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As mentioned in the YouTube clip below and in the image, in the Soyuz craft hangs small toys or dolls as microgravity indicators. Is this really the purpose of the dolls being hung? Are people not immediately aware, once they reach orbit, that they are in microgravity? If such an indicator is needed, what did NASA use for this purpose.

enter image description here

Soyuz, Expedition 52 Soyuz MS 05 Launch Coverage, Baikonur

Bob516
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2 Answers2

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As Organic Marble points out, yes the US space program had G meters. They're likely to include these in future manned missions, as well.

As for the true purpose of the toys: To humans, any sudden reduction in acceleration feels like falling. When the engines cut off, they are aware that there is less thrust, but the human body isn't great at telling you, definitively, that there is no thrust.

A person may believe they've reached null gravity in relation to their craft, but if there is residual thrust, the toy would show this more clearly that a person's body would, in an unambiguous way.

Instruments can have a (very, very, very small) chance to fail without indicating that they've failed. A toy on a bungee either shows that you're in free fall, it's stuck somewhere, or it has broken loose; the failure states are completely unambiguous. Once the initial feeling of falling/weightlessness is confirmed, the crew will also look at instruments and the ground control will check telemetry, but the toy is a great indicator that can be checked with the smallest of glances.

Plus, the Russian manned space program is full of fun and interesting traditions, including signing the door of your hotel room, planting a tree, and flattening coins on a railroad track. Having a mascot hang out with you on your mission is just great fun.

Ghedipunk
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    Don't forget urinating on the bus tire. – Organic Marble Jul 31 '19 at 00:05
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    That was in my rough draft, @OrganicMarble, but I started getting on a tangent about carrying urine around in a cup for those who didn't want to expose themselves right there... – Ghedipunk Jul 31 '19 at 01:41
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    I always wondered if the ladies participated. – Organic Marble Jul 31 '19 at 01:48
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    @OrganicMarble Yes, Valentina Tereshkova followed the cosmonaut tradition of urinating on the bus tire. See wikipedia. But what about Svetlana Savitskaya, the second female cosmonaut? – Uwe Jul 31 '19 at 14:37
  • @Uwe and the US female astronauts that have flown to the ISS on Soyuzes - Whitson, Nyberg, etc, etc, ?? – Organic Marble Jul 31 '19 at 14:40
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    @OrganicMarble From BBC "Nevertheless, male astronauts are still expected to leave their bus, unzip their suits and urinate on the back right hand tyre. Suit technicians then have to redo the palaver of zipping them all up again. Female astronauts have been known to bring vials of their urine to splash on the wheel." – Uwe Jul 31 '19 at 14:57
  • Hope we continue this tradition when we go back to our own spacecraft. – Nick S Aug 01 '19 at 01:41
  • This is what terrifies me most about going into space in a soyuz...what if you don't need to urinate before launch?? – Innovine Aug 01 '19 at 05:50
  • @NickS, seems that, two crewed missions into Crew Dragon flights to the ISS, we're not urinating on the tires of the Teslas. I am glad to see that we're signing the wall of the White Room, though, even if it isn't exactly white anymore. – Ghedipunk Nov 17 '20 at 07:57
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The original shuttle flight deck had a mechanical g-meter on the instrument panel. A reading of near-zero here was a cue that free fall had been achieved.

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(NASA photo, emphasis mine)

When the shuttles were modified to the 'glass cockpit' configuration, a virtual g-meter was included.

enter image description here

(reference, p. 2.7-15)

Organic Marble
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