How is this NASA's failing? A congressional mandate to fund and build this regardless of the agencies needs is the failure. There's no need to display the agency in a bad light, especially if you have the information about what happened and show it was caused by other government involvement.
Who says it was their failing? Drift just means being pushed from one's target. It is acceptable (and usual) for drift to be caused by external forces.
I think drift in this case has a connotation of being aimless and directionless (eg being adrift). However, I don't think the article is blaming NASA. Any organization would be adrift after having the kind of success NASA did, then getting presidential grandstanding followed by congressional micromanagement for decades.
The real villains in this story are Congress and the President.
