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MS. STILSON:  Chloe from Scranton asks why will the Space Station's robotic arm move the Raffaello module this time

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instead of how it was done in previous flights where the Space Shuttle's robotic arm was used.

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Is this a mechanical issue or related to a safety issue?

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MR. HIGGINBOTHAM:  Well, that's an excellent question, Chloe. You're right. On all previous missions, we used the Shuttle's arm

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to lift the MPLM that was flying and pick it up and attach it to the node of the Station. However, on this mission,

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we're flying the Orbiter Boom Sensor System for the first time. This boom sensor system is mounted on the orbiter payload bay,

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on the opposite side from where the Shuttle arm is. And, unfortunately, it's in the way of the MPLM when it comes time to remove it

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and put it back in place. So on flight-day three, just right after we dock to the Station, the crew is going to use the Station arm

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to actually pick up the OBSS, hang it out in space, and hand it off to the Shuttle arm,

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which will then deploy it out away from the Station in the Shuttle.

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This will clear the way for the subsequent unberthing and docking of the MPLM to the Space Station. It also clears the way for the ESP-2

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and the newer activity that is going to take place on the third EVA of the mission. Basically, with the OBSS being added to the flight,

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we needed to get it out of the way. And the way we're going to do it is do this hand-off.

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And so the Station arm, which is perfectly capable of doing the job,

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will lift the MPLM up and attach it to the Station and then put it back when we're done.

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MS. STILSON:  That was our last question for you, Scott. Thank you so much for being a part four show.

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MR. HIGGINBOTHAM:  You're quite welcome, Stephanie.

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