Bulgaria, Czechoslovakia, East Germany, Hungary, Poland, and Romania were the Soviet satellite states that formed in the Eastern bloc of Europe. Those nations were part of the Warsaw Pact, signed along with the Soviet Union in 1955. The name of that pact stems from the facts that the agreement was signed in Warsaw, Poland. Albania also was an original signer of the Warsaw Pact, but split its relationship with the Soviet Union some years later.
Prior to the end of World War II, British Prime Minister Winston Churchill and US President Franklin Roosevelt pushed strongly for Soviet leader Josef Stalin to allow free elections to take place in the nations of Europe after the war. Stalin had stated agreement with his fellow Allied leaders. But after the war ended, Stalin and the Soviets never did allow those free elections to occur. The Soviets felt they needed the Eastern European nations as satellites to protect their own interests. A line of countries in Eastern Europe came into line with the USSR and communism -- thus called "satellites."
Indentured servitude differed from slavery in that it was a form of debt bondage, meaning it was an agreed upon term of unpaid labor that usually paid off the costs of the servant's immigration to America. Indentured servants were not paid wages but they were generally clothed and fed