Launch from Cape Canaveral and landing in the Pacific Ocean near Hawaii. It was the first U.S.-U.S.S.R joint manned mission Apollo-Soyuz.

The Command Module (CM) was a conical pressure vessel with a maximum diameter of 3.9 m at its base and a height of 3.65 m. It was made of an aluminum honeycomb sandwich bonded between sheet aluminum alloy. The base of the CM consisted of a heat shield made of brazed stainless steel honeycomb filled with a phenolic epoxy resin as an ablative material and varied in thickness from 1.8 to 6.9 cm. At the tip of the cone was a hatch and docking assembly designed to mate with the lunar module. The CM was divided into three compartments. The forward compartment in the nose of the cone held the three 25.4 m diameter main parachutes, two 5 m drogue parachutes, and pilot mortar chutes for Earth landing. The aft compartment was situated around the base of the CM and contained propellant tanks, reaction control engines, wiring, and plumbing. The crew compartment comprised most of the volume of the CM, approximately 6.17 cubic meters of space. Three astronaut couches were lined up facing forward in the center of the compartment. A large access hatch was situated above the center couch. A short access tunnel led to the docking hatch in the CM nose. The crew compartment held the controls, displays, navigation equipment and other systems used by the astronauts. The CM had five windows: one in the access hatch, one next to each astronaut in the two outer seats, and two forward-facing rendezvous windows. Five silver/zinc-oxide batteries provided power after the CM and SM detached, three for re-entry and after landing and two for vehicle separation and parachute deployment. The CM had twelve 420 N nitrogen tetroxide/hydrazine reaction control thrusters. The CM provided the re-entry capability at the end of the mission after separation from the Service Module.
The Service Module (SM) was a cylinder 3.9 meters in diameter and 7.6 m long which was attached to the back of the CM. The outer skin of the SM was formed of 2.5 cm thick aluminum honeycomb panels. The interior was divided by milled aluminum radial beams into six sections around a central cylinder. At the back of the SM mounted in the central cylinder was a gimbal mounted re-startable hypergolic liquid propellant 91,000 N engine and cone shaped engine nozzle. Attitude control was provided by four identical banks of four 450 N reaction control thrusters each spaced 90 degrees apart around the forward part of the SM. The six sections of the SM held three 31-cell hydrogen oxygen fuel cells which provided 28 volts, two cryogenic oxygen and two cryogenic hydrogen tanks, four tanks for the main propulsion engine, two for fuel and two for oxidizer, and the subsystems the main propulsion unit. Two helium tanks were mounted in the central cylinder. Electrical power system radiators were at the top of the cylinder and environmental control radiator panels spaced around the bottom.

Jack Swigert had originally been assigned as the command module pilot for the ASTP prime crew, but prior to the official announcement he was removed as punishment for his involvement in the Apollo 15 postage stamp scandal.

This mission was the first joint U.S.–Soviet space flight, and the last flight of an Apollo spacecraft. Its primary purpose was as a symbol of the policy of détente that the two superpowers were pursuing at the time, and marked the end of the Space Race between them that began in 1957.

The Soyuz and Apollo flights launched within seven-and-a-half hours.
The Apollo Command & Service Module (CSM) was launched with a docking module specially designed to enable the two spacecraft to dock with each other, used only once for this mission. The docking module was designed as both an airlock - as the Apollo was pressurized at 5.0 psi using pure oxygen, while the Soyuz used a nitrogen/oxygen atmosphere at sea level pressure - and an adapter, since the surplus Apollo hardware used for the ASTP mission was not equipped with the APAS docking collar jointly developed by NASA and the Soviet Academy of Sciences for the mission. One end of the docking module was attached to the Apollo using the same "probe-and-drogue" docking mechanism used on the Lunar Module and the Skylab space station, while its other end had the APAS docking collar, which Soyuz 19 carried in place of the standard Soyuz/Salyut system of the time. The APAS fitting with the Soyuz 19 was releasable, allowing the two spacecraft to separate.

The Apollo spacecraft docked with Soyuz 19. The docking adapter had been carried through Apollo. It was the first docking in space history between two spacecraft launched from different countries. 44 hours of docked joint activities which included 4 crew transfers between the Apollo and the Soyuz followed. The mission included both joint and separate scientific experiments (including an engineered eclipse of the Sun by Apollo to allow Soyuz to take photographs of the solar corona), and provided useful engineering experience for future joint US–Russian space flights.

After separation of the spacecrafts a second docking with Soyuz 19 as the active spacecraft was done, but no more crew transfers. After the final separating the Apollo crew accomplished 23 different scientific experiments, as earth observation, experiments in the multipurpose furnace (MA-010), extreme ultraviolet surveying (MA-083), crystal growth (MA-085), a helium glow experiment (MA-088), a doppler tracking experiment (MA-089) and geodynamics experiment (MA-128).

The only serious problem was during reentry and splashdown of the Apollo craft, during which the crew were accidentally exposed to toxic nitrogen tetroxide fumes, caused by the reaction control system (RCS) oxidizer) venting from the spacecraft and reentering a cabin air intake. The RCS was inadvertently left on during descent, and highly toxic nitrogen tetroxide was sucked into the spacecraft as it drew in outside air. Vance Brand briefly lost consciousness, while Thomas Stafford retrieved emergency oxygen masks, put one on Vance Brand, and gave one to Donald Slayton. The three astronauts were hospitalized for two weeks in Honolulu.

The recovery ship was the USS New Orleans. This was the last NASA mission for several years. The Apollo program ended.