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Kontakt (figure 1-15). The docking system was to be used only once during the mission, after the L3 had completed its lunar landing mission and returned to orbit. Little docking accuracy was required to link the spacecraft firmly enough to let the moonwalking cosmonaut return to the L2 by EVA. Made no provision for internal crew transfer after docking. Orbital module had an EVA hatch larger than the one on the Original Soyuz. Electronics more complex than those on the Original Soyuz, in keeping with its more demanding mission.		Oxygen/hydrogen fuel cells and batteries replaced the solar arrays of the Original Soyuz. Descent module had a heat shield thicker than that of the Original Soyuz, permitting it to withstand reentry at lunar return speeds.
		Figure 1-15. Kontakt docking system. Never used in space, the system was designed for the Soviet lunar program. The Aktiv unit (top) was located at the front of the L2, while the passive unit was located on top of the L3 lander.

1.5.3 L2 Mission Descriptions

None of the planned L2 missions reached orbit.

	Launch failure	June 27, 1971
	The launch shroud of the third N-1 to be launched (number 61) covered L2 and L3 test articles, and was topped by a dummy launch escape system. Immediately after liftoff, eddies developed in the exhaust streams of the 30 NK-15 engines in the N-1 first stage; this, coupled with roll control and aerodynamic inadequacies, allowed the rocket to roll about its long axis. At 48 sec, the rocket began to disintegrate under the torque generated by the roll. The top part of the N-1, including the test articles, fell off. It crashed near the N-1 launch pad, while the lower part of the rocket flew on. At 51 sec, the engine control system automatically shut down the first stage engines. The lower stages impacted 20 km downrange and exploded, gouging a crater 30 m wide.

	Launch failure	November 23, 1972
	The launch shroud of the fourth N-1 to fly (number 71) contained an L3 mockup and a prototype L2. Ninety sec into the flight, the six central engines in the first stage shut down as planned. At 104 sec, lines leading into the deactivated engines burst under pressure from backed-up kerosene fuel. Kerosene spilled on the still-hot engines. The last N-1 to fly exploded 107-110 sec after liftoff, just 40 sec before planned first-stage separation. Another account traces this failure to a foreign object in the number 4 engine oxidizer pump, making it a near-replay of the failure which destroyed N-1 number 51 in July 1969. The launch escape system plucked the descent and orbit modules of the L2 free of the N-1. This L2 was the last Soyuz variant to launch on a rocket other than the Soyuz launcher.