From the wiki article:
It was not until 1998, after the collapse of the Soviet regime, that Oleg Gazenko, one of the scientists responsible for sending Laika into space, expressed regret for allowing her to die:
"Work with animals is a source of suffering to all of us. We treat them like babies who cannot speak. The more time passes, the more I'm sorry about it. We shouldn't have done it... We did not learn enough from this mission to justify the death of the dog."
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Truth does not need us to talk about it to be True. We simply need to open our eyes and see, open our ears and listen.