After being docked for nearly 44 hours, Apollo and Soyuz parted for the first time and were station-keeping at a range of 50 meters. The Apollo crew placed its craft between Soyuz and the sun so that the diameter of the service module formed a disk which blocked out the sun. After this experiment Apollo moved towards Soyuz for the second docking.

Three hours later Apollo and Soyuz undocked for the second and final time. The spacecraft moved to a 40 m station-keeping distance so that an ultraviolet absorption experiment could be performed. With all the joint flight activities completed, the ships went on their separate ways. References: 2, 6, 32, 33,60, 452.

After being docked for nearly 44 hours, Apollo and Soyuz parted for the first time and were station-keeping at a range of 50 meters. The Apollo crew placed its craft between Soyuz and the sun so that the diameter of the service module formed a disk which blocked out the sun. This artificial solar eclipse, as viewed from Soyuz, permitted photography of the solar corona. After this experiment Apollo moved towards Soyuz for the second docking.

Three hours later Apollo and Soyuz undocked for the second and final time. The spacecraft moved to a 40 m station-keeping distance so that the ultraviolet absorption (UVA MA-059) experiment could be performed. This was an effort to more precisely determine the quantities of atomic oxygen and atomic nitrogen existing at such altitudes. Apollo, flying out of plane around Soyuz, projected monochromatic laser-like beams of light to retro-reflectors mounted on Soyuz. On the 150-meter phase of the experiment, light from a Soyuz port led to a misalignment of the spectrometer, but on the 500-meter pass excellent data were received; on the 1,000-meter pass satisfactory results were also obtained.

With all the joint flight activities completed, the ships went on their separate ways. On 20 July the Apollo crew conducted earth observation, experiments in the multipurpose furnace (MA-010), extreme ultraviolet surveying (MA-083), crystal growth (MA-085), and helium glow (MA-088). On 21 July Soyuz 19 landed safely in Kazakhstan. Apollo continued in orbit on 22-23 July to conduct 23 independent experiments - including a doppler tracking experiment (MA-089) and geodynamics experiment (MA-128) designed to verify which of two techniques would be best suited for studying plate tectonics from earth orbit.

After donning their space suits, the crew vented the command module tunnel and jettisoned the docking module. The docking module would continue on its way until it re-entered the earth's atmosphere and burned up in August 1975. References: 2, 6, 33,60, 452.

A failure in switchology led the automatic landing sequence to be not armed at the same time the reaction control system was still active. When the Apollo hadn't begun the parachute deployment sequence by 7,000 metres altitude, Brand hit the manual switches for the apex cover and the drogues. The manual deployment of the drogue chutes caused the CM to sway, and the reaction control system thrusters worked vigorously to counteract that motion. When the crew finally armed the automatic ELS 30 seconds later, the thruster action terminated.

During that 30 seconds, the cabin was flooded with a mixture of toxic unignited propellants from the thrusters. Prior to drogue deployment, the cabin pressure relief valve had opened automatically, and in addition to drawing in fresh air it also brought in unwanted gases being expelled from the roll thrusters located about 0.6 meter from the relief valve. Brand manually deployed the main parachutes at about 2,700 meters despite the gas fumes in the cabin.

By the time of splashdown, the crew was nearly unconscious from the fumes, Stafford managed to get an oxygen mask over Brand's face. He then began to come around. When the command module was upright in the water, Stafford opened the vent valve, and with the in-rush of air the remaining fumes disappeared. The crew ended up with a two-week hospital stay in Honolulu. For Slayton, it also meant the discovery of a small lesion on his left lung and an exploratory operation that indicated it was a non-malignant tumour. Additional Details: Landing of Apollo (ASTP).