Nasawatch is still running some news bits about that NASA Powerpoint it got from last July that discussed just about everything on SLS and alternatives, including international partners and fuel depots.
…it is obvious that even a year ago pragmatic thought was given to how a variety of launchers could be used for human, cargo, and other launch purposes including ways that mission profiles (DRM 4) usually associated with a HLV could be accomplished in whole or in part by the use of expendable launch vehicles. A more detailed look at what was being reviewed last year can be found at “Human Exploration Framework Team Presentation Online“.
Duh. This was discussed last time people were fussing over SLS vs alternatives, about a year ago. I don’t recall seeing the previous year’s charts online, but NASA did do a good, pragmatic study, as reported here. The study took into account different mission scenarios, lift capacity to carry out those missions, and different combinations of rockets that could do it (existing or planned), plus the time required to build the different fleets of rockets and/or depots, complexity, and reliability. SLS would cost more, but turntimes between missions are less and it’s not so complex.
If you replace SLS with a fleet, you still have to build the fleet at the right time and get them all into space when you need them, without anything going wrong.
Maybe Congress just wanted an SLS because it’s tall and looks cool. Maybe they looked at all the numbers and decided to keep it simple. (And then there may be uses for it they don’t want to talk about.)Share