0437 GMT May 22, 2019
"On February 12, 2019,… the first 'marketable' RD-108A liquid rocket engine of the central bloc of the Soyuz-type rocket based on new naphthyl fuel was tested," the spokesperson said.
Naphthyl fuel was first used instead of kerosene during the launch of the third stage of the Soyuz-2 rocket from Vostochny Cosmodrome in November 2017. Tests for the engines of the first and the second stages of the carrier rocket have not been carried out before. The first launch of a Soyuz-2 with all engines using naphtyl is scheduled for 2019.
First and second stages of the Soyuz-type rockets have being equipped with RD-107 and RD-108 engines since 1958. These engines are produced by JSC Kuznetsov, the largest enterprise of aviation and space propulsion engineering that is part of the United Engine Corporation.
The transition to naphthyl from kerosene is carried out as part of the modernization of the Soyuz-2 rocket for launches from Vostochny Cosmodrome.