On 21 June 2017, Airbus Safran Launchers, ArianeGroup began development of a full-scale prototype of an ultra-low cost engine demonstrator, #Prometheus, using liquid oxygen–methane propellants. The methane reusable engine precursor in the thrust class 1000 kN will be ground tested in 2020 for use on future versions of the European launcher family, after Ariane 6 and Vega-C. See http://www.esa.int/spaceinimages/Images/2017/06/Prometheus