The original budget for it was on the low side. It's launch budget went to the lowest bidder - SpaceX at $69m ( https://www.nasa.gov/press-release/nasa-awards-

The original budget for it was on the low side. It's launch budget went to the lowest bidder - SpaceX at $69m ( https://www.nasa.gov/press-release/nasa-awards-launch-services-contract-for-asteroid-redirect-test-mission https://www.nasa.gov/press-release/nasa-awards-launch-servic... ). The mission as approved 3 years before Arecibo collapsed and final assembly of the spacecraft was done half a year before. https://cosmosmagazine.com/space/dart-timeline-from-build-to-spacex-to-impact/ https://cosmosmagazine.com/space/dart-timeline-from-build-to... The loss of Arecibo was a loss to the mission as the pictures that you most often see of Didymos were from Arecibo. The mission itself was also a technology demonstration of a camera, autonomous navigation using that camera, solar arrays, new antenna, and ion thruster design. https://en.wikipedia.org/wiki/Double_Asteroid_Redirection_Test#Spacecraft https://en.wikipedia.org/wiki/Double_Asteroid_Redirection_Te...