Proton version
Proton Proton-M (8K82M)
The modernised and final Proton: 58.2 m, 705,000 kg at lift-off, 23,000 kg to low Earth orbit and 6,300 kg to geostationary transfer orbit. It flew 116 times from 2001, almost always with the Briz-M upper stage and mostly with commercial communications satellites.
- April 7, 2001
- First launch
- 23,000 kg
- LEO capacity
- No
- Reusable
History
What changed from the Proton-K
The Proton-M lightened the lower-stage structure, increased thrust and made full use of its propellants. Its three stages still burn the hypergolic combination of dinitrogen tetroxide and unsymmetrical dimethylhydrazine. Most flights add the storable Briz-M upper stage; six launches used the Blok DM-02 instead. In a typical mission the Proton-M places the orbital unit — payload, adapter and Briz-M — on a slightly suborbital trajectory and the upper stage completes the insertion.
Successive versions
On 7 July 2007 the first Proton-M Enhanced, also called M+, flew with the DirecTV-10 satellite; it was the 326th Proton launch. The Phase III design was flight-proven in February 2009 on the dual Express AM-44 / Express MD-1 mission and became the standard International Launch Services configuration in 2010, able to lift 6,150 kg to transfer orbit; on 19 October 2011 it carried the 6,740 kg ViaSat-1.
Failures and retirement
The record stands at 116 launches with 105 successes. Among the failures, on 6 August 2012 two communications satellites were lost to a Briz-M problem, and on 2 July 2013 a Proton-M carrying three GLONASS satellites crashed beside the Baikonur pad shortly after lift-off. In January 2017 the fleet was grounded when the Voronezh Mechanical Plant was found to have substituted a cheaper metal for a heat-resistant alloy in the engines. In June 2018 Roscosmos announced production would end as Angara came online, and on 9 October 2019 Proton flew its last scheduled commercial mission with Eutelsat 5 West B and Mission Extension Vehicle-1.