BillKerman1234

If we manage to make blueprints for a launch vehicle and satterlite, the getting then money is easy: just ask a university to sponsor us, and In return they get to have their students work on building an orbital rocket! I’m also a member of the British Interplanetary Society, so I could see if I can turn this into one of their technical feasibility studys.

- Aluminium sheets for the frame, 1mm thick and, say, 1*1m total surface area - Aluminium rods for the structure, 5mm wide, 5m long in total, cut into sections. - Aluminium spheres for RCS fuel, 20cm diamater - gold foil for insulation, 2*2meter sheet - Kale wool (a highly insulated material), 1*1m - Solar cells, 125mm^2 each, 20 - 30 pieces - ham radio, very high power - Li-po Battery, highest specs commercially available - RPi, gen 3 b+, with vacuum prof case (probably a cast resin block that we incase it with) - 2 Cameras (GoPro 6) incased in clear resin to space proof them - custom CNCed metal RCS thrusters - fuel tubing and fittings - spark generator (modified taser) for RCS igniter - RCS fuel valves and servos - accelerometers and gyroscopes - Wireing - a bunch of miscellaneous stuff I forgot

I would say if we’re going to make it recoverable, we should go with the ball shaped RV, but if it’s just going to be a normal satterlite, the a cubesat would be the best.

I came up with a few ideas: I’d say if we give ourselves 20kg of payload, that should be enough for whatever we want to do.

First off, a mult core design is vastly simpler than a ‘one on top of the other’ design (which is one of the hardest things to pull of in rocketry). Also, R-candy and model rocket engines. Seriously? The isp of those would be less than 200s! And while building our own solids might work, it would be very difficult. The easiest thing to do would be hybrids, but liquids would be even better. Also, just for the record, reaction wheels in real life are much less powerful than in ksp (even RO), so there not good for ascent guidance. RCS or exhaust tabs/fins are the way to go.

Good point, pressure fed would be much simpler than electric pumps (although I’m still not sure why building a simple impeller is so difficult). As for more liquid cores, I was thinking that the materials in the hybrids would produce much more thrust which is very useful for launch. Also, I know that this is not really a consideration in spaceflight, but liquid boosters have been done so many times that it would be very boring, sure we would be the first amateurs to launch a rocket into orbit, but it wouldn’t be that different from existing small-scale rockets like falcon 1 or electron (so much so that it might not be classified as a world record), however hybrids on the other hand have never been done before on an orbital scale (as far as I know). Not to mention that hybrids are (at least to my knowledge) cheaper than liquids, which is a major consideration if we want to ever use this to launch cubesats. Anyway, on another topic, have we fully decided how we’re going to reuse the stages? I’m thinking chutes for the booster (be them hybrids or liquids) and ballots + chutes for the core (which will go into orbit, so it will also need a heat shield and retro motors, though de-orbiting only takes 150m/s of delta v, so it’s not too much to worry about). Of course we could make the core expendable, but that means we have to build a new one every time we launch, which could quickly get very expensive.

Okay, so what if we use methane/lox with an electric turbo pump system, and strap on hybrid boosters? Sounds like a plan that could work! For guidance we could have static fins and mono prop RCS for higher up. The trick would be designing a biprop engine that actually works, and the hybrids could just be htpb and n2o.

Wumpus, I aggre with everything you said, except for the bit about it costing 6 figures. If we do it right, we could probably do it for under 100k, maybe 50k. The main cost driver in rocketry is the cost of hiring designers, the testing equipment, and most of all, the paperwork. Everything in a rocket (conventionally) has to be checked 500 times and must be traceable back to the ore in the ground. We can get around this by having a small non-payed design team, and using off-the-shelf materials and tools. A good example would be cubesats, everyone says scratch building one takes thousands of dollars using standard space rated materials, but if you just take a metal box and stick a RPi with some foam insulation and a battery inside, your pretty much done! The same applys to rockets, take SpaceX for example, by making everything in house, they reduce the cost by something like 70%. Think about it, what is a rocket? The fuel tanks are metal tubes with caps on the ends, the motor is a sphere with a funny shaped cone on the end, the fuel pumps are the same as you get in fire trucks (in fact there was a famous incident where von Brown was designing the V2 rocket and asked a bunch of pump engineers to design him a pump to some specifications only to have them all tell him that he was describing exactly a fire engine pump), and the guidance system can just be fins. Okay, I know this is vastly simplified, but when you think about it, there’s no real reason rockets have to be so expensive.

We probably can’t do bipropellent liquids, but if we can then yes, that’s probably what we would go with. And indeed, sea launch is by far the best option. Does anyone here know what it would take to build a biprop liquid engine? I’m curious how much more difficult it would be than a hybrid. In principle it should be easier to build a liquid motor, but in practice (from what I’ve heard) it’s far more difficult. Does anyone know why? Maybe we could have a LNG/NTO or a LNG/LOX core with hybrid boosters? Edit: I just realised liquid natural gas is also known as methane, in which case I would highly recommend a liquid core with hybrid boosters, as the core could have such a high isp that you wouldn’t need an upper stage.

Has anyone tried simulating the vehicle yet? We’ve basically finished the general design phase, the next step will be drawing blueprints, 3D modelling it, and doing CFD simulations on it. The first thing we should figure out is the optimum height to width ratio of the boosters and the core.

We could get away with nitrous, but then the boosters would need 2.8 tonnes of propellent, instead of 2.0 (assuming nitrous / htpb has 260s of isp). Personally, I still like HTP / Jellied Petrol.

Well, we don’t have to get the HTP from Australia, we could import it. As for nitrous oxide, although I aggre about it being easier to get and safer, and while I’m not sure if the isp of nitrous oxide / jellied petrol, it is almost certainly lower than htp / jellied petrol. Assuming we’re going with jellied petrol of course. We could go with htpb / nitrous oxide, but the isp would be lower, and the density would drop dramatically. Also, for the record, here is a better diagram of the rocket that I came up with (using a diagram from earlier in the thread for the Hybids).

Another question: does anyone know the mixture rato of jellied petrol / htp? I’m trying to calculate how big the rocket will need to be, but I need the volume of fuel & oxidiser, and in order to calculate that I need the mixture ratio. For now I’ll assume it’s 1:1

Okay, so then for now let’s assume we’re launching from Australia. Does anyone know how much delta v that will take? LEO is usually 9.5km/s, so 10? Also, has anyone tried simulating this in KSP realism overhaul yet?

Also, on another topic, does anyone here know how to 3D model stuff? I just figure that now that we have a good understanding of how we’re going to have it work, we should now start creating digital mockups of it for simulations. Or really just start putting it an any sort of blueprint form. I have an iPad Pro and an Apple Pencil, so I can draw 2D blueprints, but I simply don’t have the software or expertise for 3D design.

I’m not in any way an expert in law, but I’d imagine that no, it does not apply to foreign countries. If we were to build it in, say, somewere in the equatorial regions of Africa, it might be legal (I might be wrong though). And actually, that reminds me, did we aggre on where we would be launching from? I live in Britain and there’s currently a vertical launch site being constructed in Scotland, although I think it’s only being used by Lockheed Martin right now. Or maybe we should take a more traditional approach, and launch it from the Nevada desert (where most high power amateur rockets are launched), though if that would be legally possible I’m not sure. Also for consideration is Australia since sounding rockets have been launched from there every now and again and even also orbital rockets (the black arrow). Plus Australia is outside the US (although if something like ITAR still apples I’m not sure). The problem with Australia is it’s not equatorial. Of course we could always go with sea launch, although I’m not sure what regulations apply to that. It’s possible that if we construct it in a country where these laws don’t apply and then ship it out to the middle of the Atlantic Ocean we might be able to launch it without getting in trouble.

Oh wow, I didn’t expect a reply so quickly! Also, forgive me for being rude, but is anyone from the original thread still here (other than the moderators)? It’s just that no ones posted in half a year. Do you know why?

A few years ago this thread started. It looked at what it would take to get an amateur built rocket into orbit, and over time it evolved into a full blown feasibility study, and we got a few really good ideas and designs, along with some really good conversations, until late 2017, when it suddenly stopped. I was wondering if it would be a good idea to restart the thread again, and see if we can continue trying to come up with a rocket design that, one day, might actually get built. (Oh, and just for the record, I didn’t actually participate in the original thread, but I did read all of it) Since no ones touched on this in a while, I’ll start off the conversation. The consensus of everyone on the rocket design was to have ether a single core with 4 boosters and a upper kick stage, or, if that didn’t have enough delta v, 4 cores and 4 boosters with the same upper kick stage. The cores and boosters would be identical, using fins to steer in the atmosphere, while using RCS to steer in vacuum. The motors would be hybrids, running of a propellent that most people agreed would be some sort of htp/gasoline (I think). The RCS would be built into the core, and the side boosters would use the empty holes where the RCS would be on the identical core stage to mount gas thrusters to act as sep motors. The boosters and core would be recovered with parachutes. The upper stage would be a cluster of ether solid or hybrid motors. For simplicity it would have no guidance system other than gyros and accelerometers. Some people also suggested air launch from a ballon, but this was generally thought to be to complex. I propose that we use the same first stage design, and the boosters, but switch out the second stage to be a (very small, like just slightly larger than RCS sized) liquid engine running on ether methane/lox, gasoline/lox, or alcohol/lox (We could machine it with a lathe). It will be capable of thrust vectoring using simple hydrolic pistons to move the engine, and the fuel lines will be ether rubber tubes (which might turn brittle in space) or segmented plastic/metal tubes. The payload will be a cylinder covered in simple solar cells, (you can get them very cheaply on Amazon, though if they’ll survive space I’m not sure) and will contain ether a RPi or an arduino for control, with a series of accelerometers and mangatorquers for direction control. It would also have a very basic thruster (maybe ion? Check this out: https://m.youtube.com/watch?v=_TYvUdaLjRA, otherwise it could just be a CO2 cartridge with a valve) for station keeping. I’ve included some diagrams of the proposed rocket, and some calculations for it. As for cost, if we use standard aluminium sheets that we bend and weld into cylinders for the fuel tanks, and if we keep everything cheap enough, we could probably do it for 20k to 50k (maybe). Anyway, I hope that we will get some good conversations, ideas, and designs from this, and maybe, one day, someone will actually try to build it!

Is anyone still using this thread?