The National Aeronautics and Space Administration's investigation into Boeing's failed December spaceflight came up with a long list of corrections needed before the company flies again.

Boeing said Friday that the investigation found about 61 "corrective actions" for the company's Starliner spacecraft, which it has been developing to fly NASA astronauts. NASA associate administrator Doug Loverro told reporters on a conference call that he expects it "will take several months" for Boeing to work through the list.

"This was a close call. We could have lost a spacecraft twice during this mission," Loverro said.

The 61 recommendations are not each individual problems with the spacecraft, Boeing said, as there are three primary technical and design issues that the company is addressing. However, Loverro noted that does not mean there are only three problems with Starliner. He said there are more issues, although he wasn't sure of a specific number identified by investigators.