The newspaper Komsomolskaya Pravda says the 18-year-old female donkey called Anapka died of heart trouble after falling ill in December.
Anapka had been sent up into the sky over a southern Russian beach in a promotional stunt, and the YouTube video of her trip made headlines around the world. The donkey was brought to Moscow in August.
Anapka spent her final months on a farm outside the city, where the major Russian newspaper said she lived out her remaining days in luxury, eating fresh fruit and vegetables, getting massages and even spending time in a solarium.
The newspaper did not say when she died.