farmerben Posted February 18 Share Posted February 18 It is challenging to keep liquid oxygen in space, you have to keep it chilled. Hydrogen peroxide decomposes on its own. Dinitrogen Tetroxide also seems subject to spontaneous breakdown, though I would like to know more details. Many cryogenic fuels have the same difficulties as liquid oxygen. Kerosene will probably last forever in a steel tank, but it probably needs to be warm to work. Hydrazine might be more stable than the oxidizers, but I'm not sure. What about solid fuel might be stable in space. I wonder if it is feasible to make solid rockets on the Moon or Mars? Mars exploration requires storability of 2 years minimum. It would be nice to have much more. Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted February 18 Share Posted February 18 (edited) 2 hours ago, farmerben said: Hydrogen peroxide decomposes on its own. 1% per year, as it was written in a space fuel paper we discussed here several years ago. Depends on concentration. HTP lasts long, the less concentrated - the faster decays. 2 hours ago, farmerben said: Dinitrogen Tetroxide also seems subject to spontaneous breakdown Is stored for at least a decade in the ICBM fuel tanks. 2 hours ago, farmerben said: Kerosene will probably last forever in a steel tank, but it probably needs to be warm to work. Is a mixture of various hydrocarbons with various properties, will probably last for several years, unlikely more. Also not sure if the valves will stay clean. 2 hours ago, farmerben said: Hydrazine might be more stable than the oxidizers, UDMH lasts for decades in ICBM tanks, preserves engines from corrosion in SLBM tanks. Hydrazine thrusters of Voyagers had been ignited after 37 years in space. 2 hours ago, farmerben said: What about solid fuel might be stable in space. May get cracked due to the temperature variations. Edited February 18 by kerbiloid Quote Link to comment Share on other sites More sharing options...
darthgently Posted February 18 Share Posted February 18 (edited) 3 hours ago, farmerben said: It is challenging to keep liquid oxygen in space, you have to keep it chilled. Hydrogen peroxide decomposes on its own. Dinitrogen Tetroxide also seems subject to spontaneous breakdown, though I would like to know more details. Many cryogenic fuels have the same difficulties as liquid oxygen. Kerosene will probably last forever in a steel tank, but it probably needs to be warm to work. Hydrazine might be more stable than the oxidizers, but I'm not sure. What about solid fuel might be stable in space. I wonder if it is feasible to make solid rockets on the Moon or Mars? Mars exploration requires storability of 2 years minimum. It would be nice to have much more. It is funny you bring this up because I've been mulling over if it could make sense to simply store water and carbon in a depot along with a reactor and/or lots of PVs and creating hydrocarbon fuel and LOX as needed. For hydrolox it would just be water. Long term storage mostly solved. Idk Edited February 18 by darthgently Quote Link to comment Share on other sites More sharing options...
JoeSchmuckatelli Posted February 18 Share Posted February 18 3 hours ago, darthgently said: It is funny you bring this up because I've been mulling over if it could make sense to simply store water and carbon in a depot along with a reactor and/or lots of PVs and creating hydrocarbon fuel and LOX as needed. For hydrolox it would just be water. Long term storage mostly solved. Idk I've been thinking along the same terms. Take something relatively stable and not reactive - and have the ability to create the reactive products required at the place we desire to acquire them. Pretty hard for the hydrogen to escape before you need it if its locked up in water ice until you need it. Quote Link to comment Share on other sites More sharing options...
magnemoe Posted February 18 Share Posted February 18 4 hours ago, kerbiloid said: 1% per year, as it was written in a space fuel paper we discussed here several years ago. Depends on concentration. HTP lasts long, the less concentrated - the faster decays. As I understand Soyuz capsule has an limited stay in orbit docked to an space station because Hydrogen peroxide decomposing. 4 hours ago, darthgently said: It is funny you bring this up because I've been mulling over if it could make sense to simply store water and carbon in a depot along with a reactor and/or lots of PVs and creating hydrocarbon fuel and LOX as needed. For hydrolox it would just be water. Long term storage mostly solved. Idk Problem is the power requirement converting it to fuel. But on an large base this is how you store bulk of it. Else I think you can solve at least oxygen and methane with sunshades and a bit of cooling. Quote Link to comment Share on other sites More sharing options...
DDE Posted February 18 Share Posted February 18 (edited) 8 hours and yet zero Ignition! quotes? Preposterous. Quote Rocket motors designed to operate only in deep space are generally designed to have a comparatively low chamber pressure — 150 psia or less — and it takes less energy to inject the propellants than would be the case with motors designed for sea-level use, whose chamber pressure is usually around 1000 psia. (In a few years it will probably be 2500!) And for the low injection pressure requirements of the deep space motors, some of the "space storables" seem peculiarly well suited. During the coast period, they could be kept below their normal boiling points. Then as the time for their use approached, a small energy source (a small electrical heating coil or the like) could be employed to heat them up to a temperature at which their vapor pressure would be well above the low chamber pressure of the motor, and could itself, be the injection pressure source, just as an aerosol spray is expelled by its own vapor pressure. Dinitrogentetrafluoride, nitrogen oxidetrifluoride, as well as the long known nitryl fluoride, FNO2, seem to be particularly suitable for this sort of application. Aerojet, during 1963, did a great deal of work along these lines, with complete success. It's a good idea, when choosing a pair of "space storables," to choose a fuel and an oxidizer that have a common liquid (temperature) range. If they are stored next to each other during a mission that lasts several months, their temperatures are going to get closer and closer together, no matter how good the insulation is. And if the temperature toward which the two converge is one at which one propellant is a solid and the other is a gas, there are going to be difficulties when it comes time for them to go to work. Likewise, if the self-pressurizing type of injection is used, design problems are simplified if the two have vapor pressures that are pretty close to each other. So, if the designer intends to use ONF3, with a boiling point of —87.5°, methane, whose boiling point is —88.6°, would be a good choice for the fuel. Two space-storable systems have been investigated rather intensively. RMI and JPL, starting in 1963 or so, and continuing into 1969, worked out the diborane-OF2 system, while Pratt and Whitney, Rocketdyne, and TRW, with NASA contracts, as well as NASA itself, have concentrated their efforts on OF2 and the light hydrocarbons: methane, ethane, propane, 1-butene, and assorted mixtures of these. (In most of their motor work, they used a mixture of oxygen and fluorine as a reasonably inexpensive surrogate for OF2.) And the hydrocarbons were good fuels, but methane was in a class by itself as a coolant, transpiration or regenerative, besides having the best performance. The OF2-methane combination is an extremely promising one. (It took a long time for Winkler's fuel of 1930 to come into its own!) Edited February 18 by DDE Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted March 3 Share Posted March 3 Amber. It's flammable. Its formula is C10H16O+(H2S). So, it can be used as a solid storable fuel for a hybrid rocket engine. It's highly storable. It stays unchanged for many million years. Quote Link to comment Share on other sites More sharing options...
darthgently Posted March 3 Share Posted March 3 39 minutes ago, kerbiloid said: Amber. It's flammable. Its formula is C10H16O+(H2S). So, it can be used as a solid storable fuel for a hybrid rocket engine. It's highly storable. It stays unchanged for many million years. Given that fuel production is more complex than mere fuel transfer I wonder if there will be a full time plant engineer position aboard orbital just-in-time fuel production depots with a very, very high hazard pay allowance? I'm old. I'd apply for it, lol. Catch up on my reading list between customers Quote Link to comment Share on other sites More sharing options...
Nuke Posted March 3 Share Posted March 3 (edited) On 2/18/2024 at 10:43 AM, JoeSchmuckatelli said: I've been thinking along the same terms. Take something relatively stable and not reactive - and have the ability to create the reactive products required at the place we desire to acquire them. Pretty hard for the hydrogen to escape before you need it if its locked up in water ice until you need it. ive always had this idea about snowball ships where your vessel is really just a large sphere of ice either artificial or using a natural body that is mostly ice. ice is mined on demand, cracked, and fed into an engine (which could be chemical but might be some kind of plasma, nuclear thermal or even fusion based propulsion). hab is in the center and is shielded pretty well from nasty space stuff and neutron flux coming off of the reactor. sublimation control i think is the big issue. may be suitable for long duration slowboat generation ships, given sufficient size. Edited March 3 by Nuke Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted March 4 Share Posted March 4 When you live on Alaska, everything around looks like a piece of ice... Quote Link to comment Share on other sites More sharing options...
Nuke Posted March 4 Share Posted March 4 2 hours ago, kerbiloid said: When you live on Alaska, everything around looks like a piece of ice... we hardly had any snow this year. Quote Link to comment Share on other sites More sharing options...
darthgently Posted March 4 Share Posted March 4 5 hours ago, Nuke said: we hardly had any snow this year. Alaska is a big state. Is this true if the north slope? Quote Link to comment Share on other sites More sharing options...
Minmus Taster Posted March 4 Share Posted March 4 Is it possible to keep propellant depots cool by shading then behind sunshields? That would allow you to basically have them everywhere in the solar system the shield can survive and operate. Quote Link to comment Share on other sites More sharing options...
StrandedonEarth Posted March 4 Share Posted March 4 28 minutes ago, Minmus Taster said: Is it possible to keep propellant depots cool by shading then behind sunshields? That would allow you to basically have them everywhere in the solar system the shield can survive and operate. Should be able to with a JWST-class sunshield. But that is multi-layered, and the biggest problem is preventing conduction from reaching the tank. Multiple sunshields for different directions would be needed to deal with planetshine Quote Link to comment Share on other sites More sharing options...
Minmus Taster Posted March 4 Share Posted March 4 1 hour ago, StrandedonEarth said: Should be able to with a JWST-class sunshield. But that is multi-layered, and the biggest problem is preventing conduction from reaching the tank. Multiple sunshields for different directions would be needed to deal with planetshine Is it possible you could avoid the planetshine issue by stationing the tanks at a planets L2 point? That way you could have a system where some tanks can be stored in orbit and regularly refueled incase someone needs them and the larger tanks can be placed at L2 for long range craft to use. Quote Link to comment Share on other sites More sharing options...
Nuke Posted March 4 Share Posted March 4 8 hours ago, darthgently said: Alaska is a big state. Is this true if the north slope? yea it is. im in southeast and we more lean towards rain that snow. there are parts of the state than never thaw out, but ive never been that far north. Quote Link to comment Share on other sites More sharing options...
PakledHostage Posted March 5 Share Posted March 5 19 hours ago, Nuke said: yea it is. im in southeast and we more lean towards rain that snow. Off topic, but from my own experience, they're vastly different. One winter about 10 years ago, I spent a month skiing in Alaska and then took the ferry from Whittier to Bellingham (with a 4 day layover in Juneau). Southeast was green and they had fresh food in the grocery stores (even in Yakutat, where we stopped for a few hours). That stood in sharp contrast to what we experienced further north. Back on topic: I posted this link a month or so ago: https://www.nasa.gov/general/electro-luminescently-cooled-zero-boil-off-propellant-depots/ Maybe the technology offers a solution for orbital fuel depot aspirations? Quote Link to comment Share on other sites More sharing options...
magnemoe Posted March 5 Share Posted March 5 On 3/4/2024 at 5:37 PM, StrandedonEarth said: Should be able to with a JWST-class sunshield. But that is multi-layered, and the biggest problem is preventing conduction from reaching the tank. Multiple sunshields for different directions would be needed to deal with planetshine Yes but planetshine is much weaker even from earth in LEO. Say an two layer from earth, you will also need to insulate this from the warm part of the ship that is the docking port and the controls, web also have to deal with this. Also as this is heavy you are not as weight restrained as web. Quote Link to comment Share on other sites More sharing options...
Nuke Posted March 5 Share Posted March 5 4 hours ago, PakledHostage said: Off topic, but from my own experience, they're vastly different. One winter about 10 years ago, I spent a month skiing in Alaska and then took the ferry from Whittier to Bellingham (with a 4 day layover in Juneau). Southeast was green and they had fresh food in the grocery stores (even in Yakutat, where we stopped for a few hours). That stood in sharp contrast to what we experienced further north. Back on topic: I posted this link a month or so ago: https://www.nasa.gov/general/electro-luminescently-cooled-zero-boil-off-propellant-depots/ Maybe the technology offers a solution for orbital fuel depot aspirations? i did live in anchorage growing up and yes its a completely different beast. on a road trip to fairbanks i was amazed at how hot it got there in the summer time it had to be over 90 freedom degrees there. of course i wasn't about to winter there. as for fresh food in the grocery stores, lol, nope not any more. Quote Link to comment Share on other sites More sharing options...
magnemoe Posted March 5 Share Posted March 5 39 minutes ago, Nuke said: i did live in anchorage growing up and yes its a completely different beast. on a road trip to fairbanks i was amazed at how hot it got there in the summer time it had to be over 90 freedom degrees there. of course i wasn't about to winter there. as for fresh food in the grocery stores, lol, nope not any more. How many people know anchorage outside of Fallout 3 And yes that game also ruined Washington DC for me, Quote Link to comment Share on other sites More sharing options...
mikegarrison Posted March 7 Share Posted March 7 I know a guy who was a professor at UAL-Fairbanks for a while. Got a lot of ice climbing practice in the winter. Quote Link to comment Share on other sites More sharing options...
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