Iran successfully launched its heaviest space payload on Friday, comprising a satellite and a space tug, using a satellite carrier developed by the country, official media reported. The 300-kilogram (660-pound) payload consisted of the Fakhr-1 telecommunications satellite and the Saman-1 space tug, according to state television.

Saman-1 is an “orbital transfer system” designed to move satellites from low orbits to higher orbits, as the Iranian Space Research Center announced when it was unveiled in 2017. According to the TV report, the launch marks an “operational step” to move satellites into higher orbits. The system was first introduced in February 2017 at a ceremony attended by then-Iranian President Hassan Rouhani, and a test launch was planned for 2022.

The payloads were launched from the Imam Khomeini Launch Base in Semnan province using the indigenous Simorgh satellite carrier. Named after a legendary Persian bird, Simorgh is a two-stage, liquid-fueled launch vehicle developed by the Iranian Ministry of Defense.

In September, Iran announced that it had successfully launched the Chamran-1 research satellite into orbit using the Ghaem-100 launch vehicle produced by the aviation division of the Kingdom’s Revolutionary Guard. Western governments, including the United States, have repeatedly warned Iran against such launches, arguing that the technology used for satellites could potentially be applied to ballistic missiles capable of carrying nuclear warheads.

Iran denies seeking nuclear weapons. He has consistently stated that satellite and missile launches are focused on civilian and defense purposes. Last month, Russia launched 55 satellites, including Kosvar and Khokhod, built by Iran; this was a reflection of the deepening political, economic and military ties between the two countries.