Soyuz MS-14 approach
The Soyuz MS-14 spacecraft approaches the ISS Aug. 26 on its second attempt to dock with the station. The Soyuz MS-13 spacecraft, which moved a day earlier to free up a docking port for Soyuz MS-14, is in the foreground. Credit: NASA TV

WASHINGTON — An uncrewed Soyuz spacecraft successfully docked with the International Space Station Aug. 26, nearly 72 hours after aborting its original attempt to dock with the station.

The Soyuz MS-14 spacecraft docked with the aft port on the Zvezda service module at 11:08 p.m. Eastern. Flight controllers reported no issues with the automated docking of the spacecraft on a rare uncrewed test flight.

The Soyuz, launched Aug. 21 from the Baikonur Cosmodrome, was originally scheduled to dock with the Poisk module early Aug. 24. However, cosmonauts on the station issued commands to the Soyuz to abort the attempted docking because of problems with the Kurs automated rendezvous system on the station.

The Russian state space corporation Roscosmos originally announced that cosmonauts would replace the Kurs unit in Poisk and attempt another docking about 48 hours later. Instead, Russian officials decided to move the Soyuz MS-13 spacecraft, which originally docked with the Zvezda module, to Poisk, freeing up the Zvezda port for Soyuz MS-14.

Alexander Skvortsov, Andrew Morgan and Luca Parmitano boarded Soyuz MS-13 on the evening of Aug. 25, undocking from Zvezda at 11:35 p.m. Eastern and docking with Poisk 24 minutes later. The “relocation” maneuver was the first for a Soyuz spacecraft since August 2015, when the Soyuz TMA-16M moved from Poisk to Zvezda.

Russia launched Soyuz MS-14 without a crew as a test of using the newer Soyuz-2.1a launch vehicle for future crewed Soyuz spacecraft, replacing the Soyuz-FG vehicle currently used for such missions. The Soyuz is carrying about 650 kilograms of cargo, including a humanoid robot known as FEDOR or Skybot F-850. Cosmonauts will test the robot on the station before returning it to Earth when Soyuz MS-14 undocks Sept. 7.

The successful Soyuz docking clears the way for the Aug. 27 departure of a Dragon cargo spacecraft berthed to the station for the last month. The Dragon, launched July 25 on the CRS-18 cargo mission, will be released from the station’s robotic arm at 10:42 a.m. Eastern and reenter several hours later, splashing down in the Pacific Ocean 500 kilometers southwest of Long Beach, California, at 4:21 p.m. Eastern. The Dragon will return a number of experiments performed on the station and other cargo with a total mass of more than 1,200 kilograms.

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...