Okay, first of all: what the hell is a nuclear thermoelectric rocket? I won't give too long of an explanation, you can already find one in Atomic Rockets, ToughSF, and in this academic paper, but the TL;DR of it is that it achieves higher nozzle temperatures (thus higher exhaust velocities) without requiring hotter reactors. This gives you the relatively high Isp of low-end electrical drives and the high thrust of nuclear-thermal rockets without resorting to borderline clarketech like fusion drives and gas core drives. The most promising method through which this could be accomplished is having the propellant do two passes through the reactor. In the first, the heated propellant runs an electric generator. Since the generator is a Carnot cycle heat engine, this will cool the propellant down - though only to a point. In the second pass, the propellant is heated back up and vented through an expansion nozzle out into space, providing thrust - though not before an electric arcjet or magnetoplasmadynamic system re-injects the energy extracted from the first pass for an extra kick. Since the propellant doubles as coolant, this NTER needs no radiators.
My question here is: can this idea be expanded into a system that does three or more cycles through the reactor, with the energy from all the previous cycles being re-added into the end of last cycle where the propellant is vented out into space? Obviously adding more cycles would cause complexities and innefficies due to the Carnot cycle to pile up, leading to a point of diminishing returns, but where would that point be? At the 4th or 5th cycle, maybe?
Edit: from what I've gathered from some further digging I did on this, it seems the answer to my question would be no. Since each pass through the reactor would happen at a lower pressure than the last (this is the only way to cool down propellant in between loops without radiators), it would make more sense to have a higher pressure difference between the 1st and 2nd loop than having 3 or more loops wi
... keep reading on reddit ➡theoretically any flammable material would work in a hybrid rocket, so I was wondering if I could 3d print propellant grains for one. I'm thinking about using pet or petg plastic because its similar to the hdpe used for other hybrid rockets.
I am currently working on a mod with some others that is highly realism-based, (KSPIE) and I personally am currently working on adding some more fuel options so certain engines can be specialised for more uses. However, I am stuck on the Hybrid and Solid engines. Help?
My concept is near-future (so similar to current tech) lunar expeditionary war, the main power source for suits and vehicles is Hydrogen Fuel Cells, the cryo liquids are used for coolant, and the water byproduct is used for life support. The technology is capable of using solar power to recycle the water back into Hydrogen fuel so for most uses the suit is pretty much self-sustaining. However the vehicle rockets are mostly powered by Hydrolox engines, and the weapons use Hydrolox mixtures as propellant, so in this case the hydrogen/oxygen is a consumable.
*Apporoximately*, to the nearest tonne, how much Hydrolox fuel would a 1 tonne vehicle use to hover at the moon per minute?
*Approximately* how much Hydrolox is needed to fire a bullet at a decent velocity (~1000m/s)?
Would it be impractical to have the propellant stored as cartriges or should the weapon be fed via an umbilical connection to the suit? (The suits already have an umbilical to cool the barrel and provide HUD info)
I think it's more practical for larger calibre weapons, such as armoured vehicles, tanks, and emplacements, to use a mixture of chemical and electromagnetic propulsion, my concept is a Gauss barrel which accelerates a ferrous projectile which is initiated by a Hydrolox charge.
Reasons for using Hydrolox as the main propellant are that water is relatively abundant on the moon, carbon is very scarce. This makes gunpowder and other organic chemical alternatives impractical, plus all vehicles and suits will have a supply of hydrogen and oxygen for life support anyway.
Hey, I’m doing a project on composites for my engineering degree and have been basing it on design and construction of cryogenic tanks. Can anyone point me in the direction of good resources for such composite tanks?
I'm in a class about aerospace propulsion including air breathing systems, rockets, and some other propulsion. Today we talked about solid propellant rocket motors, and my professor mentioned that explosives are sometimes added to solid propellants. I've talked to him a bit more about it, and he said it's because of their energetically favorable properties. However, we also talked about how critically important the burning rate is for design solid rockets. I asked and he said they don't detonate in this case (of course, we also mentioned that rockets going boom = bad).
Most solid propellants are basically a rubber/plastic with oxidizer (ammonium perchlorate is common)/extra fuel (like a metal (usually aluminum) or explosives) mixed in. I'm confused about what part of this prevents detonation of the explosive itself. I thought it'd be that it wasn't in high enough concentrations throughout the substrate, but my prof said that wasn't it. I also thought that maybe it was temperature-insensitive explosives that're used, but then I wouldn't think it'd add energy to the burn, defeating the whole point of adding it in the first place. I don't know what explosives specifically are used. (Maybe I wasn't clear when I asked him about the concentrations).
Ultimately I guess I'm just a little confused, so I was wondering if anyone could give me a crash course in some explosive physics. I know a detonation is a supersonic propagation of the flame front, deflagration is subsonic, and that explosives need a critical mass and a shock (physical, temperature, etc.), both of which depend on the chemical, of some kind to actually detonate. Specifically, what lets us add explosives to a solid propellant while maintaining the ever important constraint that rocket = no boom?
Mods, if this is too unsafe you can take it down, makes perfect sense and I won't be mad
EDIT: PLEASE take it down if it is, I don't want anyone getting hurt from my post
Looking to get started putting in my form 1 for my 3rd book so I can start build it next year.
I’m looking at a para or commando version of the RPG7 or the Polish RPG-76
Both will require a more then 4 ounces of propellant
“The term “destructive device” means (1) any explosive, incendiary, or poison gas (A) bomb, (B) grenade, (C) rocket having a propellent charge of more than four ounces, (D) missile having an explosive or incendiary charge of more than one-quarter ounce, (E) mine, or”
The ammunition on both designs will use rocket motors(APCP), the RPG7 will also have a Pyrodex booster stage.
I’m debating if I need to form 1 per round, and whether I should leave the explosive check box unchecked since I won’t have an explosive payload above 1/4 ounce and neither propellants are considered explosives from my understanding.
Before I write to the ATF or just submit the form 1 per round, is there a NFA attorney that could help clarify what I am supposed to do in regards to a non explosive rocket but has over 4 ounces of propellant
Yes, you heard the title correctly. CLG(G) (Combustion Light Gas) cannons use a mixture of lox2 (liquid oxygen) and lh2 (liquid hydrogen) as a propellant for its ammunition.
4cm C.L.G Cannon (https://apps.dtic.mil/sti/pdfs/ADA462130.pdf)
This mixture is highly reactive and is significantly more powerful than conventional cannons. On top of that, it maintains stable temperatures while firing.
Although, there are issues with storing propellant. As it is reliant on making large explosions, it will fry the grew of a tank if given the chance.
Now, for sources and whatnot:
1.)https://www.youtube.com/watch?v=Axmmzf8Au0A (Spookston)
2.)https://apps.dtic.mil/sti/pdfs/ADA462130.pdf
Share your opinions!
For anyone not in the know, light gas guns are what NASA uses to simulate micrometeor strikes. They've been around for a lot longer than railguns and coilguns, operate at far lower temperatures than current magnetic weapons, and can accelerate projectiles to 11km/s and beyond while railguns struggle to reach 4km/s. Their main disadvantage, which keeps them from being adopted by militaries, is that hydrogen is terribly inconvenient to store, but if you're on an NTR warship, you'll already need to store H2 as propellant anyways, so why not use these guns?
If you take a look at the Soviet N1 rocket, it used spherical tanks in all of its first 3 stages and theoretically, a spherical pressure vessel has approximately twice the strength of a cylindrical pressure vessel with the same wall thickness, and is the ideal shape to hold internal pressure. Although nowadays rockets use spheres to store prop.; they are generally used for storing monopropellants, or liq. N2 for RCS thrusters of a rocket. But why doesnt anyone use spherical tanks as the main prop tanks in the main stages of a rocket ?
Not being able to throttle down or stop the reaction makes a small amount of sense to me, but what doesn't is why we cannot refuel them after they have been used.
Does using the rocket somehow destroy the components during use or is this mechanic to keep us from reusing the overpowered SRBs with gimbals on interplanetary burns?
It was called the SS67B-2 (later SS67B-3) and was made by a Canadian company called Systeme Solaire.
https://rocketdungeon.blogspot.com/2012/06/rocketaholic-provides-amateur-rocketry.html
http://pages.total.net/~launch/ss67b3.htm
http://www.ukrocketman.com/rocketry/liquids.shtml
From the outside, the SS67B-3 looked much like an ordinary high-power rocket; it was 4" dia. and about 6 feet tall. It ran on ordinary gasoline and H2O2, which were fed into the engine by pressure provided by a reservoir filled with dry ice (carbon dioxide).
According to the UKRocketMan article linked above, the SS67B-3's performance was mediocre due to a poor thrust-to-weight ratio. It depended on drag separation of the nose cone to deploy the parachute, which seems very dicey for such a large, heavy, and expensive rocket. Most people who built one probably chose to add an altimeter and ejection charge.
It's safe to say that Systeme Solaire didn't sell very many of these kits. The disadvantages were obvious: the $1098 price tag, the safety issues involved in handling hydrogen peroxide, and the fact that it couldn't be flown at NAR events.
Did anyone out there build one of these rockets, and if so, what were your experiences?
Aerojet nuclear Thermal Rocket specs and In-situ use of propellants📷
From the presentation: 2850K fuel temp, 893s Isp, 550MWt, 12.9kg/s and 113kN thrust.
Interrestingly, they discuss use of ammonia and as propellant as well: Isp of 360/315s respectively .
Hi guys! When I build my rocket, I have a question: "How many propellant I need to reach the orbit?".
Usually I take liquid fuel tanks randomly. But, I want to know exactly how many fuel I need.
Does anyone have formula to calculate this?
For example:
I have sputnik that have 10t mass. And I have engine that generate 300Kn force.
How many fuel I need to throw sputnik on Kerbal orbit?
From the presentation: 2850K fuel temp, 893s Isp, 550MWt, 12.9kg/s and 113kN thrust.
Interrestingly, they discuss use of ammonia and as propellant as well: Isp of 360/315s respectively .
