The Russian submarine was present near U.S. territorial waters from June to July 2012. According to the journal, the fact that the U.S. Navy failed to detect the submarine causes concern in U.S. force circles.

TRINDEC: Someone here recently said that any submarine is elementarly detectable from space.
Even the sonar network did not help.
Volgoman: So our military trick was applied - descended under water. If they were on the surface, the U.S. military would have detected them from space. and :)