Effects of different flight conditions at the release of a small spacecraft from a high performance aircraft
- Paper number
IAC-08.B4.5.4
- Author
Prof. Paolo Teofilatto, University of Rome "La Sapienza", Italy
- Coauthor
Mr. Luigi Ridolfi, Scuola di Ingegneria Aerospaziale, Italy
- Coauthor
Dr. Mauro Pontani, University of Rome "La Sapienza", Italy
- Year
2008
- Abstract
In recent years, mainly due to miniaturization of electronics as well as to improvement of computer performance, small spacecraft have increased their capabilities. More and more frequently specific mission objectives can be achieved with small, cheap satellites. The growing use of small satellites stimulates the development of systems specifically dedicated to orbit injection of small payloads. In this context, one option is represented by air-launched rockets. The use of an air-launched rocket for delivering a small payload into the desired orbit has several advantages. First of all, payload release is much more flexible, because the delivery conditions are directly related to the dynamics of the aircraft and can be viewed as independent of ground facilities. In addition, reduced costs are associated to the higher efficiency of an aircraft in the lower layers of the atmosphere with respect to traditional ground-launched rockets. To date, air-launched rockets separate from the aircraft in a horizontal flight condition. Then they maneuver in order to achieve the correct flight path angle for injection into a gravity-turn arc of trajectory. Relevant losses are associated to this pitch maneuver; in addition, in this phase the rocket usually needs an aerodynamic control. Hence, the release of a rocket departing with a high flight path angle from the aircraft would avoid these losses and would simplify the control system, because in such a situation the pitch maneuver becomes unnecessary. This paper is aimed at investigating the dynamic behavior and performance of a payload delivered from a high performance aircraft, which flies with a high flight path angle. In particular, this work is concerned with showing the differences and trade-offs among different starting conditions of a multi-stage air-launched rocket related to several flight path angles of the aircraft at release. An optimal system configuration, which allows placing a microsatellite into a specified low Earth orbit, is proposed. This configuration is selected by optimizing the release condition, the mass distribution among the stages, and the trajectory (through the identification of the optimal control law). This research also presents a configuration which can be implemented with some stages of existent rockets. This latter option implies a performance reduction, but allows decreasing the cost for rocket development and manufacturing, thus permitting a relatively inexpensive delivery of small satellites into low Earth orbits.
- Abstract document
- Manuscript document
IAC-08.B4.5.4.pdf (🔒 authorized access only).
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