The China National Space Administration reported on April 12 that the Queqiao-2 relay satellite, which was launched on March 20 this year, has completed the in-orbit communication test, and the mission has been a complete success. In 2018, the original Queqiao was launched, and now the Queqiao No. 2 is "new", let's find out!
Why launch the Queqiao series of relay satellites?
Because the earth could not communicate directly with the spacecraft on the far side of the moon, before Chang'e-4 went to the far side of the moon, it was necessary to send a relay satellite to the designated location to build a "bridge" for communication between the earth and the moon.
This "bridge" is the Queqiao relay satellite, which spreads its "big umbrella" antenna to help the probe "communicate" with the Earth and provide communication services for Chang'e-4, which is working on the far side of the moon.
With the Queqiao, why do you need to erect a new "Queqiao" on the earth?
Queqiao No. 2 is an upgraded version of Queqiao, Queqiao has a design life of 5 years, and is currently in overdue service, and Queqiao No. 2 has a design life of 8 years.
The fourth phase of the lunar exploration project is mainly aimed at the south pole of the moon and the far side of the moon, and the Queqiao orbits around the Earth-Moon Lagrange L2 point, mainly focusing on the far side of the moon, and the south pole of the moon is too far away for the Queqiao, so the Queqiao-2 was dispatched, and its work focuses on covering the south pole of the moon.
After the departure of Queqiao-2, it will carry out its work in two stages, first of all, it will run for a period of time in a large elliptical frozen orbit around the moon with a period of 24 hours. Then, Queqiao-2 will change orbit into a 12-hour circumlunar large elliptical frozen orbit.
In these two orbits, a oscillating equilibrium point of the Earth's gravitational action was found, so that the spacecraft could operate stably for a long time without consuming too much propellant, so it was called "frozen orbit".
When performing the task of "conveying affection", the two generations of Queqiao adopted the "regeneration and forwarding" mode. Not only can he "pass notes" with his left hand in and out with his right hand, but he can also "write letters on his behalf". The "regeneration and forwarding" mode of Queqiao-2 can also support the coordination of multiple exploration missions at the same time.
Teach you a trick: distinguish two generations of "Magpie Bridge" at a glance
Behind the Queqiao's "big umbrella" antenna are three "braids", which are low-frequency radio antennas used for scientific observations. The corresponding position of Queqiao No. 2 has changed from three braids to one, with a "small pot".
Since Queqiao-2 is working in orbit around the moon, in order to always maintain a signal pointing at the earth and the moon at the same time, in addition to the "big umbrella" antenna pointing to the moon, it also needs a "small pot" antenna to point at the earth, and the "small pot" relies on that "braid" to constantly adjust its direction in the process of orbiting around the moon and maintain real-time communication with the earth.
Compared with the Queqiao, the Queqiao-2 is larger, more difficult to develop, has more functions, and has a larger mission time span, and also bears more important responsibilities. It will provide relay communication services for Chang'e-6, which is about to "dig in the ground" on the far side of the moon, and Chang'e-7 and Chang'e-8, which are building the basic models of the international lunar scientific research station. At the same time, scientific exploration missions such as magnetotail observation will be carried out simultaneously.
Let's look forward to the new message of Queqiao to unveil more mysteries on the far side of the moon for us.
Source: Xinhua News Agency