Orbital fuel depot

On Saturday, April 12, 2014 6:18:40 PM UTC-7, Wrong Stuff wrote:
On Saturday, April 12, 2014 7:26:31 AM UTC-7, wrote:

On April 11 2014 19:34:44 UTC-4, Wrong Stuff wrote*:



I like the idea as it could be a component of a mobile industrial base.







Processing water from say the moon (if it has enough) and then as things unfold move the unit/module/processing base close to an icy asteroid.







I had in mind moving the icy asteroid or comet to LEO, or at least a big chunk of ice from it, rather than the eloctrolysing and liquifying plant to the asteroid. There are pros and cons both ways.







If you bring the plant to the ice you don't need to move rocks and dirt tied to the ice to LEO.







If you bring the dirty ice to the LEO, you don't need to have tanks with insulation and pressure valves to bring the fuel to LEO.







I think bringing the dirty ice to LEO orbit would be the best choice, but I would like to hear what others think of it.











Alain Fournier



I think it make more sense to go to mountain. I surely don't

want an asteroid close overhead. I'll bet things can go wrong

with that approach. It might approach a bit too close.



things go wrong and this should be planned for...........Trig

Parking it as into the surface of our moon would make all of its elements easily accessible.

On Sunday, May 4, 2014 7:20:31 PM UTC-7, Jeff Findley wrote:
In article ,

says...

In deed, human mistakes that again and again the fully interactive

computer engineered aircraft and/or spacecraft can be easily enough

discovered and corrected before it's prototype is ever constructed

and flown.



No, it's not "easy enough". It requires test flights and *lots* of them

and even then, bugs slip through and cause problems later. Software

isn't magic, it's lots and lots of typing by humans who make mistakes

and don't know what they don't know. Software is never perfect. If it

were, software companies wouldn't have bug tracking systems.



I happen to agree that custom air-breathing engines are not the way

to go, unless getting from the launch site to the equator is several

thousands miles.



And you have the numbers to back this up? It sure looks to me like

Skylon/SABRE is multi-billions of dollars and years away from a simple

test flight. Rocket powered VTVL stages are being tested by actually

flying today. I'll put my money on the stage that's actually flying,

not the one that's still a paper design.



Russia just packs bigger fuel tanks and uses more powerful rocket

engines and/or extra boosters in order to get the whole package to

launch from a northern location.



They pay a small payload penalty for launching from their more

northernly location, but it's not *that* bad. The payload penalty for

the shuttle to get to ISS was only bad for the shuttle because of the

need to put the shuttle's mass into orbit along with the payload. Soyuz

and Proton don't have this limitation.



Jeff

--

"the perennial claim that hypersonic airbreathing propulsion would

magically make space launch cheaper is nonsense -- LOX is much cheaper

than advanced airbreathing engines, and so are the tanks to put it in

and the extra thrust to carry it." - Henry Spencer

Supposedly our NASA/Apollo era tested and thereby having objectively proven everything necessary for fly-by-rocket treks and landers.

Are you suggesting that our Operation Paperclip run NASA and their Apollo era of supposedly walking on the moon was a ruse?

Computer engineered rockets and their fly-by-rocket landers and/or reusable components should be more than good enough as is, and easily scaled to suit.

Do you think SpaceX (Elon Musk) doesn't use computers?

Magnesium colloidally suspended in LOX creates a monopropellant with fairly high performance Isp=437.8 seconds or Ve=4,294 m/sec.

kg litres kg/litre

0.603 0.347 1.738 Magnesium
0.397 0.345 1.149 LOX
1.000 0.692 1.444 Combination

The lunar surface is comprised 7% of magnesium oxide. The electrolytic reduction of magnesium and oxygen from magnesium oxide is well-established

http://people.bu.edu/upal/pdf/SOM_Process.pdf

Here's a system that has a cell that produces 603 g/day Mg and 397 g/day Oxygen from 1 kg MgO per day using 6 kWh (250 Watts/cell). This is scalable up to 19 kg per day consuming 4.75 kW. This is less than 37% the size of a Solar Array Wing on the ISS. So, cutting the 12m x 37m wing down to 12 m x 12 m once deployed, achieves the power required for a lunar lander that processes magnesium oxide into elemental colloidal magnesium and liquid oxygen. At 100 W/kg the panel masses 47.5 kg. The balance of the system, 152..5 kg - a total of 200 kg payload.

Over the 13.661 days of sunlight on the moon this system produces 259.5 kg of propellant! Over a year 3,469 kg of propellant is produced by a 200 kg payload processing 22.5 cubic meters of lunar dust!

Lox/Mg fuel cells can also produce electrical power very efficiently. Companies already exist that use Magnesium Air Fuel Cells.

Propellant fraction of a 4.29 km/sec exhaust speed carrying a vehicle through a delta vee of 2.6 km/sec is;

u = 1 - 1/exp(2.6/4.29) = 0.4545

With a 14.55% inert fraction this leaves 40% for payload.

With 3,469 kg of propellant and a 45.45% propellant fraction take off weight on the moon is 7,632 kg. Payload is 3,053 kg - close to the payload of a DC-3. The inert mass is 1,110 kg. The cost of development is expected to be $77 million and each system $27.5 million.

An Ariane 5ECA, Atlas V 551, Delta IV-H, Falcon Heavy (development), H-IIB 304, Long March 5 (development), SLS Block 1 (development), are capable of putting this lunar lander on a Trans Lunar Injection.

Costs range from $60 million to $120 million per launch. The 200 kg payload requires a far smaller launcher. Landing a solar powered refinery on the moon, and operating it for a few months is the first step. This requires a smaller rocket, costing only $30 million to $40 million. Refilling the lander and sending it back to Earth with samples, is the next step. Landing 3,053 kg on the moon (without crew) refilling it, and returning the lander, is the next step.

$77 million - development
$83 million - fleet (3 landers)
$40 million launch (refinery)
$60 million launch (test flight/return)
$60 million launch (first paying flight)

$320 million total cost

16 passengers - $25 million each.

$400 million total revenue