ISS Crew To Attempt Undocking Again Tonight

ISS Crew To Attempt Undocking Again Tonight

NASA reports that the three ISS crew members who tried to return to Earth last night but could not because the Soyuz would not undock from the space station will try again tonight at 10:02 pm EDT. Following is NASA’s explanation of what happened and how they think they have solved it.

The first undocking attempt Thursday was delayed after hooks failed to open and mission controllers in Moscow had not received the expected hatch locked signal from the Poisk module [where the Soyuz is docked].

“Though leak checks between the station and the Soyuz were good, commands to open hooks between the station and the Soyuz were not received….

“Flight Engineer Fyodor Yurchikhin encountered some resistance Thursday night when closing the Poisk module hatch. He began troubleshooting the hatch when commands to open the hooks on the Poisk docking interface were not received. He discovered a loose star-shaped sprocket with two broken teeth behind the hatch cover.

“To re-initiate the “hatch locked” signal, Yurchikhin installed jumper cables to bypass a component in the docking mechanism. This allowed the hooks on Poisk to be opened overnight which will allow the Soyuz TMA-18 to undock when hooks on the Soyuz are commanded open.”

If undocking is successful, the crew will land at 1:21 am EDT tomorrow in Kazakhstan.

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