Proton-KL

Khrunichev State Research and Production Space Center
 

In 2016, Russian space officials announced plans to develop a smaller version of the nation's venerable Proton launch vehicle. The head of Roskosmos Igor Komarov, speaking to a radio station  on June 18 said that the Proton-Light variant would be narrowly aimed at particular demands of the commercial market. According to Komarov, an extra variant would make the Proton family more effective and reduce per-kilogram cost of payload delivered into orbit.

On June 23, the head of GKNPTs Khrunichev Andrei Kalinovsky announced that the company had been preparing a new addition to the Proton family for a different type of commercial spacecraft, allowing various Proton variants to have their own individual price offers on the market.

Around the same time, various industry sources revealed the most likely architecture of the Proton-Light rocket. The key change included the removal of the second stage from the standard Proton-M rocket. Instead, the traditional third stage of the Proton-M would be "stretched" to accommodate more propellant and used as the second stage on the Proton-Light. According to some reports, the propulsion system on the second stage could be modified to re-start its engine and boost its payload from an initial parking orbit to a geostationary transfer orbit, GTO.

On Sept. 13, 2016, GKNPTs Khrunichev officially confirmed its plans to expand the Proton family and announced the coming of its additional members.
One new version of the launcher now identified as Proton-Light would be formed by the removal of two out of six strap-on tanks and their respective engines on the first stage and by the addition of an auxiliary fuel tank at the top of its main body.
The company promised to introduce that latest configuration of the vehicle in 2019, or one year after the "original" Proton-Light architecture, which was now renamed Proton-Medium.

2018, June -- Mr. Rogozin, as general director of Roskosmos, has given an order to wind-down manufacturing of "Proton" launch system, upon completion of current manifest, and retire the launcher. Angara will come as a replacement.