Two stage launch vehicle and launch trajectory method

Abstract

A method of launching a two stage vehicle and a trajectory for use with a two stage vehicle which allows recovery of both stages at the launch site. This is accomplished by launching the first stage completely vertically so that on burnout the first stage is positioned directly above the recovery site. In order to get maximum benefit from launching the stage vertically gravitational losses are minimized by a first stage thrust to weight ratio of 1.6. The high thrust to weight ratio results in burnout at approximately 100,000 feet altitude within the atmosphere. Therefore the vehicle employs engines which produce at altitude approximately 15 percent of the sea level thrust of the first stage and consume the last 5 percent of propellant over a time period of 40 seconds. Staging is accomplished at 200,000 feet altitude. The second stage employs uprated RL-10 engines and has a thrust to weight ration of 1.45 and can achieve orbit with a velocity change of approximately 24,500 feet per second. The first stage employs air breathing vertical lift engines for recovery. The second stage utilizes a parawing.

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