Russia’s un-piloted Progress 51 supply capsule managed an automated docking with the International Space Station early Friday, overcoming potential difficulties with a disabled navigation antenna.
The ISS as seen from Progress 51 cameras prior to docking. Photo Credit: NASA TV
The capsule, with just over three tons of propellant, food, water, research gear, spare parts and other supplies, carried out the first phase of an automated linkup with the station’s Russian segment Zvezda module at 8:25 a.m., EDT, following a cautious, slower than usual approach. The second phase "hard dock" that established an air tight seal followed at 8:34 a.m., after Russian controllers determined the balky antenna would not create an obstruction.
“We have capture,” announced Brandi Dean, spokeswoman for NASA’s Mission Control, where the operation was monitored.
The freighter launched April 24 from the Baikonur Cosmodrome in Russia. One of five KURS automated docking system antennas on the forward portion of the spacecraft failed to deploy after it settled into orbit. Russian flight controllers used a software patch to mask the ASF-2 antenna’s normal function of providing orientation and roll rate data along the final 20 meters of the approach along the docking corridor.
Pre-launch image shows subsequently balky antenna on Progress capsule. Image Credit: NASA TV
Efforts by Russian controllers to jar or free the antenna from its launch latch mechanism with thruster firings and exposure to alternating periods of sunlight and darkness during the transit were unsuccessful.
The suburban-Moscow control center initiated standard automated docking activities of the capsule on Friday at 6:02 a.m., EDT. At the same time, ISS cosmonauts Pavel Vinogradov and Roman Romanenko prepared the TORU, a backup manual control system that enables the pilots to command the capsule’s approach from a Zvezda control panel using video of the docking target transmitted by the Progress.
Progress 51 is scheduled to remain docked until June 11, functioning as a propulsion source for ISS altitude adjust and debris avoidance maneuvers. The European Space Agency’s un-piloted Automated Transfer Vehicle-4, Albert Einstein, is expected to dock at the same port four days after the departure.