Is spaceship fuel like gasoline?

[palebluevoice]

Of course it isn't; what I mean is, I know you're not supposed to store vehicles with gas in them; or if you do, you'll have to replace the gas/richen the mixture to make the engine run properly.

Blindly translating this same habit to orbiter, I always drain fuel at my terrestrial bases; and fill my vessels when I'm ready to take them out. I imagine there's somewhat of a safety advantage; but then again, I'm just moving it from one tank to the other, when similar design specifications.

To drain or not to drain? That is the question.


Also, since this is a theoretical question and not relevant to gameplay, I thought it belonged in this forum rather than orbiter questions.

 

[N_Molson]

Well, it depends, really... Chemical rockets are fueled only of the pad ; SRMs or solid rocket stages have to be assembled at the factory with the powder inside and can't be emptied ; fictional advanced spaceships like the DG probably have "fusion power generators" that should be pretty durable... But still, that power device needs a fuel, maybe something like xenon gas... It seems to make sense to defuel is the DG isn't going to be used for an extended duration. :2cents:

AFAIK, the Shuttles tanks were carefully decontaminated and thoroughly cleaned up between flights.

 

[Hlynkacg]

Depends on the fuel.

If you're using a Nuclear powered VASIMIR or NERVA type engine no. Your fuel is nothing like gasoline because it is a solid block of Uranium or Thorium.

Your propellant of course is whatever fluid is most convienient.

If you're talking about KeroLOX and other hydro-carbon based chemical boosters (such as the Saturn V's first stage) your fuel is exactly like gasoline.

 

[jedidia]

Also, if your propellant is LH2, you'll have severe trouble storing it inside the spacecraft when it is parked in an atmosphere. If you power down the vessel, the hydrogen will evaporate due to cryogenic storage being offline. So yes, in most cases it's certainly the best idea to drain, if only because the thing will have to go through several maintenance checkups, whic is always easier to do when it is empty.

A purely interplanetary craft parked in Orbit might be another matter. Its storage capabilities should be just as adequate as that of a space station. But again, if you have to power the whole thing down for a reactor overhaul or somesuch, you don't want your cryogenic propellants to increase the matter density of the surrounding space by an insignificant fraction...

 

[palebluevoice]

Well, it depends, really... Chemical rockets are fueled only of the pad ; SRMs or solid rocket stages have to be assembled at the factory with the powder inside and can't be emptied ; fictional advanced spaceships like the DG probably have "fusion power generators" that should be pretty durable... But still, that power device needs a fuel, maybe something like xenon gas... It seems to make sense to defuel is the DG isn't going to be used for an extended duration. :2cents:

AFAIK, the Shuttles tanks were carefully decontaminated and thoroughly cleaned up between flights.

Yes, I should have specified; the delta gliders and XR vessels(for the most part); good, I'll maintain my procedures for those.

Depends on the fuel.

If you're using a Nuclear powered VASIMIR or NERVA type engine no. Your fuel is nothing like gasoline because it is a solid block of Uranium or Thorium.

Your propellant of course is whatever fluid is most convienient.

If you're talking about KeroLOX and other hydro-carbon based chemical boosters (such as the Saturn V's first stage) your fuel is exactly like gasoline.

Hah, I had no idea the Saturn V ascent stage had kerosene in it. The same dinosaur bones in my grandpa's old lamp took men to the moon...

Okay, so for non-combustive engines it doesn't matter if you're shooting dead pepsi or water(well, density, reactivity and such, I get that, but the composition doesn't matter)...I'll assume all my psedo-infinite delta V craft are nuclear; so I don't need to worry about those...great!

Also, if your propellant is LH2, you'll have severe trouble storing it inside the spacecraft when it is parked in an atmosphere. If you power down the vessel, the hydrogen will evaporate due to cryogenic storage being offline. So yes, in most cases it's certainly the best idea to drain, if only because the thing will have to go through several maintenance checkups, whic is always easier to do when it is empty.

A purely interplanetary craft parked in Orbit might be another matter. Its storage capabilities should be just as adequate as that of a space station. But again, if you have to power the whole thing down for a reactor overhaul or somesuch, you don't want your cryogenic propellants to increase the matter density of the surrounding space by an insignificant fraction...

I hadn't even thought about cryogenics, thanks for pointing that out...even worse, if the tank is well sealed, the pressure could build and go boom, right?

This is interesting discussion, thanks everyone!

 

[jedidia]

I hadn't even thought about cryogenics, thanks for pointing that out...even worse, if the tank is well sealed, the pressure could build and go boom, right?

Not sure. I would exect any decent tank to be capable of keeping the hydrogen liquid if it was that perfectly sealed, and somebody forgot to build in an essential valve. But the trouble with hydrogen is that you can barely keep it in the tank even if the temperature is low enough, the stuff keeps evaporating into space even then.

 

[T.Neo]

Note that various space probes, satellites and some manned spacecraft (such as the ISS, specifically the Zarya and Zvezda modules) operate for years or even decades with hypergolic propellants inside them.

Cryogenic propellants (such as LOX, LH2) are fundamentally different from gasoline (or other 'room temperature' propellants such as RP-1 or hydrazine) in that they will boil off over time. This will happen in space (where the 'only' source of heat to boil away cryogens is radiation from the sun or nearby planets, save for onboard sources such as warmer sections of the ship) and on planetary surfaces (where heat can conduct in from the surface and atmosphere as well). You'll have to vent away the accumulating gases to keep pressure inside the propellant tanks at measurable levels. If you are in a thick oxygen atmosphere (like that of Earth), you will probably have to flare off hydrogen (i.e. burn it) to prevent an accumulation of flammable gas (the shuttle transports hydrogen boiloff through a vent arm to a flare stack elsewhere at the launch site).

Whatever propellant you're using, you will probably want to transfer it to some sort of safe storage rather than just dump it onto the surface (doing so with kerosene would not be very environmentally friendly, doing so with hydrazine or similar would be criminal). Not only could surface facilities be superior for storing propellant, but the propellant in question may be fairly valuable (at least from the standpoint of an off-Earth base).

 

[palebluevoice]

Note that various space probes, satellites and some manned spacecraft (such as the ISS, specifically the Zarya and Zvezda modules) operate for years or even decades with hypergolic propellants inside them.

Cryogenic propellants (such as LOX, LH2) are fundamentally different from gasoline (or other 'room temperature' propellants such as RP-1 or hydrazine) in that they will boil off over time. This will happen in space (where the 'only' source of heat to boil away cryogens is radiation from the sun or nearby planets, save for onboard sources such as warmer sections of the ship) and on planetary surfaces (where heat can conduct in from the surface and atmosphere as well). You'll have to vent away the accumulating gases to keep pressure inside the propellant tanks at measurable levels. If you are in a thick oxygen atmosphere (like that of Earth), you will probably have to flare off hydrogen (i.e. burn it) to prevent an accumulation of flammable gas (the shuttle transports hydrogen boiloff through a vent arm to a flare stack elsewhere at the launch site).

Whatever propellant you're using, you will probably want to transfer it to some sort of safe storage rather than just dump it onto the surface (doing so with kerosene would not be very environmentally friendly, doing so with hydrazine or similar would be criminal). Not only could surface facilities be superior for storing propellant, but the propellant in question may be fairly valuable (at least from the standpoint of an off-Earth base).

Oh yes, that's what I meant. It's been a while since I've used my setup base, but I'm pretty sure I used fuel or refuel mfd to "transfer" it to the UCGO trucks...or maybe I just dumped it with fuel trucks nearby. Regardless, I'll get my hands on a couple of old shuttle tanks and use those.

 

[Tychonaut]

Just make sure you don't dump the fuel if you're using one of these. Any way you exhaust that other than rocketing it into deep space at greater than solar escape velocity is sure to annoy someone. If you drain it, be very careful what you drain it into.

For nuclear thermal rockets, remember those uranium fuel rods require cooling for years after shutdown. You'll need a separate cooling loop when the rocket is not operating. This would hopefully not try to draw coolant from empty reaction mass tanks.

Hah, I had no idea the Saturn V ascent stage had kerosene in it. The same dinosaur bones in my grandpa's old lamp took men to the moon...

Kerosene is still a common rocket fuel today, used in the Atlas V, Falcon 9 and Soyuz rockets. Probably others I've forgotten, as well.

 

[TMac3000]

I always defuel my XR-5 before landing. And in the future, I'll be launching an XR mission to check out my Arrow before sending it on a flight.

 

[Screamer7]

And what about the descent and ascend stages of the LEM.
What type of fuel did they used.
I think I read some where it used Hydrazine, but I do not know it's properties.

 

[Tychonaut]

And what about the descent and ascend stages of the LEM.
What type of fuel did they used.
I think I read some where it used Hydrazine, but I do not know it's properties.

The LM used [ame="http://en.wikipedia.org/wiki/Aerozine_50"]Aerozine 50[/ame] as fuel and [ame="http://en.wikipedia.org/wiki/Dinitrogen_tetroxide"]N2O4[/ame] as the oxidizer. Aerozine 50 is a mix of hydrazine and UDMH. As T.Neo noted, this is toxic stuff, but storable for long periods without the worry of boiloff. Also [ame="http://en.wikipedia.org/wiki/Hypergolic_propellant"]hypergolic[/ame] with N2O4.