A rockoon closed helium buoyancy system; a first assessment

Abstract

It is believed that the use of rockoons will revolutionize the space industry by giving priority service to microsatellite developers that now are secondary payloads for large rocket companies. However, stratospheric balloons, including rockoons, are typically filled with helium, the price of which has been rising sharply in the last decade, and if the tendency continues the use of helium in this technology could be seriously compromised. Here, we present a first assessment of the possibility for a helium closed buoyancy system in which helium is stored in a pressurized tank attached to the stratospheric balloon and pumped into the balloon and back by means of a centrifugal pump. Preliminary reckoning shows that by using a carbon-fiber-reinforced polymers (CFRP) composite as material for the storage vessel, a vessel diameter around 4.5 m will be necessary to transport a small rocket with a total mass of 150 kg. A helium closed buoyancy system will allow not just saving helium but also controlled buoyancy during lifting and the landing