But the plan to use hardware from previous space programs is a bit cobbled together. The Space Launch System, for instance, was originally designed for the Constellation program, a strategy set up under the George W. Bush administration to finish building the International Space Station and to reestablish a human presence on the moon. Congress mandated that the rocket reuse technology from the then defunct space shuttle program. But Obama canceled Constellation in 2010, and in 2017 Trump anointed the Artemis program, with the goal of finally sending people back to the moon and paving the way for exploring Mars. Again, the new plan required that NASA use some of the technology that had been developed for Constellation, which in turn entailed repurposing old space shuttle technology. These mandates were pushed by congresspeople representing regions that housed manufacturing centers for shuttle parts. But the carryover and conversion of those technologies have proved difficult. According to a report from the NASA inspector general, bringing the rocket parts into the modern era—for instance, replacing asbestos parts—and retrofitting them for a new rocket system has cost much more than anticipated.
Leave it to congress to throw a wrench in things.