To learn more about what's happening on the International Space Station at any given time, check out NASA's frequently-updated ISS blog or their page about the research and development work happening on ISS.
Depends on your body type and metabolism and your routine. But usually it takes around 3 to 4 weeks for visible results. For me it took me a couple of months to actually see any progress visually.
If you follow this program and stick with it and never give up you will see increased muscle mass within 21 days. Every individuals body is different, we all grow at a different pace, stick with your routine and stay focused and you will see results in as little as 21 days.