Success! Progress Spacecraft Overcomes Stuck Antenna, Arrives at Station

A software fix solved a sticky antenna problem on an unmanned cargo ship, a problem that threatened to interfere with the approach and docking to the International Space Station Friday.

Progress 51 successfully docked with the massive orbiting complex at 8:35 a.m. EDT (12:35 p.m. GMT) Friday without the need of assistance from the station crew, which was standing by to take over the docking just in case.

“Progress is safely docked! Big moment for the crew. Hooray!” wrote astronaut Chris Hadfield, the commander of Expedition 35, on Twitter moments after the spacecraft and station docked.

Watch all the action in the video, below:

Crew members are expected to start unloading the three tons of food, fuel, supplies and experiment on board later today (Friday), if all goes according to schedule.

The Russian supply ship has five antennas on board that are used for approaching the station for a docking using the KURS automated system. One of them refused to unfurl as usual after the spacecraft launched from the Baikonur Cosmodrome in Kazakhstan on Wednesday (April 24).

As a backup, crew members could bring the spacecraft in using a manual system that also allows them to view the station from a camera inside Progress.

The International Space Station as seen through the eyes of Progress 51. Credit: NASA TV (screencap)
The International Space Station as seen through the eyes of Progress 51. Credit: NASA TV (screencap)

This particular antenna, NASA said, is normally used to help keep the vehicle properly oriented as it gets closer to the station.

When the Progress spacecraft and station are 65 feet (20 meters) apart, the antenna also provides data on the relative roll of the vehicle with respect to the station.

NASA initially told the crew it was expected to bring the spacecraft in manually. Shortly after 6 a.m. EDT (10 a.m. GMT), however, capsule communicator David Saint-Jacques radioed that NASA was confident a software patch created by Russian ground controllers would address the problem.

Progress 51’s final approach proceeded normally, but controllers took it a little slower than usual to ensure the automated system was working properly with the  fix. The approach started slightly early, allowing capture to occur at 8:25 a.m. EDT (12:25 p.m. GMT) — two minutes earlier than planned.

Ground control and the Expedition 35 crew then spent several minutes verifying that the antenna would not interfere with the docking port. With crew members saying they couldn’t hear any funny noises from inside the station, NASA went forward with the hard docking.

Follow updates from Expedition 35 at Universe Today, and live on NASA’s television channel online.