Dimensions of the Command Module
The Command Module was the central hub of the Apollo. It housed the crew and all the main instruments. The crew numbered 3 and the cabin was 6.17 m3. It was 3.9 m in diameter and 3.47 m long. The mass was 5,800 kg; the structure mass was 15,567 kg and the heat shield mass 848 kg.
The RCS mass was 400 kg. The recovery equipment was 245 kg while the telemetry was 200 kg. The size of the Apollo spacecraft’s communication systems was 100 kg. The RCS thrust was 12 x 420 kN.
The RCS impulse was 257 kN-s. The RCS propellants were N2O4/UDMH.
The system batteries were electric (20.0 kWh, 1000 Ah). The module also had the side hatch, the reaction control system and the electronic guidance systems.
Dimensions of the Service Module
This contained the fuel, water, radiation batteries and other equipment. Its length was 7.56 m and had a diameter of 3.90 m. The structure mass was 1,910 kg and the electrical equipment had a mass
of 1,200 kg. The RCS specific impulse Isp was 290 s (2.84 kN s/kg).
The RCS thrust was 16 x 440 N. The SPS engine thrust was 98 kN and the SPS engine specific impulse Isp was 314 s (3.08 kN s/kg). The size of the Apollo spacecraft’s Service Module gave it an engine mass of 3,000 kg.
A large part of the Service Module was comprised of the engine. One of the engine’s main tasks was to create mid course corrections between the Moon and the Earth.
Dimensions of the Lunar Module
This was the component that landed on the Moon. In a real sense it was the first spaceship ever built. The module was divided into two parts: the Ascent and Descent Module. The Descent module had the landing gear, the fuel and engine. The Ascent had the crew cabin, radar and other equipment.
The Ascent Module cabin was 6.65 m3 and 3.5 m high. Its diameter was 4.27 m with a stage mass of 4,547 kg. The size of the Apollo spacecraft’s Descent module was 2.8 m (height). The diameter was 4.21 m. The landing gear diameter measured 9.37 m.
Dimensions of the Spacecraft Lunar Module Adapter (SLA)
Their primary function was to protect the Lunar Module. It was 8.5 m (27 ft 11 in) high with an apex diameter of 3.9 m (12 ft 10 in). The base diameter was 6.6 m (21 ft 8 n). Its weight was 1,837 kg (or 4,050 lbs). The volume was 190 m3 or 6,700 cubic ft. The SLA had 7 ft long panels fastened on the instrument unit as well.
The size of the Apollo spacecraft was designed to give it maximum mobility without compromising safety. It took the work of several scientists and engineers at NASA to make it a reality.