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P-108 Icarus: Phase 2: Part 1

by on Jan.20, 2014, under Art and Designs, Musings, Software and Games

I have had some further ideas regarding this project.  Icarus turned out to be a very large rocket, much larger than I anticipated. It is also very complex, due to the fact that is uses liquid-fueled motors with cryogenic (LOX and LH2) propellant.

I want to know how small, and how simple, a rocket could be made to send a tiny payload (say, a USB memory stick) into space. I want to know if it is at all feasible to build a rocket powerful enough to reach escape speed with basic materials.

To simplify the Icarus project, in addition to reducing the payload capacity, I would use solid-fuel motors. This would eliminate the need for complex fuel and oxidiser feedlines, turbines, turbopumps, etc. Solid fuel rockets are much simpler to build, and homemade rocket fuel can be made relatively easily. The simplest type of homemade rocket fuel is “Rocket Candy“, Potassium Nitrate and Sugar (Sucrose).

The problem here is that solid fuel rockets in general, and solid fuel rockets using homemade fuels in particular, are less powerful than liquid fueled rockets. For this reason, medium to large rockets almost always use a liquid fueled main engine, possibly with solid fueled engines as boosters. Small rockets however, have been known to use solid-rocket engines exclusively.

The specific impulse of Rocket Candy is between 115 and 130 seconds, compared to 150 Р180 seconds for APCP (Ammonium Perchlorate composite propellant, used by the Space Shuttle Solid Rocket Boosters). This is surprisingly good, although, possibly not good enough for a ground launch to escape speed.

The next problem with building a simple rocket would be controlling it. Commercial space rockets use thrust vectoring, usually some kind of rotating gimbal mechanism. This kind of system would be much too difficult to build for an amateur. There are several other thrust vectoring options, (useful graphic here) such as Liquid Injection Thrust Vectoring, Hot Gas Injection, Jet Tabs, and Axial Plates. Axial plates and Jet Tabs are probably the easiest to build, since they don’t require modification of the engine nozzle itself, or any kind of extra fuel or related equipment.



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