GLONASS-K2 satellite series
The GLONASS-K2 variant is the fourth major upgrade of the Russian navigation satellite after the original Uragan satellite and the successive modifications known as GLONASS-M and GLONASS-K.
Specifications of the GLONASS-K2 (14F160/14F170) spacecraft:
According to early plans for the modernization of the GLONASS system, the first two GLONASS-K1 modified satellites would be followed by further upgrades designated GLONASS-K2. That variant was expected to feature an unpressurized satellite bus and it would also introduce a new type of navigation signals with a so-called code-protected selection. The spacecraft would transmit three types of signals, two of which in L1 and L2 range would be designed for specialized users, such as the military, and one channel in L1 range would be available to everyone else.
Like its predecessor, the K2 variant was designed to carry equipment for monitoring nuclear tests and the emergency signal receivers for the KOSPAS search and rescue system. An unidentified military payload was also listed in the official descriptions of the K2 satellites.
Architecturally, the GLONASS-K2 series was expected to be based on the KAUR-4N platform developed at ISS Reshetnev and classified as a heavy spacecraft.
The K2 spacecraft was expected to use a new-generation thermal control system based on electrically powered thermal panels complemented with optical thermal coating, replacing traditional fluid-based systems. The new thermal control method, (first tested on GLONASS-K satellites), made it possible to maintain the temperature of some critical avionics on the spacecraft within 0.1C degrees, according to the satellite's manufacturer ISS Reshetnev. Finally, the satellite was equipped with more efficient solar panels.
GLONASS-K2 development history
As of 2010, the launch of the first GLONASS-K2 spacecraft was expected in 2013. (438) In November 2012, ISS Reshetnev announced that the completion of the preliminary design for a modified GLONASS-K satellite was now expected in October 2013.
The development of the satellite was apparently severely delayed by a ban on the supply of western electronics to Russia after the annexation of Crimea in 2014. An upgraded version of the GLONASS-K2 satellite, which was supposed to use only indigenously built components, was re-designated from 14F160 to 14F170.
The substitutions had to include not only avionics but also such elements as photovoltaic cells made of gallium arsenide, used in solar arrays, and their undercoating made of germanium.
Due to delays with the development of GLONASS-K2, Roskosmos had to expand its order of the previous-generation GLONASS-K to a total of nine satellites in order to conduct the routine replacement in orbit of older GLONASS-M satellites.
Nevertheless, in 2021, the newly approved program of the GLONASS development called for the construction of 13 additional GLONASS-K2 satellites by 2030. At the time, four K2 satellites were reported to be in production. (1017)
A photo of GLONASS-K2 satellite released in 2016 shows its testing in the GVU-600 temperature and vacuum chamber simulating conditions of space. Credit: ISS Reshetnev
A display version of the GLONASS-K2 satellite. Credit: ISS Reshetnev