S4 - A demonstrator of HYPLANE, a single stage suborbital spaceplane and a hypersonic business jet

The mid-to-long term perspectives of suborbital hypersonic spaceplanes require the availability of ultra-fast, winged vehicles, characterized by low wing loading, streamlined fuselages, sharp nose and wing leading edges, able to manoeuvre along flight trajectories at small angles of attack. From another point of view, the cost associated with sub-orbital space access flight is strongly conditioned by the still small dimension and uncertainties of its market. Therefore, hypersonic technologies and vehicle design suitable for the suborbital market as well as for point-to-point fast transportation can facilitate the endeavour. A high-speed business-jet is widely recognized to be more technologically affordable than larger aircraft and even more feasible from an economic point of view. Along this wave, HYPLANE is proposed as a 6-pax hypersonic business jet designed for P2P stratospheric transportation and suborbital flight at reduced ticket price. It will be based on more readily state-of-art available technologies like titanium alloys for its structure which are suitable to manage the levels of heat produced on external surfaces at those speeds and turboramjet engines, instead of less proven scramjets required for faster aircrafts. No disruptive or currently low TRL technology is needed, rather enhancing already available innovations. Attention is given to maintaining high level of environmental protection, especially in terms of sonic boom effects on ground, global and local pollution and noise emissions. To flight validate the system and related technologies, a multi-mission Single Stage Suborbital Spaceplane (S4) demonstrator is proposed. In parallel, the evolution of the Campanian Grazzanise airport to become a spaceport is being supported in the frame of a Suborbital TEst Polygon (STEP) proposed to be established between Campania and Sardinia regions. It will make available the perfect operational scenario where to test and make use of the S4 demonstrator