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Raumfahrt - ISS-ALLtag: EVA-46 - Astronauts Prep for Spacewalk and Check Science Gear

17.10.2017

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Astronaut Mark Vande Hei is pictured tethered to the outside of the U.S. Destiny laboratory module during a spacewalk on Oct. 10, 2017.

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Two NASA astronauts are getting ready to go on their mission’s third spacewalk on Friday. In the midst of those preparations, the Expedition 53 crew also worked on science gear exploring a wide variety of space phenomena.

Commander Randy Bresnik is preparing to go on the third spacewalk this month with NASA astronaut Joe Acaba. Astronauts Paolo Nespoli and Mark Vande Hei will assist the spacewalking duo in and out of their spacesuits on Friday.

The spacewalkers will replace a camera light on the Canadarm2’s newly-installed Latching End Effector and install a high-definition camera on the starboard truss. Other tasks include the replacement of a fuse on Dextre’s payload platform and the removal of thermal insulation on two electrical spare parts housed on stowage platforms.

Bresnik started his day working on a specialized camera that photograph’s meteors entering the Earth’s atmosphere. Acaba finally wrapped up the day configuring a microscope inside the Fluids Integrated Rack.

Nespoli, from the European Space Agency, set up the new Mini-Exercise Device-2 (MED-2) for a workout session today. Researchers are exploring the MED-2 for its ability to provide effective workouts while maximizing space aboard a spacecraft.

Quelle: NASA

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Update: 23.10.2017

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Astronauts stage third spacewalk in 15 days

A high definition video camera installed outside the space station Friday captures a crystal clear view of astronaut Joe Acaba working at one end of the lab's robot arm.

 
 NASA

Staging NASA's third spacewalk in 15 days, two astronauts floated outside the International Space Station Friday and installed a new high definition camera, replaced a degraded camera on a recently attached robot arm grapple fixture, finished lubricating the mechanism and carried out a variety of other "get-ahead" tasks.

The only items the crew missed were two low priority get aheads, the attachment of a handling fixture on a spare radiator assembly to make it easier to move later and bolt adjustments on another piece of backup gear.

But all of their primary tasks were accomplished, including replacement of a fuse in a payload carrier used by an appendage of the robot arm and work to rig several spare components for quick access if they are ever needed.

Floating in the Quest airlock, station commander Randy Bresnik and Joe Acaba switched their spacesuits to battery power at 7:47 a.m. EDT to officially kick off the year's tenth spacewalk, the third in the past two weeks.

The spacewalk originally was planned for Wednesday, but it was delayed two days after engineers discovered a camera-light assembly on the robot arm grapple fixture that was installed during an Oct. 5 spacewalk was not focusing properly. The camera provides the bird's eye view needed for the arm to capture visiting cargo ships and other components.

Acaba, anchored to the end of the robot arm, first installed a new high definition camera on the lower right side of the station's long power truss.

While Acaba was setting up the arm for the camera installation, Bresnik replaced the fuse in the robot arm payoad carrier and then brought out a replacement safety tether after loose stitching was seen on one of the redundant tethers securing Acaba to the station.

With the tether replaced, Bresnik removed insulation from a spare electrical distribution box known as a main bus switching unit, or MBSU, and tied back insulation on another component known as a direct current switching unit, or DCSU.

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A spectacular view of the space station as astronaut Randy Bresnik, left, and Joe Acaba return to the Quest airlock to wrap up a successful six-hour 49-minute spacewalk.

 NASA

Getting the insulation out of the way will enable the robot arm to grapple either unit down the road if failures occur and the spares are needed as replacements.

After installing the new HD camera, Acaba got off the arm, anchored himself to a foot restraint on the truss and removed the camera assembly on the robot arm grapple fixture, known as a latching end effector, or LEE.

After removing the degraded camera, Acaba installed a replacement that he carried outside earlier. Engineers powered up the arm and the camera worked as expected.

Acabs then used a grease gun to lubricate the grapple mechanism, work that was started during the Oct. 5 spacewalk. Toward the end of the work, flight controllers noticed a handle on Acaba's emergency jetpack had popped open.

The nitrogen-powered jetpacks worn by all NASA spacewalkers are designed to allow an astronaut to "fly" back to station if he or she somehow got disconnected from safety tethers. Acaba was firmly tethered throughout, and he was told to complete the lubrication work before heading back to the airlock.

Repressurization began at 2:36 p.m., closing out a six-hour 49-minute spacewalk.

This was the 205th EVA devoted to station assembly and maintenance since construction began in 1998, the fifth overall for Bresnik and the third for Acaba. One hundred and 24 astronauts and cosmonauts representing 10 nations have now logged 1,278 hours and 25 minutes of station EVA time, or 53.3 days.

Quelle: CBSNews

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