I want to build a rocket powered vehicle capable of hovering at an altitude of 5 meters for 15 seconds, basically a smaller version of a Northrop Grumman Lunar Landing Challenge vehicle. The winning vehicles built by Armadillo Aerospace and Masten Space Systems both used a single, gimballed, LOX/alcohol engine, and my plan is to shamelessly copy their good ideas. Liquid fuel rockets are far less common than solids or hybrids in the world of amateur rocketry; just firing a liquid fuel rocket on a test stand is an impressive accomplishment. However, after reading and rereading the Masten, Armadillo, Unreasonable Rocket, and TrueZer0 blogs, I think a short duration hover can be achieved for a reasonable fraction of a grad student’s monthly stipend. I decided on 5 meters and 15 seconds after lots of research and some preliminary calculations. I don’t want to set an overly ambitious goal and waste money and time, only to have the project collect dust in a corner, and I think 5 meters/15 seconds strikes the right balance between challenging and realistic.