Under the influence of solar flares, from the night of May 10 to the early morning of May 11, the earth also erupted in a very geomagnetic storm (kp=9).
When the megamagnetic storm erupts, there are very brilliant auroras in many areas, and in addition, spacecraft operating in low-earth orbit are also affected. At that time, a NASA satellite of the United States was unexpectedly rotated due to the attenuation of the orbital altitude, and finally the satellite entered the "safe mode".
Because there is still thin air in low-Earth orbit, when the geodetic storm phenomenon erupts, the atmosphere will spread outward, which will increase the density of air in low-earth orbit and cause spacecraft to face greater air resistance during orbit around the Earth.
In such a situation, the flight speed of the spacecraft will decrease, which will lead to the attenuation of the spacecraft's flight trajectory. Many spacecraft, including the Chinese space station and the International Space Station, have dropped their flight orbits, but you don't need to worry, this is to be expected, and we have ways to deal with it.
Not long after the phenomenon of megamagnetic storms ended, news of solar flares has arrived. According to the information released by the Space Environment Research and Forecasting Center of the Chinese Academy of Sciences, on May 15, the sun broke out again with three X-class flares, the strongest of which reached X8.7, which was the strongest flare in the 25th solar activity cycle and reached the orange alert level.
The energy level of a solar flare is divided into five levels: A, B, C, M, and X, and the energy released increases by 10 times, among which the intensity of the X-class solar flare is the strongest, and the energy released by an X-class solar flare is almost equivalent to the energy released by the simultaneous explosion of billions of giant hydrogen bombs.
In X-class solar flares, the energy of X1 to X9 also increases step by step, taking the X8.7 solar flare that erupted this time as an example, its energy is almost 10,000 times that of X5 solar flares.
From these data, it can be seen that as the strongest flare in the 25th solar cycle, the energy of the X8.7 solar flare that erupted this time can be imagined.
A solar flare erupted a few days ago caused a very geomagnetic storm to erupt on the earth, and now the strongest flare in more than 10 years has erupted, will the earth be in danger? Although the solar flare was very powerful, it happened to be at night on the continent, so it had little impact on the ionosphere of the continent.
Nowadays, solar activity is very frequent, and although the eruption of solar flares sometimes does not affect the ionosphere above us, it will still have a certain impact on spacecraft operating in low-earth orbit, because these spacecraft fly very fast, basically flying around the earth every 1.5 hours.
As for how much the spacecraft is affected, it is actually related to the intensity of the solar flare. In 2003, that is, the 23rd solar peak year, the sun once erupted a flare that reached the X40+ level, when the energy of the solar flare was quite amazing, and the power was almost equivalent to the simultaneous explosion of 450 billion hydrogen bombs, which once caused the global short-wave communication interruption, over-the-horizon radar and civil aviation communication were also interrupted, and the impact range was quite large.
The Sun is now at the peak of its 25th solar cycle, and this year's January to October is the "maximum" of solar activity, which will reach its peak this year. This means that solar flares of various intensities are likely to continue in the next few months of the year. However, some experts predict that solar activity is not expected to be stronger this year than in 2003.
Seeing that solar flares have occurred frequently this year, and there may continue to be solar flares in the next period of time, the outbreak of these solar flares will affect the operation of spacecraft, and some netizens may be worried about the Chinese space station operating in low-earth orbit. Because there are now three astronauts from the Shenzhou-18 mission in China's space station, the spacecraft has been launched for 20 days, and it is expected that it will take more than 5 months to return to Earth after the mission.
If solar flare activity is still relatively frequent in the next period of time, it means that our space stations, spacecraft and other spacecraft will continue to be affected by these solar flares. Will the spacecraft in orbit have an accelerated attenuation of orbital altitude due to frequent eruptions of solar flares, and then enter the atmosphere?
We also mentioned why solar activity affects the operation of spacecraft, so you don't need to worry about it. Because our space station is more than capable of coping with these problems.
The design life of China's space station is more than 10 years or even longer, and the solar activity cycle is about 11 years, which means that we have long expected that the space station will continue to encounter solar activity during operation, so at the beginning of the design and manufacture of the space station, the design was carried out.
For example, there are many areas in our space station that are well shielded from radiation, and when there are frequent bursts of solar activity, we will detect and warn in advance, during which astronauts will not go out of the capsule.
If necessary, astronauts will enter areas with better radiation shielding. When the geomagnetic storm broke out a few days ago, the seven astronauts on the International Space Station were moved to an area with better radiation shielding.
In order to cope with the impact of solar activity, in addition to enhancing the radiation shielding ability of the space station assembly, it can also offset the problem of orbit attenuation by changing orbits. The orbital attenuation of space stations, spacecraft, and satellites is actually a normal phenomenon, and even without the influence of solar activity, the flight altitude of these spacecraft will continue to decrease.
As mentioned earlier, there is still rarefied air in low Earth orbit, which means that air resistance is impossible to ignore. Under the action of small air resistance, the flight speed and altitude of a long-running spacecraft will gradually decay, and finally fall into the atmosphere.
Therefore, the orbital attenuation of the space station is also expected, when the solar activity affects the flight altitude of the space station assembly, we can start the engine to accelerate the space station assembly and increase the flight orbit altitude, so as to prevent the space station from falling into the atmosphere.
In the event of an emergency, astronauts can also return to Earth directly from the space station assembly in a spacecraft. After entering the era of the space station, our manned spacecraft began to adopt the mode of "sending one to prepare one", and if there is a manned spacecraft in the Chinese space station to carry out a flight mission, there will be a new spacecraft on the ground in a state of standby.
It is the Shenzhou-18 spacecraft that is now on mission in the Chinese space station, so it is the Shenzhou-19 spacecraft that is on standby. If the spacecraft and space station are seriously threatened, and the astronauts urgently need to return to Earth from the space station, the Shenzhou-19 spacecraft on standby will be launched in the shortest possible time to carry out rescue missions.
Of course, spacecraft need to consume a lot of fuel in the process of orbit change, which is why those satellites cannot change orbit frequently, after all, the fuel carried by those satellites is very limited, and they will run out of fuel after multiple orbit changes.
The situation of the space station is different, orbit change and orbit lifting are the normal operations of the space station assembly, the space station assembly may change orbit before the spacecraft is launched and returned, and the space station assembly will also change orbit in the case of orbit attenuation, and the space station also needs to change orbit when avoiding space junk. Therefore, the long-term operation of the space station complex requires a large amount of fuel, which can be replenished by launching cargo spacecraft.
Why hasn't Tianzhou-8 been launched yet?
Friends who pay attention to China's manned spaceflight will find that in the early stage of the space station era, we will launch a Tianzhou cargo spacecraft in advance before each launch of a manned spacecraft, for example, before the launch of the Shenzhou 12 spacecraft, we will launch the Tianzhou-2 cargo spacecraft to send materials to the Chinese space station in advance.
This launch pattern continued until the Shenzhou-16 mission, and before the launch of the Shenzhou-16 spacecraft, we also launched the Tianzhou-6 cargo spacecraft in advance. But when the Shenzhou-17 spacecraft was launched, the situation changed.
Starting with the Shenzhou 17 spacecraft, we no longer continue to use the mode of launching a Tianzhou cargo spacecraft first and then launching the Shenzhou manned spacecraft. The Shenzhou-17 spacecraft was launched on December 26, 2023, while the Tianzhou-7 cargo spacecraft was launched on January 17, 2024, and on April 25, the Shenzhou-18 spacecraft was launched. What the hell is going on?
Before the advent of Tianzhou-6, we would launch 2 Tianzhou cargo spacecraft every year to resupply the space station assembly, but starting from the Tianzhou-6 cargo spacecraft, we will launch 3 Tianzhou cargo spacecraft every 2 years for replenishment. That is to say, every 2 years, the launch of 1 Tianzhou cargo spacecraft is reduced, but such an adjustment of the launch frequency will not affect the normal operation of China's space station, so you don't need to worry.
Because we have upgraded the Tianzhou cargo spacecraft, the Tianzhou-6 cargo spacecraft is the first spacecraft of the improved cargo spacecraft, and it is also the first cargo spacecraft produced in batches from Tianzhou-6 to 11, and the cargo capacity has been greatly improved compared with the previous Tianzhou cargo spacecraft.
The upgraded Tianzhou-6 cargo spacecraft has increased its cargo capacity from 6.9 tons to 7.4 tons, and its effective loading capacity has increased from 18.1 cubic meters to 22.5 cubic meters.
The upgraded Tianzhou-6 cargo spacecraft and Tianzhou-7 cargo spacecraft carry more materials and can support astronauts to fly in orbit for a longer time, so now the Shenzhou-18 spacecraft has been flying in orbit for more than half a month, and the Tianzhou-8 cargo spacecraft has not yet been launched.
Although the Tianzhou-8 cargo spacecraft has not yet been launched, the supplies of our space station are still very sufficient, and there is enough fuel for the space station to change orbit and lift the orbit, so you don't need to worry.