A glitch has struck the Yutu rover.
The Sun recently set on Sinus Iridum, landing site of China’s third lunar mission. The sunset kicks off two weeks of lunar night, during which the solar-powered Chang’e 3 lander and rover are supposed to hibernate. This is the second lunar night Chang’e 3 has experienced. The lander’s main color camera didn’t survive the first. Now, while preparing for bed for the second night, something went wrong with the 120-kg (260-pound) Yutu rover.
The English-language news outlet Xinhua reported on January 25th that the rover had experienced “a mechanical control abnormality, and scientists are organizing repairs.” This abnormality was caused by the complex and harsh lunar surface environment, according to a statement from China’s State Administration of Science, Technology, and Industry for National Defense (SASTIND).
To survive the night’s bitterly cold temperatures (dropping as low as -180° Celsius, or -290° F), Yutu is supposed to carefully hunker down. Its color camera and high-gain antenna are attached to a central mast, which folds down against the rover’s body. Once that is secured, one solar panel folds over the instruments like a blanket, tucking the equipment in with a radioisotopic heater against the frigid night. The rover points the other solar panel towards the horizon to catch rays from the Sun when it rises again.
While reports are vague, it sounds like some part of the origami sequence malfunctioned before Yutu went into full hibernation. Depending on what exactly happened, this glitch could be fatal to Yutu. The team probably won't confirm the rover’s fate until the Sun rises on Sinus Iridum in about a week and a half. For now, both the rover and lander — which successfully entered hibernation — are dormant.
Even if the rover has failed, it has about 40 days of work under its belt and has logged more than 100 meters (300-plus feet) across the Moon’s surface, following its successful landing in December.
The robotic mission also returned great panoramas of the lunar surface and the first views of Earth from the Moon in more than 30 years, pictured below.
Poignant messages written in the rover’s voice have appeared on social media and in news coverage. Our favorite is the sign-off message in one blog (based on Google translate): “Goodnight Earth. Goodnight humanity.”
We’ll have to see whether Mark Twain’s famous line comes back to prove these farewells premature.