Today the access to space is done, only, by multi-stage rocket-powered vehicles, which have flown hypersonically, carrying their own propellant (solid and/or liquid, oxidizer along with fuel) to propel payloads and astronauts to Earth’s orbit.
The modern aerospace vehicles utilize multi-stage propulsion system on board, in general not reusable, of combustion chemistry (solid propulsion and / or liquid propulsion), extracting and converting chemical energy into kinetic energy with 97-98% efficiency. Approximately 89% of the weight of the spacecraft at time of launch, is due to the propulsion system be part of the vehicle , with only 1 to 2.5% due to the payload , usually satellites.
A new generation of scientific aerospace vehicles, using advanced hypersonic airbreathing propulsion based on supersonic combustion technology, is in development at several research centers . This new propulsion system (scramjets) is economically and ecologically more attractive than the conventional rocket propulsion.