Analysis of the launch window was cited by observers for concluding a flight of 19 to 29 days had been planned.
[5] In the event of the failure, official TASS statements merely claimed that the mission was intended to practice docking maneuvers with the Salyut 3 station.
[4] They also said that a new automatic docking system was tested which would be used on future Progress transport craft.
[5] The failed mission exposed a number of serious design flaws in the Soyuz 7K-T spacecraft, namely its lack of reserve propellant and electrical power for repeated docking attempts.
Since it was impossible to carry out these changes before Salyut 3 finished its operating lifespan, they had to wait for future space stations.