Beijing: Chinese scientists have claimed to develop methodologies for precise mapping of the Moon, including creating an accurate 3D models of lunar surface.
   
The Hong Kong Polytechnic University (PolyU) said that its surveying experts had successfully developed methodologies for precise mapping of the Moon, after intensive analysis of the data captured by the Chinese lunar orbiter ChangE-1 and other lunar exploration missions.
   
According to the PolyU, their efforts culminated in the development of a unique and innovative approach to the creation of accurate 3D models of the lunar surface, Chinese state-run Xinhua news agency reported.
   
The team has produced the most updated parameters of the lunar figure (the shape of the moon), which is essential for lunar mapping using 17.5 million laser altimetry measurements from the ChangE-1and the Japanese SELENE missions.
   
In addition, they also used the new topographic and gravity models to calculate improved crustal thickness and mass distribution of the Moon and established that the average thickness of the Moon's crust is about 40 kilometres on the near side and 50 kilometres on the far side.

It was introduced that the resulting lunar mapping was the hard work of a dedicated research team led by Professor Chen Yong-qi, Emeritus Professor of the Department of Land Surveying and Geo-Informatics, who is also serving on the Expert Committee of China's Lunar Exploration Programme (ECCLEP).
   
The other members of the team included Professor Chen Wu, Professor Ding Xiao-li, Professor Baki Iz, Bruce King, and Wu Bo, with all of them making concerted efforts for the success of the programme.
   
According to Chen Yong-qi, the lunar mapping project started in 2006.
   
The primary objective was to develop the methodologies and techniques for mapping the Moon surface, which is much more challenging than mapping the Earth's surface because of very few surveyed control points which are essential for accurate map making, Prof Chen Yong-qi said. Statistics showed that there were only fourteen lunar laser ranging retro reflectors (LRRR) and Apollo lunar surface experiment package (ALSEP) transmitter sites with accurately known coordinates available only on the near side of the Moon, installed by the US Apollo and former Soviet Union Luna missions in the 1960s.
   
Moreover, according to the team, the gravitational field of the Moon is not as well-known as that of Earth, which means the accuracy of the computed lunar satellite's position at any given time is lower than for Earth satellites, thus degrading the mapping accuracy and reliability.
   
In addition, the team expressed that highly reflective lunar surface created significant problems for the automatic processing of images to develop 3D models using the technique of photogramemtry, which is a widely used and highly reliable technique for the creation of maps and 3D models on Earth.
   
Furthermore, the team also revealed they had a plan to compare such data with other data sources in order to evaluate the performance of the ChangE mapping sensors.
   
Since Chen Yong-qi is serving on the ECCLEP, the team has direct access to more recent data captured by the ChangE satellite.

NASA launches twin satellites to map inner Moon

Meanwhile, NASA on Saturday launched a USD 500 million pair of washing-machine-sized satellites on a mission to map the Moon's inner core for the first time.
   
The twin spacecraft took off from Cape Canaveral Air Force Station in Florida on a three-month journey to the Moon at 9:08 am local time aboard a Delta II rocket.
   
"Liftoff of the Delta II with GRAIL, on a journey to the center of the moon," NASA commentator George Diller said upon blast-off of the GRAIL mission, which stands for Gravity Recovery and Interior Laboratory.
   
High upper level winds delayed the first launch attempt on Thursday, and also briefly set back Saturday's launch.

The duo will travel to the Moon for more than three months, arriving into a polar lunar orbit one after the other around New Year's Day.
   
With one spacecraft trailing the other, the plan is for the two to use gravity tools to map the terrain beneath, revealing the contents of the inner core of the Moon, about which little is known.
      
The mission should also shed light on the unexplored far side of the Moon, and perhaps tell scientists whether there was once a second Moon that fused with ours.
      
"GRAIL will be the first mission to determine the internal structure of the Moon," program scientist Bobby Fogel told reporters this week.
      
"We have used gravity science before to try to gain some insight as to what is going on inside the Moon, however these have been very primitive attempts.
      
"If those previous attempts could be likened to a magnifying glass, GRAIL by contrast would be a high-powered microscope."
      
Scientists believe that the Moon was formed when a planet-sized object crashed into the Earth, throwing off a load of material that eventually became what we now recognize as our planet's airless, desolate satellite.
      
How it heated up over time, creating a magma ocean that later crystallized, remains a mystery, despite 109 past missions to study the Moon since 1959, and the fact that 12
humans have walked on its surface.
      
A recent hypothesis that there may have been two Moons that slowly merged into each other can also be tested with this mission, said principal investigator Maria Zuber.
      
"If we want to reconstruct the evolution of the Moon over time, we certainly need to reconstruct the temperature structure of the Moon right now," she said.
      
Little is known for certain about what lies inside the Moon. The widely held belief that there is a small solid iron core surrounded by a liquid iron core is unproven, said Zuber.
 
(Agencies)