Another day, and another iconic space mission has gone dark. On Tuesday, NASA announced that its exoplanet-hunting Kepler Space Telescope had run out of hydrazine fuel, and the craft would be commanded to cease operations. Now, the Dawn spacecraft at the dwarf planet Ceres must face the same fate.
On Wednesday, the spacecraft failed to phone home, and it missed a scheduled connection on Thursday as well. This means that, like the Kepler mission, Dawn has run out of hydrazine fuel, which the vehicle needs to orient itself and keep its antennas aligned with Earth. With no fuel, the spacecraft also cannot keep its solar panels turned toward the Sun.
This was not unexpected. Prior to this, because NASA did not want to potentially contaminate the surface of Ceres due to planetary-protection concerns, mission controllers placed Dawn into an orbit around Ceres that will remain stable for decades. It is now a silent sentinel in orbit around the dwarf world it has studied since 2015.