After the flight team eliminated other possible causes for the missed communications, mission managers concluded that the spacecraft finally ran out of hydrazine, the fuel which keeps the spacecraft oriented and in communication with Earth, NASA said in a statement late on Thursday. The 11-year mission to investigate “time capsules from the solar system’s earliest chapter” in the asteroid belt concluded after Dawn finally ran out of hydrazine fuel, which meant it could no longer turn to face Earth, to communicate, or the sun, to recharge. Dawn, a NASA spacecraft that launched 11 years ago and studied two of the largest objects in the asteroid belt, has ended its mission after running out of fuel, officials said Thursday. Now that it’s no longer capable of communicating, much less maneuvering, it is expected to remain in orbit around Ceres for decades or longer. It’s hard to say goodbye to this amazing spaceship, but it’s time.”

Thomas Zurbuchen, associate administrator of the NASA science mission directorate in Washington, hailed Dawn’s “vital science” and “incredible technical achievements.”

Dawn became the only spacecraft ever to orbit a cosmic body in the main asteroid belt between Mars and Jupiter in 2011 when it began circling the asteroid Vesta. “The astounding images and data that Dawn collected from Vesta and Ceres are critical to understanding the history and evolution of our solar system.”

Dawn was a mission of firsts, as it not only became the first spacecraft to orbit a celestial body between Mars and Jupiter (Vesta, the second-largest body in the main asteroid belt) but also the first to visit a dwarf planet and orbit two planetoids other than Earth. Dawn performed several firsts in space exploration: It was the first and only mission to visit both Vesta and Ceres, NASA's first deep space mission to use ion propulsion, and the first mission to orbit more than one target body beyond the Earth and Moon. “The fact that my car’s license plate frame proclaims, ‘My other vehicle is in the main asteroid belt,’ shows how much pride I take in Dawn,” says mission director and chief engineer Marc Rayman at NASA’s Jet Propulsion Laboratory (JPL). "The demands we put on Dawn were tremendous, but it met the challenge every time," said Marc Rayman, mission director and chief engineer at NASA's Jet Propulsion Laboratory, in a statement.
NASA's Dawn spacecraft exhausts all of its hydrazine fuel propellant and without a functioning maneuvering system enters into uncontrolled motion around dwarf planet Ceres, thus ending its 11-year mission.