A Fuzzy Velociraptor

The Sovereign Military Order of Malta is a recognized state whIch does not comtain any territory (though they did at one point). I cant imagine them ever recieving any sort of international recognition though.

I finally have power about thirty hours after literally almost everyone else in mainland daytona got power so yay. We did get quite fortunate the storm weakened and turned east.

The SpaceX reusibility and recovery thread a little further down already pretty much serves that purpose.

It's not free but it is nearly so. Generally with space launch vehicles the cost of the propellant would be negligible compared to the cost of all the other excrements that needs to go into the vehicle to make it work. In this case the additional energy to produce the propellant would be the only cost which while they would have to produce more propellant the cost would be so low compared to everything else that it would be essentially "free"

I agree but it is a very pretty video which I think is the point. I imagine the center ones would have to gimbal especially given what they show in their animation. For launch though the system is wide enough that they probably could just throttle steer which is tricky but not undoable or they might just have a couple of the engines on single direction gimbals that would angle them out to the side a bit to generate the needed torques. That is just an image for the sake of being pretty and to make it clear that you're far away from Earth and going further. There is nearly zero reason to gravity assist off the moon since you and the moon are both in the same gravity well (earth) trying to go to something outside the gravity well (mars).

Generally if you are going to deal with lower tolerances you want to have a larger engine so the relative tolerances are closer and use splash plate injector styles. It is fine to build at very small scales but you need to use certain manufacturing techniques.

Honestly your tolerances are so extremely loose that I'm not actually even certain you will be able to get high enthalpy supersonic flow. Now the effects of changing the size of your injector holes will depend on a number of things. The mass-flow rate could increase which would throw off your ratios, or the velocity could decrease which would decrease mixing and burn performance and would likely cause large combustion instabilities and coupling of the combustion with the feed system which is not desirable. If you wanted to maintain your mass flow rate you could want to create some way to regulate/choke the flow up stream though that will cause a severe velocity decrease which may prevent you from actually igniting. You could either try with trial and error or re-evaluate your construction techniques.

Atmospheric drag makes up a significant but still small portion of the losses normally between 200-400 m/s compared to gravity drag which is normally in the range of 1.5-2 km/s.

I'm not disagreeing with you there. I think I assumed you were just oversimplifying things.

They were also forced to use an engine Korolev didn't want to use for political reasons and Korolev was noted as saying it likely wouldn't be until the 10th launch that it would actually work. The flight testing was to debug the system. It does increase the chances of something going wrong, though it also reduces the impact of a failure. The engines themselves were unreliable and had acoustic problems which caused the pogoing that would cause some of the N1 failures. Other vehicles such as Soyuz which starts with 20 nozzles (not including Vernier engines) did not have those issues. However proton, especially in its early life is well noted for suffering from extreme unreliability. As for Black Arrow, the engines were noted to be the most reliable at the time, if not particularly powerful or efficient. Should you design a rocket with as many engines as the N1, no probably not, you're going to make the plumbing and control systems hell and you're probably not going to save any money but having that many engines is not a guarantee for failure.

I think what he means was that the system was not intended to be designed that it would have a high rate of failure like Aquarius.

Many textbooks on the subject will bring up optimization of rocket stages. For optimization it is generally desired for the non-propellant mass ratios to be the same for both craft. In the case that the effective velocity of both stages is the same the required delta V will be the same. This is generally not the case outside of textbooks or craft which operate entirely within one regime. Also there are many situations when designing to maintain similar mass ratios between the two stages may not be possible due to the non-linear weight-volume scaling relationships. However except in extreme circumstances (i.e. hydrolox or electric upper stage or solid lower stages) splitting the delta-V between the stages is normally a good first order approximation.

A full length spike... Clearly such a long thin thing won't have any sort of structural issues or logistical issues, and certainly having so much exposed area in our exhaust stream won't make cooling the thing a problem at all, especially when you consider all the benefits that a full length spike will give over a 23% "isentropic" aerospike like 1-2% higher performance (less if you dump a bit of exhaust into the center of the aerospike stream).

It did throw me off for a moment at the start though I had initially assumed it was hydrolox which turned out to be incorrect.

With the projector inside it wouldnt be hard to tell the projector to project a different image and you could keep it up longer.

Although there has not been an actual test of a depressed trajectory ballistic vehicle, there have been several papers on applying current vehicles to depressed trajectories and most hypersonic vehicle tests based off sounding rockets employ a depressed trajectory (source: Jess Sponable though I have been unable to find any text sources on thus). Also the issues you brought up are controls, heat transfer, and material problems which can be overcome.

While there are certainly problems with depressed trajectory systems, there is significant funding available to research and development for depressed trajectory systems.

By end of the decade do they mean 2020 or 2026/7? Because one is very feasible and one seems rather ridculous, While they are secretive, certainly, I do not think they can reasonably expect to complete such a large vehicle in three years time. It seems a very significant jump from their current capabilities (and hopefully they have a payload planned for it because there really arent a lot of things that would use such a vehicle that I know of). I suppose they could be doing the spacex thing of building hype and being singifcantly late on their promised delivery date. It looks pretty and I wish them luck but I am very sceptical. Also for the person questioning with the fins. Rockets in general are unstable and can be approximated as a reverse pendulum in terms of keeping them balanced, The center of pressure for most rockets is at or very near the nose. The fins in that case would not decrease stability because they would likely move the center of pressure back slightly, however the rocket itself spends little time in the atmosphere where aerodynamic stabilization is relevant that the fins make little difference.

Isnt that literally the entire point of insurance for satellites?

I would suggest you determine your chamber pressure and expected thrust. Your chamber pressure will be based off the pressure of the fluid you are putting into the system so it will likely be the same as your example. As for thrust if you decreased it by a factor of ten in each dimension you are likely looking at 1/100th the thrust but it should be noted that not everything scales well and combustion processes dont like to scale well. Though so long as you arent hoping for any level of performance it will still probably work. What are the size of your injector holes and your mass flow rates?

... That is really not how you should approach engine design.

What are you expecting for thrust and chamber pressure? Those are two pretty defining features that you normally start from but they dont seem to be listed.

The velocity would increase. In theory it should increase the convective coefficient; however you will be more likely to experience cavitation which is very not good. A lot of it depends on your geometries and pressures that it isnt easy to give a definate answer. With just a straight tube you will decrease the velocity significantly at the throat which could cause some material to be trapped which could result in boiling of the flyid which is also very not good. Ideally you will want to maintain a roughly constant velocity such that you would follow the curve somewhat but would fall away a little bit near the throat. Of course your system is a very simple/low performance engine that you are operating so youll have to apply my advice to that where I work on much more exact systems.

Air resistance is a very small portion of verlocity losses normally between 200-300m/s.

In general you will want to maintain a fairly constant velocity profile for a number of reasons. Since the density and massflux should be constant in order to maintain a contant velocity, a contant area is desired. As the radius decreases, the thickness in the annulus needs to increase. As a rough approximation you can consider the circumference of the annulus to be like the side of the rectangle and the thickness as the other. As the circumference decreases the other side has to increase to maintain area.