In 2017, NASA announced that the ASU-led Psyche mission would launch one year early, in summer 2022.
But logistical problems have pushed its take-off back and left its future unclear.
NASA says late delivery of testing software and equipment mean the Psyche team cannot finish final systems checks before the launch season ends Oct. 11.
That removes a chance at a shorter travel time and, because nothing in space stands still, means a possible launch in 2023 or 2024 will entail a longer, six-year flight.
Part of NASA's Discovery Program of low-cost, competitive projects, the agency's first mission designed to study a metal-rich asteroid has spent $717 million of its $985 million budget.
An agency team will consider how to proceed from here.