Advanced control system, which formed the basis for the later Neptune control system of Soyuz T.

Longer (10 cm) descend module with strengthened heatshield.

Larger propulsion system (called Block I).

Orbital module with attitude control jets.

Differed from other soyuz craft by many details. Lunar command module for the Russian lunar landing program. Had no internal transfer tunnel, so crew transfer had to happen making a EVA. The first Soyuz generation, designed for docking test mission. Its propulsion section was later included in the Almaz 1 station, as the prefered Almaz project was about to miss its deadline. Military spacestation, similar to the MOL. Military version equipped with unguided rockets for attacking other spacecraft

Ejectable electronics compartment at the aft of the spacecraft, which contained the rendezvous guidance system.

Cylindrical orbital module, instead of the later spherical ones.

There are also some differences to the later built soyuz spacecraft:

Automatic rendezvous and docking system.

The Soyuz A already had almost all typical design features of the later soyuz craft: Its mission consisted actually of three different spacecraft: Soyuz A as crew module, Soyuz B as eject stage and Soyuz C as tanker. Initial Soyuz concept for a lunar fly by spacecraft. The two radiators provide thermal control for the whole spacecraft until separation. Most Soyuz variants rely on solar arrays as power supply, but for a long time, it was also common to use only batteries, which limited the independent flight time to about two days.Д«ehind the solar arrays is a large radiator which wrap around the whole module. The electronics section contains the electronics used for docking and rendezvous, as well as the heat exchangers for the thermal control subsystem and the power supply systems. The propulsion module consists of a intermediate section at the front, a pressurized electronics section and the unpressurized assembly section with the propulsion system, the electrical subsystem and parts of the life support system.Дirectly behind the heatshield of the DM is the intermediate section, also known as transfer section, which contains the supports for the heatshield, most of the RCS thrusters and the smaller radiator of the thermal control system. The Descent Module contains the three crew couches that are used for launch and reentry, and storage cabinets under the couches for their spacesuits. This is neccessary as the descend module is simply to small to allow more than three hatches.

The internal transfer hatch through the docking port (not installed in all soyuz crafts)Д¬rew ingress takes place by the crew entering first the orbital module and then climb into the descend module.

This is the only way of entering the spacecraft at launch, The orbital module contains the docking port, storage for food and water for the crew, storage for EVA space suits and a few spacecraft controls (mostly for light and communications initially). Generally all soyuz spacecraft consist of:

Orbiter addons soyuz