During the time of USSR, Bulgaria participated in a space program Soyuz 33. Then the Bulgarian cosmonaut Georgi Ivanov together with his Rissian colleague Nikolai Rukavishnikov were launched into space in 1979.

The scientific program for the flight was prepared entirely by Bulgarian scientists, along with some of the equipment

as said per Wikipedia.

The launch was successful, however, a severe technical problem prevented success of the mission as the space craft had to return back to Earth.

Having in mind this was not a successful operation, I am not sure if it answers your question, but the information might seem curious and probably less known. Besides, I am a Bulgarian :)

During the time of USSR, Bulgaria participated in a space program Soyuz 33. Then the Bulgarian cosmonaut Georgi Ivanov together with his Russian colleague Nikolai Rukavishnikov were launched into space in 1979.

The scientific program for the flight was prepared entirely by Bulgarian scientists, along with some of the equipment

as said per Wikipedia.

The launch was successful, however, a severe technical problem prevented success of the entire mission as the space craft had to return back to Earth.

Having in mind this was not a successful operation, I am not sure if it answers your question, but the information might seem curious and probably less known. Besides, I am a Bulgarian :)