Spaceflight Now: Space Station/STS-98

Russian cargo ship redocks to international space station
BY WILLIAM HARWOOD
SPACEFLIGHT NOW

Posted: December 26, 2000

  ISS
A video camera on the Progress M1-4 spacecraft shows the international space station during the final phase of today's rendezvous. Photo: NASA TV/Spaceflight Now
 
Cosmonaut Yuri Gidzenko remotely piloted an unmanned Progress supply ship to a trouble-free manual redocking with the international space station today as the two spacecraft sailed 230 miles above Mongolia.

The Progress M1-4 vehicle's recently upgraded automatic guidance system successfully brought the vehicle to a point just under 200 meters from the station about a half hour before the planned docking.

Then, at 5:54 a.m. EST (1054 GMT), Gidzenko, using a video monitor and a joystick hand controller in the Zvezda command module, switched to manual mode as planned and began the craft's final approach to an Earth-facing port on the station's Zarya module.

"Control system is fine Yuri?" Russian ground controllers asked.

"Yes, it is fine," Gidzenko replied.

"Are you trying to center it?"

"Yes, that's what I'm trying to do, and i'm damping the angular velocity."

"Copy."

"And I can see through the window that the movement is steady and very smooth," flight engineer Sergei Krikalev reported.

A few moments later, a target on Zarya's nadir port came into view and Gidzenko reported: "I can see the target... I see the cross on the target, so everything is fine."

"What about the range?"

"It's about 30 meters."

  ISS
The live video from Progress remained extraordinarily clear during today's redocking. Photo: NASA TV/Spaceflight Now
 
Television views from the Progress - the same scenes Gidzenko was using to remotely fly the craft as if he was on board - were carried live on NASA television.

Unlike the blurry video downlinked during the vehicle's initial docking attempt on Nov. 18, the black-and-white picture was crystal clear today, showing the station in stark detail as the Progress approached."

"We have capture and alignment," a station crew member reported at 6:03 a.m. (1103 GMT).

"A perfect docking by Yuri Gidzenko, manually bringing the Progress back to the Zarya nadir docking port for the second time," NASA mission control commentator Rob Navias reported from Houston.

"Good work, guys," Russian flight control called an hour later.

"Thank you," Krikalev replied. "The automatic mode worked quite well."

Shortly after the redocking was complete, NASA television carried a replay of video downlinked from the station earlier showing condensation build ups on internal station components.

  Water
The Expedition One crew downlinked video showing large amounts of moisture on the station's air conditioning hardware. Photo: NASA TV/Spaceflight Now
 
While the station's air conditioning system is working, large amounts of water could be seen pooling around various components in the condensate recovery system. It's not yet known whether this is a problem or not, but the sheer volume of water seen in the downlinked video was surprising.

The Progress M1-4 cargo craft was launched from the Baikonur Cosmodrome in Kazakhstan Nov. 16 and docked with the Zarya module's Earth-facing, or nadir, port two days later. The Progress was unloaded and undocked Dec. 1 to make way for arrival of the space shuttle Endeavour the next day.

During the cargo ship's initial approach Nov. 18, its KURS automatic guidance system malfunctioned and Gidzenko was forced to take over manual control using the so-called TORU system to remotely guide the craft to a safe docking.

Russian engineers traced the KURS problem to a glitch in the computer control software that prevented the ship's computer system from smoothly switching from guidance data transmitted by antennas on the Zvezda module to signals transmitted from Zarya.

A software patch was uplinked to the Progress earlier this month to correct that problem. Testing that patch to make sure future Progress vehicles can safely dock with the station was the primary objective of today's redocking.

Station
An artist's concept of the international space station with the Progress cargo ship redocked to the bottom of the Zarya module. Photo: NASA SEE THE FULL SCREEN VERSION
 
But the KURS system could only bring the Progress M1-4 vehicle to a point 200 meters or so from the station. A KURS antenna needed for the final push to docking was retracted during the initial approach and it was not designed to be re-extended.

As a result, Gidzenko once again had to take over manual control using the TORU system in the Zvezda module.

The TORU system has no backup and NASA managers initially opposed the redocking. But Russian engineers demonstrated at least three abort modes, any one of which would prevent any chance of a collision even if the TORU system malfunctioned.

In the end, NASA managers went along with the Russian proposal to redock the Progress.

Video vault
A time-lapse movie shows the Progress M1-4 cargo ship during its final approach and docking to the international space station.
  PLAY (360k, 60sec QuickTime file)
The Expedition One crew recorded this video showing large amounts of water pooling around various components in the condensate recovery system of the station.
  PLAY (245k, 30sec QuickTime file)

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