One of former NASA Deputy Administrator Lori Garver’s indictments against the heavy lift Space Launch System is that it is based on “50 year old technology,” according to a January 2, 2014 account in Space Policy Online. The implication is that whatever sends American astronauts beyond low Earth orbit should be developed from cutting edge, 21st Century technology.
As it turns out, Garver was being somewhat misleading. While it is true that the Space Launch System is based on legacy hardware developed for both the space shuttle and the Saturn V, NASA is developing methods to manufacture the big rocket that are decidedly futuristic.
For example, NASA reported in 2012 that a new method of manufacturing, known as selected laser melting or SLM, similar to 3D printing, is being used to create Space Launch System parts. More recently the space agency successfully tested a rocket engine injector created by 3D printing. The 3D printer injector had only two parts as opposed to 115 in a conventionally created injector. Fewer parts means less assembly required and lower costs. NASA hopes to apply the same method to the RS-25 engine which will be used in the Space Launch System.
Garver was being somewhat vague about what she thought should replace the SLS. One could be forgiven for suspecting that nothing would replace the heavy lift rocket should it be cancelled, effectively ending human space exploration by Americans for yet another generation.