First, I want to note that I am very interested in the CSTS study, it seems to be something ESA memberstates might really want to do, if there is a good proposal on the table in 2008.<br /><br />The problems I see are as follows:<br /><br />1. According to this new information, ESA also wants to develop the new propulsion module. This makes sense from ESA's viewpoint, because the habitation module alone is not enough to be considered an equal partner. The problem I see is from the Russian side. If the CSTS-spacecraft really will replace the Soyuz at some point, Russia will be dependent on Europe for parts of its spacecraft and vice versa ESA. Politicians might view that as problematic.<br /><br />2. Ok, let's take Mario Valls by his own words and presume this is not merely a Soyuz upgrade, but a re-design. Let's further presume they will go for a crew of four. That means that spacecraft has to be more massive than the Soyuz-TMA and not even a Soyuz 2-1b will be able to lift it to orbit. Is it already certain that the Soyuz 2-3 is going to be developed? As far as I know until now there was a lot of talk, but there haven't been any approved concepts, not even mentioning appropriate funds allocated to that launcher development. Ariane 5 or Proton are out of the question of being used, because the CSTS will primarily just replace the Soyuz TMA for missions to the ISS. To use Ariane 5 would just be a waste of money for that kind of missions.<br /><br />3. How do lunar missions really fit into that concept? While I have no doubt that a circumlunar flight can be done (it can actually even be done with a Soyuz spacecraft) with 2 flights, I am very sceptical about anything that goes beyond that. <br />A mission to lunar orbit would be fairly complicated, if the CSTS-concept wants to use current rockets. I doubt that it can be done even with 3 launches (2 Protons or Ariane 5s and one Soyuz 2-3). And while doing a moon mission with 2 launches stacked together in Earth orbit is complica