• the laser-based Kontakt rendezvous and docking system had to either be backed up with redundancy throughout, or an independent back-up system had to be developed
• the L3 had to be designed with an internal transfer compartment, as was being done for the DOS/7K-T space station system
• each stage of the N1 had to undergo flammability tests
• the mission scenario had to be reformulated to provide support by more than one cosmonaut on the moon at a time, and use of automated landers and rovers from Babakin at Lavochkin
• landings of the capsule in the equatorial oceans of the world had to be eliminated. The capsules had to land on the territory of the USSR

At 05:20 the State Commission and their guests arrive at the Area 95 observation point to view the launch. The booster takes off on schedule at 06:40 in light rain and 60 km/hr wind. The tracking station reports good orbital insertion, separation from the third stage, and antennae and solar panel deployment. But the cover of the scientific equipment bay does not separate. This will mean that many experiments cannot be accomplished. It is decided to launch the crew to the station anyway, since the station is otherwise functioning normally. The cosmonauts go to the baths in the evening. Additional Details: Salyut 1. References: 2, 6, 67, 274, 376.

PVO radars pick up the capsule as it soars over the Caspian Sea, and a Mi-4 helicopter sights the parachute even before it thumps down, upright, on the steppes. During the landing, the Soyuz air supply became toxic, and Rukavishnikov was overcome and became unconscious. Nevertheless the crew safely landed at 23:40 GMT, 120 km NW of Karaganda. At the cosmodrome, Chertok is assigned to head a special commission to find the cause of the docking failure and correct it before the next mission can be launched. The VVS aircraft leaves at 07:00 for Moscow. Mishin was to accompany the VPK on their aircraft back, but he is drunk and has to go separately at 15:00. The Soyuz 10 crew reaches Chkalovsky Air Base at 14:00 on 26 April and proceed to Star City for further debriefings. Film and photos indicated that the docking system on the Salyut was not damaged, setting the stage for the Soyuz 11 mission. References: 367, 376.

President Nixon had nominated Fletcher for the position on March 1, and the Senate had confirmed the nomination on March 11. George M. Low, NASA Deputy Administrator, had been Acting Administrator since the resignation of Paine on September 15, 1970. References: 16.

Imaging of the surface of Mars by Mariner 9 was delayed by a dust storm which started on 22 September 1971 in the Noachis region. The storm quickly grew into one of the largest global storms ever observed on Mars. By the time the spacecraft arrived at Mars no surface details could be seen except the summits of Olympus Mons and the three Tharsis volcanoes. The storm abated through November and December and normal mapping operations began. The spacecraft gathered data on the atmospheric composition, density, pressure, and temperature and also the surface composition, temperature, gravity, and topography of Mars. A total of 54 billion bits of scientific data were returned, including 7329 images covering the entire planet. After depleting its supply of attitude control gas, the spacecraft was turned off on 27 October 1972. Mariner 9 was left in an orbit which should not decay for at least 50 years, after which the spacecraft will enter the Martian atmosphere.

The Mariner 9 mission resulted in a global mapping of the surface of Mars, including the first detailed views of the martian volcanoes, Valles Marineris, the polar caps, and the satellites Phobos and Deimos. It also provided information on global dust storms, the gravity field as well as evidence for surface aeolian activity. References: 2, 6, 278, 296.

Equipment aboard Salyut 1 included a telescope, spectrometer, electrophotometer, and television. The crew checked improved on-board spacecraft systems in different conditions of flight and conducted medico-biological research. The main instrument, a large solar telescope, was inoperative because its cover failed to jettison. A small fire and difficult working conditions will lead to a decision to return crew before planned full duration of 30 days. References: 2, 6, 32, 33, 60, 376.

As Kamanin is on the way to the airport, a serious situation develops aboard the station. At 13:00 the cosmonauts report a strong burning smell, and smoke in the station. The crew evacuates the station and retreat to the Soyuz lifeboat. Forty minutes later, just as Kamanin is boarding the Tu-104, Shatalov reports that the mission will continue, but the situation aboard the station is not comfortable. The crew has turned off the primary oxygen regenerator and exchanged the filters of the oxygen supply and reserve regenerator. At 14:05 Kamanin finally boards the aircraft, which takes off and sets course for the Crimea. At 14:30 they are ordered to turn around and land at Chkalovksy Airfield outside Moscow. The whole thing turns out to be a banal mistake by one of the officers at an air traffic control station! They lose two hours in the process. No information is available when the Tu-104 finally lands at Saki, since Nikolayev and the other cosmonauts who attended the emergency meetings had taken off to return to Moscow three hours earlier. Kamanin finally arrives at Yevpatoriya at 23:00, in time for a comms session with Dobrovolsky and Patsayev (Volkov is sleeping). The Soyuz 11 crew reports that the training suits are very tiring. Dobrovolsky reports all is now normal otherwise. He requests permission to continue the flight. Bykovsky reports that the situation on the station is now stable. There is no more smoke or burning smell, but the crew has been overloaded in the last six hours. They have done a lot of work with no food or rest. The situation was so bad at one point that preparations had been made for undocking the Soyuz for an emergency return to earth. References: 376.

The bigwigs arrive from Moscow to be in on the landing. But Afanasyev, Keldysh, Mishin, and Karas all remain at the cosmodrome for the investigation into the N1 failure. References: 376.

After the crew has left the station, taken their seats in the capsule, and closed the hatch between the Soyuz BO orbital module and SA re-entry capsule, the strained voice of Volkov comes from space: 'Hatch not hermetically sealed? What's happening? What's going on?'. All this response to the fact that the caution and warning panel 'Hatch open' light has not gone out. Yeliseyev calmly advises the crew, 'Don't panic. Open the hatch, and move the wheel to the left to open. Close the hatch, and then move the wheel to the right six turns with full force'. The crew does this several times, but the light still won't go out. On a final attempt, with 6.5 turns of the wheel, the light goes out. On the second half of he 15th orbit, the crew lowers the pressure in the BO to 160 mm, and the hatch proves to be air-tight.

On the 16th orbit the crew separates their Soyuz from the Salyut station. At 21:35 they report normal separation and that they 'can see how the station moves away from the spacecraft'. They have enough propellant to stop the separation velocity, and take photographs of the station from 10 to 15 m away. They then back away to 30-40 m, and Patsayev takes another set of photographs documenting the condition of the station. References: 376.

Telemetry shows the Soyuz braking engine begins firing at 01:35:24 and makes a nominal 187 second retrofire burn. Ground control waits for verbal confirmation, but there are no voice communications received from the capsule. At 01:47:28 the crew should have reported successful BO and PAO module separations from the capsule, but still nothing heard. It is not clear to ground control at this point - is Soyuz 11 heading for a landing or staying in orbit? From 01:49:37 to 2:04:07 the capsule is in communications range but there is no reply to the ground's calls. It is now obvious that something is wrong aboard Soyuz 11, but it is not clear what.

At 01:54 the VVS command point reports that radar has picked up the spacecraft at 2200 km uprange from the landing zone. It is on course, so the feeling is that the capsule's communications system has simply failed. The parachute deploy signal is received from within the landing zone, but still no transmissions from the crew as on earlier missions. At 02:05 an Il-14 search plane and Mi-8 helicopter spot Soyuz 11 descending under its parachute, within 200 km east of Dzhezkazgan. Soyuz 11 lands at 02:18 Moscow time. Four helicopters land simultaneously as the capsule thumps down on the steppe. The report from the recovery forces to the control centre is only one word: "Wait". There are no further tramsmissions from the recovery forces. It is clear the crew must be dead. Kamanin calls Goreglyad and tells him to set up a State Commission.

Later it is learned that two minutes after landing the hatch was opened by the recovery group and the crew was seen to be without signs of life. At 06:00 by orders of Ustinov and Smirnov the designated members of the State Commission depart from the Crimea for the landing site aboard a Tu-104, then transfer to an An-10. But on arrival they find that Goreglyad has already left for Moscow with the corpses of the crew. At 16:00 the engineers and doctors meet with the State Commission. The spacecraft's cabin, seats, parachute, equipment, and instruments have been examined. They indicate no problems - the spacecraft made a good soft landing. A hard landing was not a factor. All switches on the instrument panel were in their correct positions. A vent in one of two air valves was open 10 mm. There were no other discrepancies, even though the doctors already report that they believe the crew died from decompression of the cabin. At 23:00 the State Commission members leave for Moscow. Additional Details: Landing of Soyuz 11 and death of crew.. References: 367, 376.