As one of a dozen or so rituals introduced by Yury Gagarin in 1961, Russian cosmonauts relieve themselves on the right-rear wheel of the bus that takes them to the launch pad, for reasons unknown to mere mortals. (Women cosmonauts sometimes bring vials of their urine to keep the tradition going.)

A cosmonaut tradition set by the first man in space is under threat with Russia’s new spacesuit design.

A new spacesuit unveiled at the Moscow International Air Show MAKS 2019 this week doesn’t allow for this ritual because it lacks a fly zipper — but its designer was nonplussed about the oversight.

"I'm not sure how they will be able to [relieve themselves], since we haven't designed the fly," Sergei Pozdnyakov, head of the Zvezda research and development company, told reporters.

"We have the design specifications. Nowhere do they say that you have to pee on the wheel," Pozdnyakov was quoted by the state-run RIA Novosti news agency as saying Thursday.

However, he boasted that cosmonauts will be able to put on the new Sokol-M custom-made spacesuit in half the time it currently takes to do so. Tests of the multi-use Sokol-M, which was designed to be worn aboard new spacecraft that will replace current launchers, are expected to start in 2020.