China's first interplanetary mission Tianwen 1 to Mars has completed its second anniversary but the country is silent on the status of the mission's Zhurong rover.
Zhurong was expected to wake up in December but Beijing and authorities have remained silent on the status of the rover, reports Space.com.
The rover does not carry a radioisotope heater unit, like other rovers including China's Yutu moon explorers.
It has a pair of "windows" allowing a chemical called n-undecane to store heat energy.
"Dust storms in Utopia Planitia may have impacted the rover's ability to generate heat and light. This could potentially be the issue explaining Zhurong's silence," the report said.
Both the Tianwen 1 orbiter and Zhurong rover have completed their primary missions.
Launched in July 2020, the mission's orbiter monitored the weather on Mars' southern hemisphere, while the six-wheel solar-powered Zhurong rover mapped the Red Planet since it landed and started operations in May 2021.
The rover, named Zhurong after the god of fire in Chinese mythology, entered hibernation on May 18 due to severe winter weather.
The probe transmitted about 1,040 gigabytes of raw data back to Earth, which will eventually be released for scientists around the world.
China is now aiming to beat NASA and ESA in returning Mars samples to Earth.
According to Sun Zezhou, chief designer of the Tianwen-1 Mars orbiter and rover mission, China plans for a two-launch profile, lifting off in late 2028 and delivering samples to Earth in July 2031.