How does refueling work?

[HG_B]

The question might be how much pure water do you have to take out of the ocean to start playing with the eco system? You would start to increase the salt content after a while and possably lower the surface area.

A lot of unknowns I think.

Just Google for data on salinity density and what is too salty and do the math. It will be a ginormous amount. Far beyond thousands of years of ship refueling. But, in the long term, a concern for sure.

 

[shadowcat20]

For Earth maybe.

Planet X is 463555-B N

It has a navel base because it is a strategic location but no GG in system.

The assigned fleet is 1 batron of 2 tigress class ships, 1 batron of 2 100KT ships, 2 Crusron of 2 50 to 60KT ships, and 2 million tons of escorts, scouts, supply ships, tankers, and assorted normal merchant and logistics traffic.

Each time the fleet jumps out you are taking (jump 4 x 2 million tons) 800,000 tons of fuel. Now add dailey traffic to that. How long could that world sustain that type of loss? Now figure 4000 years of traffic for some systems. If the h2 is used in cooling then it may make it back to the surface over time. If not then it is lost and the planet gets drier.

 

[aramis]

Ummm...OK...Got most of that. It does mean however that a ship running out of air could be no issue if there is fuel stored as water.

The issue is running out of N2, more than O2. Crack a ton of ammonia, tho... (NH3) and it's 14/17ths Nitrogen by mass... liquid amonia is 683kg/kL at boil (-33.5°C at 1013mB, gas is 0.73 kg/kL at NTP (1013mB 20°C).

Liquid nitrogen is 808.4kg/kL in liquid at Std pressure and -195.8°C, 1.1651kg/kL as a gas at NTP.

So a Td of ammonia is 9.562Mg, of which 1.687Mg is hydrogen, and 7.875Mg is Nitrogen. Storing both as cryogenics... we get 1.687 Td H2, and 0.454 Td of Liquid N2. Expanding that to NTP we get some 6759kL, or 482Td, which, at 79% (the only trace gas really essential is CO2, and the life aboard will make that...) is sufficient for 611 Td of Std atmosphere... (1 Td of cryogenic N2 is sufficient for 1346 Td of standard mix, but needs 5267kg of 02, 4.617 kL cryogenic O2 or 0.33 Td.

In other words, we can store 901 Td of standard mix per Td as cryogenics...

And we then need 5kg more O2 per man-week...

Stashing spare atmosphere as water and ammonia is highly efficient by volume... but not by mass. Storing fuel as water and/or ammonia is efficient by volume, but again, not by mass.

Unless you need the nitrogen and oxygen...



http://www.engineeringtoolbox.com/ammonia-d_971.html
http://www.engineeringtoolbox.com/nitrogen-d_1421.html
http://www.engineeringtoolbox.com/gas-density-d_158.html

 

[shadowcat20]

This type of information is why I ask...

I suspect there are a lot of others who benifit from this also.

 

[rancke]

Stashing spare atmosphere as water and ammonia is highly efficient by volume... but not by mass. Storing fuel as water and/or ammonia is efficient by volume, but again, not by mass.

But due to the idiosyncracies of jump drive, volume is the critical resource. If you have to exceed structural strength, you can reinforce the structure or simply accelerate more slowly. As long as you gain more volume in savings than you lose for the reinforcement, it's an option that can be worth while. If your maneuver drive becomes slower because of the added weight, you can move a bit slower on the outbound leg (after jump you'll be rid of the extra weight). Possibly it will turn out not to be worth the extra expense on regular trade. But there are places where being able to make two jumps-4 will save you several to many jumps. At some point it has got to be worth it.


Hans

 

[E.D.Quibell]

As a gas at STP, however, that O2 is 9507.216 kL. Which is enough to completely replace the O2 in 45380.506 kL (3241.465 Td) of std atmosphere at STP. At 260 kg/man-year, that's 47.863 man-years of O2 per ton of water. Or 622 man-months using the std imperial calendar (4 weeks per month, 13 months per year, which matches the 4 week LS cycle).

Which is why you are not allowed to refine your fuel while you are in port

Best Regards,

Ewan

 

[HG_B]

The issue is running out of N2, more than O2.

You can always run it as the Apollo missions if no N2.

 

[aramis]

You can always run it as the Apollo missions if no N2.

Only Apollo 1 did that... with fatal consequences. WHile at lower pressures, it's less dangerous, it's still suboptimal.

 

[HG_B]

Only Apollo 1 did that... with fatal consequences. WHile at lower pressures, it's less dangerous, it's still suboptimal.

Agreed. Just as an emergency measure.

However, Mercury and Gemini used O2 (3 p.s.i.). Apollo 1 used O2 at too high of a pressure. THAT was the problem.