The risk associated with the impact was low… but China’s nonchalance over space debris continues to fuel its standoff with the United States.
On Sunday July 24, China carried out a new launch of its Long March 5 B rocket. Its mission: to transport a laboratory module to its space station currently under construction in Earth orbit. It was abandoned in orbit before crashing on our planet… which again caused many observers to talk, starting with the Americans.
Fortunately, this object of about 30 meters long did not crash into the ground as it was. The vast majority of the structure did not survive atmospheric re-entry, during which the structure is subjected to immense thermal stresses due to friction with the atmosphere. Most of the equipment (60 to 80% depending on the sources) burned during the descent.
An unpredictable impact zone
If this rather anecdotal event was followed so closely, it is because unlike American launchers, for example, the Long March 5B rocket is not capable of firing a second time once its engines have been turned off. This means that its operators cannot precisely control the drop.
Instead, they just drop it in an orbit they think is safe. Little by little, the friction generated by the few air particles in the upper atmosphere gradually slows down the carcass. She ends up passing a critical threshold before starting an uncontrolled fall.
Reentry looks to have been observed from Kuching in Sarawak, Malaysia. Debris would land downrange in northern Borneo, possibly Brunei. [corrected] https://t.co/sX6m1XMYoO
—Jonathan McDowell (@planet4589)
And it is this element that has aroused criticism, especially on the side of the Americans who never hesitate to comment on the slightest deeds and gestures of China. Because in this case, the part of the launcher that has not been vaporized during the descent can sometimes cause problems.
The many surviving pieces of debris usually end up crashing into a very wide area. In this case, it measured about 2000 km by 70 km. What is annoying is that for the reasons cited above, it is impossible to predict the exact location; we only know that the point of impact will be located somewhere below the final orbit of the vehicle.
In any case, this situation did not prevent Zhao Lijian from sleeping soundly. The spokesman for the Ministry of Foreign Affairs had contented himself with stating laconically that the risk for aviation and humans was “ very weak “.
Objek seperti tahi bintang kelihatan di langit beberapa kawasan di seluruh Sarawak sekitar jam 12.50 malam tadi.
Kredit: Haiqal Iskandar
— MALAYSIA MOST VIRALL (@MALAYSIAVIRALL)
A very low risk, but not negligible
Eventually, the craft crashed right into the Indian Ocean, between the Philippines and Malaysia; it did not cause any particular damage to human installations. This was the most likely outcome, as in absolute terms the risk associated with this debris remained relatively low. It was in any case the interpretation of several observers, such as analyst Ted Muelhaupt, quoted by Reuters. Taking into account the initial trajectory, he was able to estimate that 75% of the exposed surface was covered in water, jungle or desert.
In practice, a person is more likely to be struck by lightning than to be the victim of one of these spatial shrapnels. But the risk is still less abstract than Chinese officials admit, and this possibility could not be ruled out. According to other specialists consulted by Reuters, the probability of a problematic impact was greater than 1/1000. A completely significant figure, and well beyond the conventions to which aerospace players usually adhere.
Traditionally, the latter arrange so that this probability does not exceed 1/10,000. And overall, the whole industry is starting to perform very well on this point. Today, in the era of SpaceX and New Space, the challenge is no longer even to control the fall; it is a question of recovering almost all the parts of the launcher intact.
But despite its rapid progress in this area, China has yet to adopt this practice on a large scale. In fact, for the moment, it is even quite the opposite. And the country of Xi Jinping does not seem particularly concerned about the consequences of this debris for other countries.
The inhabitants of the small Ivorian town of N’Guessankro can testify to this. In May 2020, debris from another Long March 5B rocket fell straight on the village (see video below). The following year, an Indian village was treated to a comparable surprise.
An eminently political sticking point
Fortunately, these incidents caused no injuries. But they show that these are well-founded criticisms, and not gratuitous Sinophobic criticisms from the American camp. In this context, this uninhibited and phlegmatic positioning tends to irritate officials from other countries.
“ It is clear that China is failing to meet acceptable standards in terms of space debris “, railed Bill Nelson, the administrator of NASA, in a press release last year. “ It is fundamental that China and all other countries and commercial entities act responsibly and transparently in space to ensure the security, stability, and sustainability of space activities in the long term. “, he specified. He reiterated those comments in a tweet after the crash.
…reliable predictions of potential debris impact risk, especially for heavy-lift vehicles, like the Long March 5B, which carry a significant risk of loss of life and property.
Doing so is critical to the responsible use of space and to ensure the safety of people here on Earth.
— Bill Nelson (@SenBillNelson)
Let us remember all the same that despite this posture, Uncle Sam is not not free from all criticism at this level. In the past, many out-of-control launchers have crashed in this way under the guidance of NASA. Several Saturn rockets from the Apollo missions ended up like this. We can also cite the shuttle Columbia, even if the situation was quite different.
In recent years, with advances in technology, most countries have come a long way; today the majority atmospheric re-entry is controlled so that the crash does not represent any danger… but not on the side of China.
According to the list of astronomer Jonathan McDowell who monitors these phenomena (available), since 2020the only massive objects to have undergone an uncontrolled atmospheric re-entry were all flanked by the Chinese pavilion. It was each time a Long March 5 B rocket.
Remember that the Chinese and the Americans never miss an opportunity to address virulent criticism through diplomats; and right now the United States is regularly targeting Chinese aerospace. They accuse him in particular of orchestrating large-scale industrial espionage and of wanting to monopolize the Moon, which the Chinese contingent has vigorously denied.
We must therefore keep in mind that these statements are rarely 100% objective, on one side or the other. They are part of a great geopolitical showdown where the United States actively seeks to limit China’s influence, and vice versa; recently, the American Congress, for example, passed a law which unblocks $280 billion in funds. The claimed objective: “to counter China”.
The launch of the next Long March rocket is scheduled for October 2022 ; we therefore give you an appointment on this date which will probably be accompanied by new acerbic comments from both sides. In any case, it will be interesting to follow the evolution of this situation, at a time when the conquest of space continues to become more and more important in strategic, political and economic terms.