Secret Soviet Space Losses

According to:

http://fallbackbelmont.blogspot.com/...agle-flew.html

"As 40 years have passed since Gagarin's flight, new sensational
details of this event were disclosed: Gagarin was not the first man
to fly to space. Three Soviet pilots died in attempts to conquer
space before Gagarin's famous space flight, Mikhail Rudenko,
senior engineer-experimenter with Experimental Design Office
456 (located in Khimki, in the Moscow region) said on Thursday.
According to Rudenko, spacecraft with pilots Ledovskikh, Shaborin
and Mitkov at the controls were launched from the Kapustin Yar
cosmodrome (in the Astrakhan region) in 1957, 1958 and 1959.
"All three pilots died during the flights, and their names were never
officially published," Rudenko said."


Since the fall of the USSR, how many other Soviet space
disasters have come to light?