>>83185671. The dotcom bust followed by 9/11 and the wars in Iraq and Afghanistan happened. Money was siphoned off into the creation of the DHS, and the government doubled down on the V-22 and F-35 projects instead of Constellation. Shit happens. When Columbia blew up in 2003, people chalked it up to a random tragedy and not something that could have been prevented with a better vehicle.
2. Then, right as the Surge (which cost a lot of money) began, the economy collapsed in a way not seen since 1929. It still hasn't recovered and the government doesn't exactly know how to handle it. Take a look at how noncommittal the FRB is toward interest rate hikes right at this very moment. Money was funneled into the Troubled Asset Relief Program and the original stimulus. The F-35 and V-22 projects gave us flyable aircraft around this time, just as NASA went to reorganize.
3. Constellation itself couldn't get off the ground due to technical issues with trying to get Ares-1 to work, so it was scrapped and it's core components (Orion, Ares V/SLS, Altair) will be handled individually. As such, there's only about a +10 year delay to NASA's plans and not +20.
4. Ultimately, trying to plan something as nebulous, fickle, and expectedly failure-prone as spacecraft engineering out for 50 years as Constellation did isn't feasible. The fact is, Constellation is better as a "mission statement" or a "guide" than it is a formal roadmap.
