It's frequently claimed without citation that Alexey Leonov carried a poison pill of some kind during his Voskhod 2 spacewalk mission, to commit suicide should he be unable to re-enter the spacecraft. Examples: here, here.
This seems unlikely:
- As American astronauts such as Jim Lovell have stated, simply depressurizing a suit or spacecraft would be a quicker and more comfortable method of suicide.
- Any poison pill intended for use in a spacewalk would have to be accessible by mouth alone inside the helmet, which presents a possibility of accidental ingestion.
I'm taking Lovell at his word that the American program never included poison pills:
Since Apollo 13 many people have asked me, "Did you have suicide pills on board?" We didn't, and I never heard of such a thing in the eleven years I spent as an astronaut and NASA executive.
There is no mention of suicide pills in Asif Siddiqi's extremely thorough history of the USSR's early space program (part 1, part 2). A search of the text for key terms "poison", "cyanide", and "suicide" yield references to an automated poison injector for Laika's benefit, but nothing related to human cosmonauts.
Mary Roach, in Packing For Mars, casts doubt on it:
Space physiology expert Jon Clark told me the [Leonov] suicide pill story is most likely untrue. I had emailed Clark at his office at the National Space Biomedical Research Institute regarding the perplexing logistics of pill-popping in a spacesuit, and he did some asking around. His Russian sources also dismissed another rumour, that Belyayev was under orders to shoot Leonov if he couldn't get back in...
The 1997 document Walking To Olympus states:
Leonov recently revealed that he had a suicide pill he could have swallowed if he had been unable to ingress Voskhod 2 and Belyayev had been forced to leave him in orbit.
I followed up the citations from that article; the most likely source for this statement is “Orbital Castling: Life of Mir Station Will Be Prolonged Three More Years,” Segodnya in Russian, May 11, 1995, p. 9. Translated in JPRS Report, Central Eurasia: Space, August 2, 1995 (FBIS-UST-95-030), p. 20, but I can't find the article online.
Is there any credible evidence that any cosmonaut carried poison pills, or for that matter any other device primarily intended for suicide?