Site 250 at the Baikonur Cosmodrome, also known as UKSS (Russian: Универсальный Комплекс Стенд-Старт, lit.

'Universal Complex Stand-Start') and Bayterek (Russian: Байтерек), is a test facility and launch site which was used by the Energia rocket during the 1980s.

The site consists of a single launch pad, which doubled as a test stand, and is supported by an engineering area and a propellant storage facility.

[1] Site 250 was built in the late 1970s as the Universal Complex Stand-Start (UKSS) to support Energia development, and unlike other Soviet launch complexes it was designed to support long-duration static tests as well as launches, after Valentin Glushko blamed the failure of the N1 programme on the lack of facilities to perform static tests.

[1] The only launch to have taken place from Site 250 was the maiden flight of the Energia rocket, carrying the Polyus spacecraft, which occurred on 15 May 1987.