What's the meaning of the tethered/strangulated Snoopy on the SMEAT/Skylab preparation mission patch?

In preparation for the manned Skylab missions, a "Skylab medical experiment altitude test" was performed with astronauts living for an extended period in a simulated environment. The mission patch shows the cartoon character Snoopy drifting in space, with a piece of rope around his neck.

What's the symbolism of the SMEAT mission patch?

I know that Snoopy was a semi-official mascot of the Apollo programme, but what is the particular meaning of Snoopy being tethered and apparently quite unwell and unhappy?

The (otherwise excellent) book Homesteading Space, while covering SMEAT and calling it a "plum assignment", only briefly mentions the patch, and that the crew originally had asked for a fish-hook catching Snoopy, which was changed to a rope at Schultz' insistance, but I still don't get it.

chatGPT has at times suggested it refers to Snoopy being "grounded" (like the participating astronauts -- but Snoopy is depicted floating in space), or "rope" being an engineering term for crucial tests, but both don't ring true.