BEIJING, March 15 -- In China's previous space missions, astronauts like Yang Liwei emerged as heroes, but in the country's third lunar exploration, a robot has unexpectedly grabbed the nation's heart.
Lunar rover Yutu, or Jade Rabbit, roused from its third lunar night slumber on Friday, stretching its wings in the sun after its dormancy in temperatures as low as minus 180 degrees Celsius. People on Earth were relieved by its greeting on an online diary posted under the name "Lunar Rover Yutu."
"Don't poke me... I'm already up!" the six-foot robot told the 600,000-strong followers of the blog, who had been crossing their fingers that the rover would survive its second sleep since a mechanical abnormality was spotted at the end of January.
"Any carrot pie for me?" Yutu asked upon waking on March 14, a day celebrated by mathematics enthusiasts as "Pi Day" in honor of the famous ratio's first few digits, 3.14.
Named after the pet rabbit of moon goddess Chang'e from Chinese legend, the lunar rover largely stayed out of the spotlight until news came that a mechanical control abnormality prior to its second dormancy might cripple the robot.
The news meant that Yutu might never wake up when dawn greeted the moon.
The vehicle had been on the moon for 42 days and traveled for more than 100 meters when its second lunar night, equivalent to a fortnight on Earth, fell on Jan. 25. The mechanical errors posed a survival challenge for the country's first moon rover.
Online communities worried about the fate of Jade Rabbit after a post on Sina Weibo, China's answer to Twitter, said, "Ah, I'm broken," telling people that the rover "might not make it through this moon night."
"I thought I could hop around here for three months, but if this trip ends prematurely, I'm not afraid," said the blog entry.
The unverified Weibo account "Lunar Rover Yutu" began keeping a diary for the robot, written in a rabbit's voice, on Dec. 1, one day before the rover's launch.
The farewell message attracted broader attention to both the rover and the blog account.
Its last words, "Good night, Earth. Good night, humanity," prompted both tears and prayers from "rabbit fans."
Blessings flooded social media and the blogosphere, with fans saying, "Wake up, rabbit!" and "Come on, bunny! We all stand by you!"
The Weibo account remained silent for two weeks, with its followers prepared for the worst until Feb. 13, when the robot announced its survival by asking, "Hi, anyone there?"
The post went viral with over 119,000 reposts, 72,000 comments and 85,000 likes. Even overseas netizens and media joined to hail Yutu's survival.
"YIPPEEE!!! Nice!! I read the headline and I cheered so loud, I fear my neighbors might think I'm nuts... lol! That's so cool for China, the mission and space exploration in general!" wrote user Jeffrey Boerst in the comments section of an article from Universe Today, a space and astronomy news site.
The report began with the two-word lead "Yutu Lives!" and referred to the rover as "the little 'rabbit' beloved worldwide."
TO THE MOON
The bunny embarked on its adventure on Dec. 2, when an enhanced Long March-3B rocket carrying its mothership, the Chang'e-3 lunar probe, blasted off at the Xichang Satellite Launch Center in southwest China.
Before the launch, the "Yutu Lunar Rover" blog reported that the rabbit was "a bit nervous."
A major challenge for the 140-kg robot was the 300-degree Celsius temperature fluctuation on the moon. When the sun sets, the solar-powered rover must hibernate and survive the night with a radioisotope heat source.
After traveling for 12 days, Chang'e-3 touched down on the moon's Sinus Iridum, or the Bay of Rainbows, on Dec. 14, becoming China's first spacecraft to soft land on the surface of an extraterrestrial body. China is the third country to carry out such a rover mission after the United States and the former Soviet Union.
Yutu separated from the Chang'e-3 mothership lander the next day and set foot on the moon, which had not been visited for 38 years since a Soviet Union probe landed in 1976.
And then Yutu and the lander began taking pictures of each other after Yutu moved to a spot about nine meters north of the lander.
In a color image, the "rabbit" spreads its arms and "stares" at the camera while bearing a Chinese national flag.
The photographs marked the "complete success" of the Chang'e-3 mission, according to Ma Xingrui, chief commander of China's lunar program.
Yutu is tasked with surveying the moon's geological structure and surface substances and will also look for natural resources for three months using its radar, panoramic camera, particle X-ray device and infrared imaging equipment.
So far it has collected a large number of scientific images and data, including a 360-degree landscape photo and over 11,000 pieces of data about the moon's surface structures. It has also sampled lunar rocks for analysis back on Earth, according to the State Administration of Science, Technology and Industry for National Defense (SASTIND).
WILL IT BE BACK?
Yutu's waking from its third dormancy suggests that the lunar rover has survived its design life of three months.
With its mechanical abnormality still unsolved, the ailing rover will continue to work, roaming on the moon while commanded by the mission control center, according to SASTIND.
Scientists are still working to check and solve Yutu's mechanical abnormality, hoping it can live as long as possible. Chang'e-2, China's second lunar probe, has been working nearly three years longer than its expected life and is currently 70 million kilometers from Earth as China's first man-made asteroid.
"We hope it will live longer and go on working. We don't mind staying up working every night," said Ye Peijian, chief scientist of the Chang'e-3 program.
But checking and fixing the rover's errors is a job almost as complicated as designing and creating a new one, said Ye.
Pei Zhaoyu, spokesman for the lunar program, said that the abnormality came to researchers as a surprise.
"But worry alone solves no problem and we have to work out a solution," he said.
Most of the program's researchers gave up their Spring Festival holidays, which coincided with the robot's second dormancy, to spot causes of the problem and work out solutions for any possible situation, Pei said.
Pei said that the robot's second awakening was good news that far exceeded their worst preparations.
Now with another surprising wake-up, people 380,000 kilometers away on Earth are expecting more miracles from the robotic rabbit.
"Big fortune follows a hair-width escape from death," wrote Weibo user Yuyinniaoniao, citing a Chinese saying. "Just follow the example of your 'sister' Chang'e-2 and live longer."
Though its moon adventure is only a one-way journey, and the robot may end up as space trash, one Weibo user imagined another scene:
"One year later, the little guy from Chang'e-5 mission came, passing by my body which was covered with lunar dust. I sighed. How cold it is during the lunar night! Ten years later, I saw the five-star red flag on the spacesuit, and I was picked up. I was going home," wrote user Kevin-Ji Xuetao, replying to a post under the "Yutu Lunar Rover" microblog.
"One hundred years later, I heard a kid ask his mum, 'Is it the moon rover Yutu?' There I was, showcased in a museum, watching my peers explore farther and farther in space."