She was a stray pup in the streets of 1950’s Moscow. She couldn’t have known that her motherland, the Soviet Union, was in a mad race to be the first to put a man in space. They would start with a dog. And so Laika, as she was named— the most common name one could give to a dog (“barker”, it meant)— was plucked off the street one night. She was a good dog, with a sweet disposition, obediently complying with the rigorous training of the space exploration program. And here is the duplicity of the situation: the lead scientist, Oleg Gazenko, developed a bond with her, even demanding that a window to be installed in her tiny space shuttle. The day of the launch of Sputnik II came in 1957, and after Laika was strapped in, he remained by her side on the platform. He knew she was doomed— the shuttle was designed to not be retrievable. He knew her death would be agonizing, a result of stress and overheating. Many years later he would recall how he walked past the post-launch reception and out into the nearby forest, where he cried. “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,” he said in a public statement in the late 1990’s, after the Soviet Union was no more.

Regret is a running theme in Maximum Tolerated Dose—the first feature length documentary on animal testing. Part of the story is told through revealing testimonials of vivisectors who had a crisis of conscience at one point during their research— like the cardiologist, who finally made the connection between the dogs he was experimenting on for work and his beloved pet dogs at home; or the lab worker who bonded with the rats from her lab. They made the decision to walk away from animal testing forever, unable to compartmentalize their inherent compassion any longer.