In the first video in our two part series on HIV and AIDS, we explain how scientists figured out what HIV is, when the infection morphs into AIDS, and where they think the virus originated.

Howcast - Learn how and when HIV becomes AIDS from sexpert Jane Bogart in this Howcast video.

Aaron Allcorn and Tom Williams discuss NASA’s efforts to understand the optimal spaceflight environment that maximizes human performance. This is part two of a six part series on NASA’s Human Research Program. HWHAP Episode 124.