## 4 Discussion  
A system for deploying small satellites in LEO, in a range of 100-500 kg, has been proposed and studied at a conceptual level. The flying system is unmanned and remotely controlled; it is composed of a flying wing and a small launcher. The CAD visualization of the carrier-launcher system discussed in this paper is shown in Figure 24. The research proposed here has the aim of representing the first step in the development of a novel air launch system to be a candidate for a more effective and efficient solution, with respect to the current technical solutions. To do so, the first action needed is a conceptual feasibility study, focused on conceptual design and preliminary performance assessment of the concept.  
Figure 23: Sketch of Mode 6 (Flutter Mode) at Sea Level: 1.40 Hz.  
Figure 22: Graph of Frequency for the Unstable Modes (Cruise Condition).  
The main feature that distinguishes this air launch system from others existing in the technical literature [59] consists in the method by which the separation of the launcher from the carrier takes place. The separation between the two components of the system occurs during the execution of a parabolic manoeuvre that allows the internal forces, due to the gravitational effect, to be reduced to a minimum, thus simplifying the mechanical procedure for detaching the launcher. It has therefore been thought and verified that the launcher is released and ignites its own thruster, with a high speed and at an altitude of about 8000 m, at the end of a pull-up manoeuvre of the wing which performs a parabolic manoeuvre.  
A conceptual configuration has been defined at the end of a state-of-the-art study. The aerodynamic performance, the basic characteristics of the flight mechanics, and the aeroelastic behaviour have been preliminarily studied thanks to the use of well-known software (AVL [31] and NASTRAN [57]). The maximum take-off weight of the system, which can cover a long cruise range (about 8000 km) up to the actual launch area, is about 1200 kN. The weight is therefore much lower than that of other conventional configurations of air launch systems [42].  
As is well known, the stability of the flying wing can be a critical issue. In this work, it is demonstrated, at least preliminarily, that even in the most critical flight phase (parabolic flight) aeromechanical stability can be ensured using conventional control surfaces, without a strong reduction in lift-to-drag ratio.  
The safe execution of the parabolic manoeuvre requires the use of four high-thrust latest generation jet engines [56]. First-level analyses have shown that the system does not present evident criticalities due to forms of aeroelastic instability. However, further analyses are necessary to consider the effect of the launcher in a more realistic way, both from an aerodynamic and an inertial point of view. A non-secondary topic that certainly falls within the future developments of this research concerns the use of more reliable aerodynamic calculation systems (CFD methodologies) for a more in-depth study of the aerodynamic performance of the configuration, both at low speed (with a high angle of attack) and in transonic flight conditions. Another technical topic to be explored concerns the design of the system for connecting the launcher to the carrier. Among the technical requirements that this system will have to guarantee, the reliability and simplicity of execution of the separation phase of the launcher must certainly be considered.