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Xinhua News Agency, Beijing, July 1st (Xinhua) - Breaking records continuously, decoding rocket launches with multiple stars and one arrow

Xinhua News Agency reporters Hu Zhe and Song Chen

Group buying and carpooling have become people's daily habits, and the launch of rockets has increasingly become a norm for satellite launches. With the continuous development of satellite technology in China, especially in the field of civilian satellites, the mode of mass launch of small satellites and constellation formation in space has gradually become mainstream. Recently, China's carrier rockets have continuously broken the record of successfully launching multiple satellites with one arrow. What is the launch mode of multiple satellites with one arrow?

At 12:10 on June 7th, the Lijian-1 YJ-2 carrier rocket was successfully launched into space from China's Jiuquan Satellite Launch Center, using a one rocket 26 satellite approach to successfully launch the test satellite into its designated orbit. Shen Jizhong

Satellite launches into the sky through a combination of rockets

At 12:10 am on June 7, 2023, the Lijian-1 YJ-2 carrier rocket was successfully launched from the Jiuquan Satellite Launch Center in China, using a 26 star one rocket approach to successfully launch the test satellite into its designated orbit.

At 13:30 on June 15, 2023, China successfully launched 41 satellites, including Jilin-1 High Resolution 06A, using the Long March-2D carrier rocket from the Taiyuan Satellite Launch Center. The satellites entered the designated orbit and the launch mission was a complete success.

Through a single launch mission, multiple satellites are sent to predetermined orbits - with the continuous breaking of records, the one arrow multiple satellite launch mode has attracted attention.

Taking the launch of 41 satellites with one arrow as an example, in order to accommodate these 41 satellites, the development team designed a 4-meter-high cylindrical section, and the 41 satellites were installed in a wall mounted manner and staggered. In addition to locating the positions of 41 satellites, the rocket also uses larger diameter fairings to ensure that all satellites safely reach their destinations.

During the separation process of satellites and arrows, a 7-layer satellite separation method was adopted in sequence. "It's like dividing a layer of stars, the rocket takes a step back, then divides another layer of stars, the rocket takes another step back, and finally divides all seven layers of satellites," said Li Jianqiang, chief designer of the Long March 2D carrier rocket at the Eighth Academy of Aerospace Science and Technology Group.

Li Jianqiang introduced that from the perspective of economy and overall timeliness, one arrow with multiple stars is the most effective, and only a very small number of countries internationally have mastered this technology.

Shooting multiple stars with one arrow poses multiple challenges

In rocket launch, it is a significant challenge to ensure that passengers of satellites with different sizes, functional characteristics, and appearance can safely sit and get off on time without experiencing motion sickness. To this end, aerospace technology workers have designed a series of ingenious solutions.

"To achieve one rocket with multiple satellites, multiple aspects need to cooperate." Ma Yuhai, deputy chief engineer of the Lijian 1 carrier rocket, told reporters that a large amount of calculations need to be carried out before rocket launch, and the relationship between various satellites needs to be analyzed through dynamic simulation to avoid the impact or influence of the environment on multiple satellites during rocket separation. After the launch of the rocket, precise control technology is involved, "just like stopping at a bus stop, the next batch of passengers arrive at one station."

"At the same time, our design should leave some margin to ensure that it can adapt to certain deviations and avoid collisions with each other." Ma Yuhai said for example, it's like when parking, you can't park while wiping, so the door won't open and you can't do anything else.

"In addition, the development team has carried out multiple batches of separation timing design and optimization to ensure the safety of far-field separation. The rocket attitude is adjusted between multiple batches of separation to ensure the safe distance of multiple satellites during in orbit operation. Regarding electromagnetic compatibility, ground compatibility tests have been conducted between satellites and with the participation of rockets." Ma Yuhai said.

It is understood that in the process of preparing for the launch of one rocket with multiple satellites, Lijian 1 carrier rocket, relying on the scientific research strength of the Chinese Academy of Sciences and the accumulation of a large number of advanced technologies, has achieved joint research in many fields such as mechanics and materials, standardized the development process, strengthened the construction of the quality system, broken through 6 major key technologies and 13 technologies that were first used in China, and enriched China's solid carrier rocket launch capability spectrum.

Expanding diversified and convenient space entry and exit capabilities

The White Paper on China's Aerospace in 2021 released by the State Council Information Office points out that China will continue to improve the comprehensive performance of its space transportation system and accelerate the upgrading and replacement of its launch vehicles.

The Long March-2D carrier rocket, which is carrying out the one arrow 41 star launch mission, is a veteran of the Chinese space launch vehicle family. The Long March 2D carrier rocket has set a record of 5 victories in 5 battles within 60 days, 4 launches from different launch sites within 40 days, and 15 launches in a year.

Experts introduce that after more than 30 years of continuous accumulation and innovation, the Long March 2D carrier rocket can now support various forms of launch needs such as single star, multi star parallel, series, and carrier. In the future, more possibilities will be explored to carry more new missions.

The execution of the 26 star launch mission is the second flight of the Lijian-1 carrier rocket, marking the continuous success of the Lijian-1 carrier rocket in terms of technological maturity and reliability improvement.

"In the future, we will also attempt rocket launches with larger fairings and conduct sea launch tests, while accelerating the development of liquid launch vehicles. In the long run, we will also make efforts in the development of reusable launch vehicles," said Ma Yuhai.