ISS will continue well past 2020. At least until 2024 and possibly 2028. Here's one article in the affirmative: http://www.interfax.com/newsinf.asp?id=530860That means we could see commercial vehicles servicing the ISS for 8 - 10 years. This should give ample time for other LEO destinations and capabilities to emerge and create a real commercial market. I truly think this program will go down as one of NASA's greatest enabling achievements. IMO, once Dragon & DC (my choice) begin these services, a huge amount of interest from other countries (and companies) will propel this nascent industry. That these vehicles will have been certified by NASA and will launch with at least one Russian Cosmonaut per mission, will lend a lot of credibility to these commercial systems. The mission operations experience SpaceX and SNC will obtain will be monumental and leveraged in ways we may not even be thinking about yet.Heading into the later part of this decade with SLS, DC and Dragon all operational? The possibilities are endless. The likes of which we haven't seen before. All I have to say is...Thanks NASA. I know I don't always say it and yes I get frustrated with you but...well, thanks for this one. You've made us all very proud and extremely excited.