While NASA’s first manned spaceflight director, Chris Kraft, continues to be critical of the whole concept of building the new SLS heavy lift rocket system in favour of using current smaller launch vehicles, others remain concerned that NASA’s heavy lift rocket might actually still be too small itself. As Nasaspaceflight.com notes from NASA’s Concept Of Operations (CONOPS) document, using a four astronaut lunar lander similar to the origial Project Constellation Altair design would necessitate two Block 1A/B SLS launches for each mission and some complicated lunar orbit rendevous operations as well. This would be practically impossible to achieve given that six months are currently envisaged between SLS flights. It is no wonder that NASA’s Administrator, Charles Bolden, is so keen on exploring lassoed asteroids instead of going back to the Moon.
Via Chuck Black