International Launch Services announced about new plans, which can cause that their modification of flagship rocket -Proton-M will be put on the shelf.
In the Autumn 2016 it seemed rather sure, that ILS will show medium sized version of Proton-M within following two years. In October 2016 Company even announced, that has first customer for Proton Medium and already signed contract. It was confirmed that first commercial flight was contracted to Eutelsat Communications and it is part of agreement signed one year ago and known as Multi-Launch Agreement (MLA). But after six months in the official announcement (from March 7, 2017) in spite of fact, that date of the first flight is closing, ILS announced surprising fact. Company decided to focus on developing larger payload fairing for Proton-M. This fact stands in the opposition to previous plans and means that resources of Khrunichev State Research and Production Space Center, manufacturer of the Proton, are objected now on something different than creating medium sized version of Proton. What is even more surprising, process of developing new fairing started in 2016, so probably shortly after announcing contract with Eutelsat. As we can read in the statement:
“Khrunichev State Research and Production Center (Khrunichev) has successfully completed their planned 2016 feasibility study which focused on developing the required technologies and design needed to support the 5 meter PLF development..."
ILS claims, that new fairing is response for market demands and will offer space for larger satellites. New fairing will be 5 m wide (4.25 m previously) and one meter longer (16.25 m). This change will surely affect on performance, but probably payload mass will change only slightly - ILS surely would like to remove one of the limitations of the Proton-M and use this heavy rocket also for satellites with unusual construction, for example with extra wide antennas. Thanks to this modification Proton-M would enter into (as far as the diameter is concerned) same league as Atlas V (5 m fairing) and Ariane 5 (maximal size 5.4 m).
Fairing will pass through various tests and it is planned, that it will enter service in 2020. It is hard to predict if Khrunichev State Research and Production Space Center will manage to keep project of Proton Medium up to schedule, when its first flight was planned for 2018. If project of fairing is planned to last at least three years, it is rather hard to believe that modification of rocket, which is more complicated process will take only two years; more probable is that we will see Proton Medium in early 2020s.