Falcon Heavy is an (NSSL) National Security Space Launch-certified Heavy-lift launch vehicle capable of delivering up to 63,800 kg (140,700 lb) to Low Earth orbit (LEO) or 26,700 kg (58,900 lb) to Geosynchronous transfer orbit (GTO). It uses three slightly modified Falcon 9 first stage cores with a total of 27 Merlin 1D engines.[6][7]