Figure 1-10. Proton configured for
L1 (Zond).
Note the modified Soyuz
shroud (top).
Launch weight (Zond 4 through 6) ............ 5140 kg
Launch weight (Zond 7, 8) ....................... 5390 kg
Launch vehicle ....................................... Proton (four-stage); N-1
Length at launch .................................... 5.0 m
Length after support cone ejection ........... 4.5 m
Span across solar arrays ........................ 9 m
Diameter of habitable module .................. 2.2 m
Maximum diameter ................................ 2.72 m
Habitable volume ................................... 3.5 m3
Number of crew ..................................... 1-2*
*Never carried a crew.
1.4.2 L1 Notable Features
Typically launched atop a fourstage Proton rocket (figure 1-10). The first three stages burn N2O4 and UDMH propellants. The Block D fourth stage, with its restartable motor, was originally intended for use with the N-1 rocket as part of the manned lunar landing program. It burns kerosene and liquid oxygen. It would have inserted the L2 and L3 into lunar orbit and provided most of the DV for powered descent of the L3 to the lunar surface. The L1 used it for translunar injection.
Launched under a modified Soyuz launch shroud.
Launch escape system’s solid rocket motors smaller than those on the Soyuz shroud, in keeping with the lower mass it was designed to drag to safety.
Had an inverted cone-shaped support structure around the hatch at the top of the descent module
to attach it to the Soyuz launch shroud, and through that to the
escape system. This was ejected in Earth parking orbit or after translunar injection.
Lacked an orbital module.
Lacked docking systems.
Lacked the toroidal instrument container located in aft skirt of Original Soyuz.
Lacked intermodule umbilical linking the service module to the orbital module.
Had no backup main engine in the version flown. The sole engine was based on the Soyuz KDU-35 system. Propellant mass was only
400 kg.
Had shorter solar arrays than Soyuz.
Had an ablative heat shield thicker than that on the Original Soyuz to withstand atmospheric friction heating at lunar reentry velocities.
Carried an umbrella-like highgain antenna on its descent module.
