…during the automatic approach phase [to Salyut 5, in orbit], the automatic docking system malfunctioned… The mission, accordingly, had to be abandoned.
The craft had only two days of battery power, so systems were powered off, including the radio, to conserve power. The day’s landing opportunity had already passed, so they had to wait for the next day’s landing opportunity near the Baikonur Cosmodrome.
On 16 October, Soyuz 23 returned to earth and landed 8:45 p.m. local time … on a freezing Lake Tengiz, 8 km from shore, in the middle of a blizzard, with fog and temperatures at −22 °C. The capsule was designed to land in any conditions, even in a body of water, so the only concern was the increased difficulty in finding the capsule and crew.
The parachute quickly filled with water and dragged the capsule and its crew beneath the surface; in addition an electrical short caused by the water impact caused the reserve parachute to accidentally deploy. The capsule cooled in the freezing water, and the cosmonauts removed their pressure suits and donned their normal flight suits, expecting a quick rescue. The parachutes became waterlogged and pulled the capsule onto its side, preventing the hatch from being opened. The transmission antennas were also under water, so the crew could not communicate with rescue teams.
The capsule’s beacons could not be seen in the heavy fog, and rubber rafts used to try to reach them were blocked by ice and sludge. Amphibious vehicles were airlifted to the vicinity, but could not reach the capsule owing to bogs surrounding the lake. Accordingly, the rescue was called off until dawn. The cosmonauts were safe, but they were low on power, so they were forced to shut down everything but a small interior light.
The next morning, frogmen were dropped in by helicopters and attached flotation devices to the Soyuz craft. The capsule was too heavy to be lifted by the helicopter, so it was dragged to shore. The recovery operation had taken nine hours. No attempt was made to open the hatch as the recovery crews assumed the cosmonauts were dead, so they called for a special team to remove their bodies. Eventually, eleven hours after splashdown, the cosmonauts opened the hatch and emerged alive and well, if badly chilled (the interior of the descent module was coated with frost).
via SpaceX reddit