In-flight oxygen collection for a two-stage air-launch vehicle: integration of vehicle and separation cycle design

Abstract

In-flight oxygen collection is a very promising technique to reduce the launch costs and improve the payload capabilities of two-stage-to-orbit semireusable launchers. Using liquid hydrogen the incoming air is deeply cooled and enriched in oxygen during the cruise phase of the first stage. The liquified enriched air is stored in the second stage which is then launched into orbit. This paper gives the result of a conceptual design of a two-stage-to-orbit air launched space vehicle. The mass, aerodynamic, and propulsive characteristics of the first stage are determined and an assessment of the influence of the collection plant performance on the subsonic first stage is made. The results for a centrifugally enhanced destillation unit are given together with the plant cycle arrangement. Integration options for the plant into the first stage are proposed and a short description of the air separation test unit and its test bench is also given.