President Carter aborted the operation after only five of the eight helicopters he had sent into the Dasht-e Kavir desert arrived in operational condition. As U.S. forces prepared to depart from the staging area, a helicopter collided with a transport plane, causing a fire that killed eight servicemen. Vance's resignation was confirmed several days later, and he was replaced by Senator Edmund Muskie. A second rescue mission was planned but never carried out, and the diplomatic efforts to negotiate the release of the hostages were handed over to Deputy Secretary Christopher. The hostages were released during the first inauguration of Ronald Reagan, after 444 days in captivity.