He turned to astronautics in the 1920s, corresponding with world leaders in this field, such as Oberth and Goddard and exchanging with them theories on interplanetary flight and its prospects.
He developed a special double-reaction engine, wrote extensively on multi-stage rockets and published two books on space travel.
Like many astronautic pioneers, he was a keen reader of Science Fiction literature and “in his backyard he experimented with the launching of rockets, single, multiple, loaded with ballast, registering their behaviour in flight, their ascent, more or less straight, and extracting theories from such observations” as his friend Luigi Rossetti reports.
He addressed a letter to the Italian National Center for Research, the historical Accademia dei Lincei and the Italian Society for the Progress of Sciences, underlining analogies between his writings and the experiments being performed in the USA at the time on multiple-stage rockets, spaceships spinning on their axes to create artificial gravity and the development of a solar engine to power spacecraft.
The spacecraft looked very much like an airplane fuselage, with a large disc attached to the forward end with vents which could be opened and closed to modulate thrust.
But actually in Gussalli's spacecraft, the thrust was not supplied by direct solar pressure 'blowing' the spaceship through space, as is envisaged in contemporary studies on a 'solar sail'.
The project was rejected as unfeasible by the British Interplanetary Society due to the impossibility of providing the required thrust, as well as by the USA NACA, that pointed out the difficulty of calculating (a) the right size of an efficient sail, (b) the exact amount of the 'dust' to be shot into space, and (c) the dispersion ratio of the particles.
In the same work, Gussalli suggested another innovative method to slow down spaceships on their way back to Earth: the aero-braking, widely used later on in aeronautics and astronautics, well after his time.
Such ideas, even allowing for inevitable mistakes and imprecision in a still computer-less age, show beyond any doubt that he had a 360 degree vision of the matter, anticipating in many ways future discoveries and applications.