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1.6.2 L3 Notable Features

  • Not a Soyuz derivative per se, though it was developed as part of the same program which produced the Soyuz-derived L1 and L2 vehicles. L3 was to have been used with the L2 vehicle.
  • Flight-test version of the L3 was called T2K. It was launched for Earth-orbital tests on a modified Soyuz rocket with an enlarged (“large caliber”) launch shroud.[1] T2K had its landing legs replaced by two units for returning systems telemetry to Earth.
  • For lunar landing missions, was to be launched on a three-stage N-1 rocket, within a shroud, as part of the LRS. The LRS consisted of Block D and Block G rocket stages, the L3 lunar lander, and the L2 command ship.
  • The Block D stage carried out midcourse corrections en route to the Moon and braked the L2 and L3 into lunar orbit. After lunar orbit insertion, a single cosmonaut exited the L2 through the hatch in its living module, traversed the length of the L2 with the aid of a mechanical arm, and entered the L3 through a port in the shroud enclosing it. The shroud then fell away as the Block D and L3 separated from the L2.
  • Restartable rocket motor on the Block D provided most of the DV for powered descent to the lunar surface. The Block D was to be depleted and discarded about 1 to 3 km above the surface. After it was discarded, the Block D crashed on the lunar surface a short distance from the L3 touchdown point.
  • ?Had one single-nozzle main engine on its longitudinal axis, one two-nozzle backup engine, and four verniers. The lozenge-shaped propulsion unit was dubbed the Ye unit. Loaded with
N2O4 and UDMH propellants, the Ye unit weighed approximately 2250 kg (half the weight of the L3). N2O4 was stored in a toroidal tank surrounding the engine units. This fuel load gave the L3 about 1 min of flight time before it began to cut into its ascent reserves.
  • Control system was the first in the Soviet program based on an onboard computer. Inputs were derived from a three-axis gyrostabilized platform, landing radar, and a collimating sight. The cosmonaut would use the sight to spot the selected landing site, then input the coordinates to the computer. Computer commands were verified using Sun and planet sensors.
  • Two 40-kg thrusters gave pitch control; two more gave yaw
control; and four 10-kg thrusters gave roll control. The system was exactly duplicated on a separate control circuit to provide redundancy.[2]
  • Lone cosmonaut stood before a large, round, downward-angled window; controlled flight manually using a control panel located to the right of the window and control sticks. A smaller window faced upward to provide visibility during docking.
  • Cabin atmosphere was oxygen/nitrogen at 560 mm/Hg, with slightly less nitrogen than the terrestrial mix normally used in Soviet spacecraft.[3]
  • Relied on five chemical batteries for its electricity. Two were located on the ascent portion of
Figure 1-17. L3 ascent.
  1. Filin, p. 18.
  2. Filin, p. 21.
  3. Filin, p. 20.