Site 41 in Plesetsk for R-7-based rockets
The construction of the original launch pad in Plesetsk known as (Pad No. 1 or SK-1) was completed by the end of 1959. At the time, the R-7 ballistic missile, which was supposed to be based in Plesetsk, was still in development and, as a result, the launch hardware had to be constantly tuned up in the course of construction, to reflect changes introduced into the missile. Still, benefiting from the experience in Tyuratam, where the first test launch facility for the R-7 had been built, the first pad in Plesetsk required 800,000 tons less Earth moving and 14,000 cubic meters less concrete work.
A mosaic of satellite images showing Site 41 in Plesetsk. Credit: Google Earth
After several years in service as an operational launch site for the R-7 ballistic missile, the conversion of the SK-1 for space launches started on March 19, 1965. It included the replacement of the original launch structures with new access gantries that could provide access to upper stages which were placed on top of the R-7 missile to form the space launcher.
On December 14 of the same year, Pad No. 1 hosted the actual launch, sending an R-7 ballistic missile on a suborbital trajectory toward the Kamchatka Peninsula.
The first orbital mission originating from Plesetsk also lifted off from Pad No. 1 on March 17, 1966. Until 1968, Pad No. 1 and its personnel supported both ICBM operations and space missions.
On September 30, 1972, the first Molniya-2 satellite was launched from Pad No. 1 and from March 1973, Soyuz-U rockets were prepared for launch at the adjacent processing facility. The launch vehicle carrying the Bion satellite lifted off on October 31 of the same year.
In 1977, the SK-1 underwent renovations, with all space launches transferred to Pads 3 and 4 in the interim. Repairs were continuing as late as April 1978.
On May 15, 1982, a Soyuz-U rocket failed less than half a minute after a liftoff from Pad No. 1 and crashed apparently around 140 meters northeast from the facility.
A total of 310 launches (according to another source - 319) originated from Pad No. 1, however it was dismantled after its final launch on September 15, 1989. An official display posted in the 2020s near the headquarters of the military unit serving Site 41 listed a total of two ICBM launches and 313 space vehicles launched from SK-1.
Year-by-year statistics of launches shown on the poster were as following:
In June 2013, the official newspaper of the Russian Ministry of Defense reported that "infrastructure for testing of light and heavy Angara rockets was under development at Site 41." (654) Essentially, the processing infrastructure and personnel from Millitary Unit No. V/Ch 13973, that had originally supported launch operations at Site 41, was repurposed for ground operations of the Angara rocket familly.
Launch facilities for space vehicles based on the R-7 ballistic missile:
A launch pad for the R-7-based launch vehicles in Plesetsk.