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

  • 1
    $\begingroup$ Apparently these toys go back to at least 1985, if not earlier. They are portrayed in the Russian film Salyut-7. See the bear in this screenshot from this review of the film. $\endgroup$
    – DrSheldon
    Sep 3, 2019 at 7:35

2 Answers 2


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.

  • 14
    $\begingroup$ Don't forget urinating on the bus tire. $\endgroup$ Jul 31, 2019 at 0:05
  • 7
    $\begingroup$ 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... $\endgroup$
    – Ghedipunk
    Jul 31, 2019 at 1:41
  • 3
    $\begingroup$ I always wondered if the ladies participated. $\endgroup$ Jul 31, 2019 at 1:48
  • 1
    $\begingroup$ @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? $\endgroup$
    – Uwe
    Jul 31, 2019 at 14:37
  • 4
    $\begingroup$ @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." $\endgroup$
    – Uwe
    Jul 31, 2019 at 14:57

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.

enter image description here

(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)

  • 1
    $\begingroup$ Is there a situation in the Shuttle's normal flight profile in which it would have actually been experiencing negative G's? $\endgroup$
    – Skyler
    Jul 31, 2019 at 19:00
  • $\begingroup$ Also curious about the negative g, on which axis is this being measured? $\endgroup$
    – Innovine
    Aug 1, 2019 at 5:53
  • $\begingroup$ Ask a new question please - since I'll have to research it. $\endgroup$ Aug 1, 2019 at 11:33

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.