On the morning of April 15, 2022, Astrophysicist Jonathan McDowell of the Harvard-Smithsonian Center for Astrophysics published a tweet saying that a Chinese satellite that lost control after launching in September 2021 has now miraculously appeared in a rare Monya orbit, which is also the first time a Chinese satellite has appeared in this orbit!
And about this mysterious Monya orbit and the mysterious Chinese satellite, what is it? Maybe many people don't know? At the same time, it is not clear why the satellite can appear in the mysterious orbit again after it is out of control, which is worth speculating.
What is the mysterious Monya Orbit?
Speaking of satellite orbits, familiar people may talk about their familiar geostationary orbit, Earth transfer orbit, geosynchronous orbit, etc., but many people may be hearing about the Monia orbit for the first time. In fact, the emergence of the Monya orbit, it is necessary to start from the early days of the Cold War, with the successful launch of artificial satellites by the Soviet Union, and the application of them to military struggles and space hegemony, although the Soviet Union launched a lot of artificial satellites for monitoring the strategic defense of the United States and its own country, especially in the geostationary orbit only need three satellites distribution, it can achieve the whole strategic early warning monitoring of the region, so the countries that began to try satellites for strategic anti-missile will be in geostationary orbit as the first choice for their own strategic anti-missile. However, for the Soviet Union located in the high latitude region, although the field of view of the geostationary orbit is wider, but also because of the greater impact of the satellite's tilt angle, in addition to the satellite itself needs greater transmission power, and because of the greater impact of the angle of incidence in the atmosphere, even if the satellite can pass over the high latitude area, the stay time is very short, and it is impossible to achieve the whole strategic early warning monitoring.
Therefore, the Soviet Union deliberately designed a special satellite orbit in the 60s of the last century, which is a special orbit with an inclination of 50--65 degrees, and its apogee is not only slower, making it stay longer, and because its apogee is just above 50-63 degrees north latitude, and the altitude reaches 40,000 kilometers, so for high-latitude countries such as the Soviet Union, this special satellite orbit, compared with the geostationary orbit, is more suitable for deploying early warning satellites for strategic anti-missile. This special satellite orbit is also famous for the "lightning" strategic early warning satellite launched by the Soviet Union, so it is also known as the "lightning orbit" and the "Monya orbit".
The mona orbit is not orbiting the earth's elliptical, but vertically in the direction of longitude, somewhat similar to the polar orbit, but the biggest advantage over the polar orbit is that its perigee is in the deserted Antarctic Earth, and because the perigee is affected by the earth's gravitational speed is very fast, but the apogee will pass through most of the northern latitudes, especially over high-latitude countries like the Soviet Union, and because it is far from the earth, it runs slower and the time for monitoring high latitudes for a long time is also longer. Therefore, in addition to being used for strategic early warning and monitoring, this Monia orbit can also be used for satellites such as earth communications and broadcasting that need to cover a certain area for a long time.
At the same time, this satellite orbit is also because of its high latitude, so that when countries in high latitudes launch satellites into this orbit, because they no longer need to launch in the equatorial direction like the geostationary/transfer orbit, so the rocket consumes less fuel, the rocket launch success rate is higher, and the rocket launch cost is lower, and it begins to be favored by more and more countries with high-orbit launch capabilities.
On September 27, 2021, the "Test 10" satellite launched by the mainland with the Long March 3B carrier rocket at the Xichang Satellite Launch Center, as a verification platform for the mainland's new satellite technology, its initial plan is to fly to the Monia orbit, laying the foundation for the subsequent mainland to launch more communication, navigation and early warning satellites in this orbit. However, after the satellite launch, due to the early separation time of the satellite and arrow, the perigee height of the test 10 satellite is low, and it is very easy to be disturbed by the atmosphere when passing through the perigee and reduce the orbital altitude, so although the test 10 satellite is successful in separating the star arrow, it is a pity that the satellite did not enter the predetermined orbit and the launch was declared unsuccessful.
However, from the satellite orbit parameters released by Harvard astrologers, when the satellite was launched into orbit in October last year, its satellite orbit parameters were only 177 kilometers perigee, 40,104 kilometers apogee, and the orbital inclination was only 51 degrees, compared with the parameters of the Monia orbit standard, although the apogee and inclination were appropriate, the perigee height difference was nearly 10 times, so it was reasonable to announce the launch failure. However, today, the orbit parameters of the satellite have become 40,092 kilometers apogee, an inclination angle of 51 degrees, and a perigee of 1,106 kilometers, which proves that the satellite has correctly returned to the predetermined orbital range of Monia by modifying the orbit parameters at this stage.
So how did the satellite gradually climb from a lost orbit of only 177 km perigee to a predetermined orbit of 1106 km perigee?
In the past, satellite orbit change mainly relied on the rocket engine it carried to implement orbit change maneuvers, but because the satellite's own fuel is limited, a small range of maneuverable orbit changes can be satisfied, but large-distance orbit change maneuvers cannot be realized at all, so once the satellite enters the orbit parameters and the predetermined orbit parameters are quite different, it will directly declare the launch failure.
However, with the successful application of the Hall thruster using electric energy propulsion, because the Hall thruster is to continuously accelerate the electrical energy generated by the satellite solar sail panels, the thrust is used for satellite maneuvering orbit change needs, so the test 10 satellite, as a test nature, is likely to rely on its own Hall electric thruster to continuously accelerate the orbit change and return to the predetermined orbit.
As for why the altitude of less than 800 kilometers, the satellite orbit change operation took less than half a year? This is also because although the Hall thruster jets electric ions very fast, but its thrust is very small, at this stage even the most advanced Hall thruster in the world, its maximum thrust can only blow up a piece of A4 paper, so for several tons of satellites, it can only gradually improve the orbit through continuous long-term acceleration.
However, also because the Hall thruster does not rely on satellite fuel at all, and can continue to work for a long time, so the thrust is small, but it is very suitable for maintaining the orbital height of the satellite, so more and more low-Earth orbit spacecraft have used hall thrusters as daily orbit-setting thrusters, like the core capsule of the Tiangong space station that the mainland is expected to complete this year, and 6 Hall thrusters independently developed by the mainland are installed for the maintenance of the usual orbital parameters. At the same time, with the successful return of the test 10 satellite to the predetermined orbit, it not only laid the foundation for the mainland to launch more satellites into the orbit, but also laid the foundation for the remediation, correction and more aerospace applications of the continental satellite orbit.