical energy - all
in around 25 feet. :-D

Pat