Rocket nozzles are a crucial yet complicated part of any rocket. Their job is to control the flow of exhaust so the rocket gets the maximum possible amount of thrust. This means that nozzles have to be very precisely manufactured, which in today's world usually means 3D printing.
Most commercial rocket nozzles are made of metal, which is difficult and expensive to 3D print but necessary for stability and durability. Any cheaper material like plastic would melt when exposed to the high temperatures of the rocket exhaust. Or would it?
MIT's Rocket Team decided to find out, and built a fully-functioning rocket nozzle entirely out of plastic. The rocket performed admirably and did not melt. The MIT team believes this marks the first ever successful test of a plastic nozzle.
The plastic nozzle didn't make it out of the test completely unscathed, however. The team reported that about 2 millimeters of material was eroded from the throat, which is the narrowest part of the nozzle. This erosion reduces the ability of the nozzle to produce thrust, and in fact a second test of the nozzle produced almost none.
That's not discouraging to the MIT team, which never intended for this nozzle to be fired more than once. Indeed, most commercial rockets—with a few notable exceptions—are only fired once outside of testing. Replacing these metal nozzles with plastic ones where possible could make many rockets just a little bit cheaper.
Source: MIT Rocket Team via Engadget
