China launched relay satellite named Queqiao (Magpie Bridge) to establish communication link between earth and its planned Chang’e-4 lunar probe (rover) that will explore the dark side of moon. It was launched as part of Chinese Lunar Exploration Program (CLEP) onboard of Long March-4C rocket from Xichang launch centre.
Queqiao (Magpie Bridge)
Queqiao (meaning bridge of magpies) satellite will serve as communications relay for future Chang’e-4 rover that will explore in South Pole-Aitken Basin in moon’s far side. It will be situated in halo orbit i.e. Earth-moon Lagrange point L2, a gravitationally stable spot located 64,000 kilometers beyond lunar far side. It will be world’s first communication satellite operating in this location. It will help China to realise its goal of being first country to send probe to soft-land on and rove far side of the moon.
Need for relay Satellite
Moon is tidally locked to Earth, meaning it always shows same face (near side) to Earth. So, relay link is necessary to communicate with spacecraft on far side, which will otherwise have to send their signals through moon’s rocky bulk.
Chinese Lunar Exploration Program (CLEP) also known as Chang’e program after Chinese moon goddess Chang’e, is ongoing series of robotic Moon missions by conceived by China National Space Administration (CNSA). The program incorporates lunar orbiters, landers, rovers and sample return spacecraft, launched using Long March rockets. Under it, Chang’e 1 and Chang’e 2 probes already have reached lunar orbit in 2007 and 2010, respectively. The Chang’e 3 mission is in process to put lander and rover on moon’s near side. China is also planning to laugh Chang’e 5 T1, a mission to send sample-return capsule around moon and back to Earth to demonstrate technology needed to survive fiery atmospheric entry.