分类： science

For nearly 20 years, scientists have confirmed that water exists on the Moon — but critical questions remain unanswered. How much harvestable water ice is trapped in the Moon’s permanently shadowed polar craters, where sunlight has not touched the surface for billions of years? How deep is this ice buried, and what physical form does it take? These are the mysteries China’s upcoming Chang’e-7 lunar mission aims to solve, as the world enters a new era of lunar exploration focused not just on reaching the Moon, but unlocking its resources for long-term human activity.

Exploring these permanently shadowed craters is no small feat. Tucked at the base of deep, uneven craters near the lunar south pole, these regions sit at temperatures well below -200°C, cut off from sunlight and unreachable for most conventional exploration craft. Yet they are also among the most valuable real estate on the Moon: if the water ice they hold can be accessed and processed, it could provide drinking water, oxygen, and rocket fuel for future crewed missions and permanent lunar outposts.

The journey to this point stretches back more than six decades, starting when the Soviet Union’s Luna-1 became the first probe to reach the Moon’s vicinity in 1959. Early lunar exploration centered on simply reaching the celestial body; today, the core challenge has shifted to navigating and studying the most extreme, hard-to-reach lunar environments, and determining whether the Moon can supply the resources future explorers will need. China has built its incremental, ambitious lunar exploration program — named for Chang’e, the ancient Chinese goddess of the Moon — over the past 20 years, and Chang’e-7 represents the next bold step in that roadmap.

Scheduled for launch later this month, the mission’s timeline carries minor uncertainty following a recent failure of an unrelated Chinese rocket, but preparations remain largely on track. Unlike previous missions, Chang’e-7 uses an innovative multi-component design: it comprises an orbiter, a lander, a wheeled rover, and a revolutionary hopping craft that will act as the mission’s centerpiece. The Queqiao-2 lunar relay satellite, launched separately in March 2024, is already in position to support the mission, having previously served the successful Chang’e-6 sample return mission. Queqiao-2 will maintain steady communications between the exploration craft on the lunar surface and mission control on Earth.

While a final landing site has not been officially announced, the leading candidate is a sunlit ridge on or near Shackleton Crater, one of the most prominent permanently shadowed impact structures in the Moon’s south polar Aitken Basin. From this landing zone, the mission’s hopper will undertake the core exploratory work: unlike wheeled rovers, which cannot navigate the steep, broken crater walls that lead into permanently shadowed regions, the hopper is engineered to leap over treacherous terrain and descend into the dark craters that have remained undisturbed for billions of years. This design addresses the key challenges of steep slopes, permanent darkness, fragmented ground, and the need for autonomous navigation in the harsh polar environment.

Notably, Chang’e-7’s team is not searching for new evidence of water — scientists already have overwhelming confirmation of lunar polar water. Instead, the mission’s core objective is to characterize the existing water: map its exact distribution, determine its concentration and physical form, and assess whether it can be practically extracted for future use. This mission marks a key turning point for lunar exploration, shifting from mere discovery to evaluating the viability of in-situ resource utilization.

Other global space powers share the same long-term goal of establishing sustained lunar operations, but are pursuing different approaches to solve the same challenges. NASA, the United States’ space agency, has moved away from the traditional centralized state-led mission model in favor of its Commercial Lunar Payload Services (CLPS) initiative, which seeks to build a commercial lunar marketplace. NASA contracts private companies that own and operate their own spacecraft to deliver payloads and provide mobility and research services, and currently has 17 contracted deliveries carrying more than 60 scientific instruments.

NASA’s commercial approach has already produced early lessons: Intuitive Machines’ Athena mission (IM-2) undertook remarkably similar objectives to Chang’e-7, carrying a drill, a mass spectrometer to search for volatile compounds including water, a small hopping exploration craft, and an experimental mobile communications network. However, the mission ended prematurely when the lander tipped over at its landing site and powered down just one day after arrival. This contrast highlights that while both programs target the same critical lunar science questions, they are testing distinct strategic models to overcome the shared challenges of polar exploration.

Chang’e-7 is only the next step in a longer roadmap for lunar development. Following this mission, China plans to launch Chang’e-8 as early as 2028, which will focus on demonstrating practical technologies to utilize lunar resources. Down the line, crewed missions are expected to follow, leading to the construction of the International Lunar Research Station, a joint project between the China National Space Administration and Russia’s Roscosmos. On the U.S. side, CLPS will feed technological and scientific data into NASA’s larger Artemis Program, which is explicitly designed to lay the groundwork for long-term sustained lunar exploration.

At the end of the day, the extreme environment of the lunar south pole does not differentiate between programs or nations. Any craft exploring its permanently shadowed craters must contend with the same unforgiving conditions: total darkness, crippling cold, fragmented terrain, and significant communications hurdles. Reaching the Moon was one of the defining technological challenges of the 20th century. Mastering how to live and operate sustainably on its surface will go down as one of the great challenges of the 21st century — and Chang’e-7 is set to mark a major step forward in that global effort.

In an unexpected announcement made on Sunday, China has confirmed the postponement of its highly anticipated Chang’e-7 lunar mission, a groundbreaking expedition designed to hunt for water ice and conduct extensive surveys of the moon’s southern polar region. The robotic spacecraft, which forms the seventh installment of China’s expanding Chang’e lunar exploration program, was originally scheduled to launch within days from the Wenchang Space Launch Center located on the southern island province of Hainan. The China National Space Administration (CNSA) stated in a concise official statement that the mission currently fails to meet required launch conditions, meaning it cannot proceed within the pre-scheduled launch window for 2025. The postponement decision was reached after a comprehensive technical review, with the space agency noting that the call aligns with its core guiding principles of prudence, reliability, and a commitment to ensuring absolute mission success. No further details regarding the specific technical issues or the revised launch timeline have been released to the public at this time. Over the past several weeks, launch teams at the Wenchang facility had been conducting final pre-launch preparations for the mission, which was billed as a major step forward in China’s lunar exploration ambitions. Prior to the postponement announcement, China’s official state news agency Xinhua had outlined the mission’s far-reaching scientific objectives. Beyond its primary goal of detecting and mapping water ice deposits in the moon’s permanently shadowed polar craters, Chang’e-7 was tasked with carrying out comprehensive surveys of the lunar south pole’s surface environment and natural resource potential. The mission was also expected to deliver major breakthroughs in several key lunar exploration technologies, including precision landing, rover mobility, and deep space remote sensing. China’s Chang’e lunar program takes its name from the legendary moon goddess of Chinese mythology. The program has achieved a string of historic milestones in recent years, most recently the 2024 return of the Chang’e-6 probe, which brought the first ever samples of rock and soil collected from the far side of the moon back to Earth — a feat no other space program had accomplished before.

For decades, astronomers and astrophysicists have grappled with one of the most counterintuitive puzzles in solar science: why does the Sun’s outermost atmospheric layer, the corona, reach temperatures of millions of degrees Celsius—far hotter than the star’s visible surface, the photosphere? This stark temperature gradient across solar layers outright defies established thermodynamic logic, and until now, scientists have never been able to definitively quantify what drives the corona’s extreme heat and ability to replenish energy after massive eruptions.

New groundbreaking research from India, based on data collected by the country’s landmark Aditya-L1 space solar observatory, has brought the global scientific community closer than ever to solving this enduring mystery. In a new paper published in the peer-reviewed *Astrophysical Journal Letters*, a team led by leading solar astrophysicist Professor R Ramesh of the Indian Institute of Astrophysics (IIA) presents the first quantified breakdown of the two leading energy mechanisms thought to sustain the corona’s heat, revealing that magnetic field reconnection is responsible for nearly all of the layer’s energy replenishment.

To put the sun’s unusual temperature structure in context: the Sun generates all of its energy via nuclear fusion in its dense, superheated core, which hits roughly 15 million degrees Celsius. Moving outward from the core to the Sun’s visible photosphere, temperatures drop dramatically to around 5,500 degrees Celsius. Intuitively, temperatures should continue to fall as one moves further from the energy-producing core—but the opposite happens in the corona, where temperatures skyrocket back to between 2 million and 40 million degrees Celsius.

This anomaly becomes even more puzzling when accounting for the extreme energy the corona regularly sheds. The corona is the birthplace of catastrophic solar events including solar flares and coronal mass ejections (CMEs): massive expulsions of magnetized plasma and energy that the Sun launches into interplanetary space. While these ejections create striking auroras near Earth’s polar regions, they also pose serious risks to modern infrastructure, triggering geomagnetic storms that can disrupt satellite communications, interfere with GPS signals, and even bring down entire power grids.

During quiet periods of solar activity, the Sun produces between two and three CMEs per day. At the peak of its 11-year activity cycle, that number jumps to 10 or more CMEs daily. If the corona could not replenish the energy it loses during these frequent eruptions, the Sun would quickly cool, and Earth would be plunged into an irreversible deep freeze—an outcome that has never occurred, proving a powerful energy replenishment mechanism must be at work.

For years, scientists have hypothesized two primary processes that could supply the corona with energy. The first suggests that churning, convection-driven motions on the Sun’s surface generate energy-carrying waves that travel outward to the corona, much like ocean waves carry energy toward a shoreline. The second explanation centers on the Sun’s tangled atmospheric magnetic field lines: these lines constantly snap apart and reconnect, a process that releases massive amounts of heat energy.

Professor Ramesh’s team was the first to quantify the exact contribution of each mechanism, using high-resolution observations of an extremely energetic CME that occurred on August 5, 2024, captured by Aditya-L1’s Visible Emission Line Coronagraph (Velc) instrument. The team tracked the corona’s recovery in the 10 hours following the eruption, observing how tangled magnetic field lines snapped during the CME, then reconnected and reverted to their original configuration to replenish the corona’s lost energy.

Their calculations revealed a stark divide: just 7% of the corona’s total energy requirement comes from surface-generated waves, while a full 93% is supplied by the repeated snapping and reconnection of solar magnetic field lines.

While surface motion waves do contribute some energy, the study confirms their input is far too small to sustain the corona’s extreme temperatures on their own. Professor Ramesh emphasized that magnetic reconnection occurring across the entire solar atmosphere is the undisputed primary driver of the corona’s anomalous heat.

These new quantified findings provide a critical benchmark for future solar research, bringing scientists closer to answering a fundamental physics question that has defied explanation for generations. As India’s first dedicated solar space mission, Aditya-L1 continues to deliver groundbreaking data that advances global understanding of our host star, with implications for space weather forecasting and fundamental astrophysics research.