The competition between the U.S. and Soviet Union to be the first to land humans on the Moon during the 1960s takes a personal turn in a new television mini-series to air Sunday.

Instead of focusing on astronauts with the right stuff or spaceships, the National Geographic Channel's "Space Race: The Untold Story" spotlights two scientists - Wernher von Braun with NASA and Soviet Union chief designer Sergei Korolev - as they pushed rocket technology from its ballistic missile roots to the high frontier.

Based on the book of the same name by Deborah Cadbury, the two-part "Space Race" delves deep into the personal lives of von Braun and Korolev as the competition for ever-more advanced rocket technology during the Cold War between the U.S. and Soviet Union sent them on their respective paths.

"It's a very unusual tale of rivalry because obviously in America, with a free western press, everything that von Braun did was totally visible to Korolev," Cadbury told SPACE.com. "From von Braun's point of view, his rival in the Soviet Union was totally hidden."

By drawing on unclassified documents both the U.S. and Russia, provides a balanced look at the two nations' space efforts, rather than the typically U.S.-heavy accounts related in the past. A treasure trove of Korolev's personal history obtained from the family his former biographer, as well as actual video of Russia's first R-7 rocket launches, failures, and successes - such as cosmonaut Yuri Gagarin's first spaceflight in 1961 - cap "Space Race's" effort to recreate the country's orbital ambitions, Cadbury said.

Korolev's rise from a lowly prisoner to chief rocket designer is as remarkable as von Braun's history as an S.S. officer with the Nazi Party during World War 2 is shady. "Space Race" does not let the legacy von Braun, who died in 1977, come clean of the slave labor used to build the V2 rockets designed by the German scientist's team during the war.

"There are at least two documents that show he was involved in recruiting skilled labor for the V2 rocket program," Cadbury said.

In her book, Cadbury adds that concentration camp survivors also published eyewitness accounts of von Braun and the V2 slave labor use after the rocket scientist's death. But during the space race's formative years, his role was played down by the U.S. officials, she said.

"At that time, America was in its full glorious years and von Braun's past had been very cleverly concealed," Cadbury said.

It's important to note that Space Race is not an exact account of how post-World War 2 events spiraled into a competition to reach for the Moon. Rather, the mini-series uses its central characters as devices to explain personal motivations - von Braun's enthusiasm for space exploration, for example - while remaining true to the overall timeline of events. The mini-series also relies heavily on narration, recreation and character exposition to relate the technical challenges of human spaceflight.

"You always worry about oversimplification," Cadbury said, adding explaining the evolution of rocketry and astronautics accurately and simply was one of the "Space Race" project's main challenges.

"Space Race" stops just as the U.S. reaches the Moon and the Soviet Union - bogged down by multiple failures if its N-1 rocket - bows out of the lunar competition. Concluding there is unfortunate, given that the amount of space cooperation that later followed between the two world superpowers.

The joint Apollo-Soyuz project in 1975 brought the two former enemies together in space for the first time during an unprecedented orbital docking.

Russia continues to be a powerful ally for NASA in the International Space Station project, a partnership that also includes the European Space Agency and a number of other participating nations.

"It's wonderful to see the two countries collaborating in this venture," Cadbury said. "You kind of feel that this can only be to the human good."

"Space Race: The Untold Story" will air June 4-5 at 9 p.m. ET/PT (check local listings) on the National Geographic Channel.