At 11:06 on February 27, Wenchang Cosmodrome, Hainan.
After meticulous preparations, the Long March 8 Yao-2 rocket ignited and took off here, took off smoothly, and then successfully sent the 22 satellites lifted into the predetermined orbit, creating the highest record for the launch of multiple stars in one arrow on the mainland.
Long March 8 Yao-2 carrier rocket. Xinhua News Agency Photo by Tu Haichao
At Wuhan University (hereinafter referred to as "Wuhan University"), thousands of miles away from the Wenchang launch site, teachers and students of the Academy of Aerospace Science and Technology and the School of Remote Sensing Information Engineering were thrilled to see the live broadcast of the satellite entering a predetermined orbit - among the 22 satellites, there is a satellite called "Daystar", which was developed by the teachers and student team of the academy for three years.
Why do a bunch of teachers and students insist on launching satellites? Satellite development and launch, where does the high amount of money come from? How did a student-focused team accomplish this seemingly impossible task?
"Let the students do it!"
Professor Jin Guang, the person in charge of the "Daystar" project, was introduced to Wuhan University as a high-end talent in 2019. Professor Jin Guang has worked in the Changchun Institute of Optics of the Chinese Academy of Sciences for a long time, and is a leading figure in the research and development of optical remote sensing satellites in the mainland aerospace, and the famous "Jilin No. 1" is his space masterpiece.
According to him, the idea of developing "Daystar" actually originated from a student's thesis defense. In the defense, some students expressed a lot of new scientific research ideas, but they have been suffering from the lack of suitable data to study and verify, and most of the data that can be used is derived from the data released abroad, which does not meet the research needs.
This made Wu Zhaocong and Professor Jin Guang in the audience very emotional - if they have their own satellites, they only need to send a command to shoot immediately, and the next day they can send back the required data. The two professors summed up, since the team already has the strength to develop, why not raise their own funds to design, manufacture and launch their own satellites?
The Daystar team is conducting research and development discussions
In this way, the concept of the "Daystar" project was conceived.
For the implementation of the project, Professor Jin Guang took out 5 million yuan from the 10 million yuan of scientific research start-up funds given by the school as satellite research and development expenses. "Wuhan is an important base for China's aerospace industry, and it has not yet had its own satellite payload, so I always feel that something is missing, and I want to use this money to contribute a little bit of my own meager effort." In addition, Professor Jin Guang took out 3 million yuan from the scientific research fund as the launch cost.
A satellite cost 8 million yuan, in Professor Jin Guang's view, whether it is developed or launched, it is very scratchable. But after the funds are in place, where does the satellite development team come from?
"Let the students do it!" Professor Jin Guang's proposal is shocking, but he has his own considerations - the students are energetic and curious, and when the satellite is successfully developed, the students will cultivate talents!
What is less well known is that when Professor Jin Guang presided over the development of "Jilin No. 1" at the Changchun Institute of Optics of the Chinese Academy of Sciences, he also took the student team as the main body. "On the world's authoritative subject rankings, Wuhan University's remote sensing science and technology has been rated as the world's first for many years, and it is certainly no problem for students to do it!"
In this way, the teachers of the remote sensing discipline of Wuhan University have a consensus - the development of "Daystar" should also let students take the lead, use the satellite as a new teaching platform, and put the laboratory in the sky, so that students can design and complete experiments in space through real-time interaction with satellites, and teachers and students can obtain data through it to verify no matter what whimsy they have.
"There are many colleges and universities across the country that 'play' with robots, but very few can 'play' satellites, and the concept proposed by Wuhan University can be said to be the first of the country's colleges and universities." Professor Jin Guang said.
In April 2019, the "Recruitment" poster of the "Daystar" project was posted on the campus of Wuhan University - whether undergraduates, master's students, doctoral students, all those who are willing to engage in aerospace careers and have enthusiasm for developing satellites can apply, and the more different disciplines, the better.
The teaching team carefully evaluates the preliminary list, and finally determines the official list after considering the professional background of different disciplines. Satellite development is generally divided into mechanical, thermal control, attitude control, star affairs, communications, power and other major systems, the screened out of the "Daystar" student team is also divided into a number of R & D groups according to these systems, from the development, control, management to the later application of four links, truly closed loop.
In the more than three years from the idea to the completion of the development, some students graduated and left, and some students joined in the relay, and there were more than 50 students who participated in the development of "Daystar", including about 20 undergraduates. The student team truly constitutes the main force of the research and development of "Daystar"!
Professor Jin Guang said that the development of satellites with students as the main body can not only enhance students' knowledge and technology, cultivate students' sense of mission and pride, but also enable satellites to walk off the altar from then on. According to Professor Jin Guang's vision, in the future, in addition to serving the scientific research of martial arts masters and students, "Daystar" will also provide free sharing of data for all universities and research institutes around the world.
"The real hero is the teacher behind it"
"Although our team is based on students, the real heroes are the teachers behind them, and the technical support forces are led by teachers." Zhou Hao, a master's student at the School of Remote Sensing and Information Engineering of Wuhan University, told the "China Youth" reporter that the words revealed the steadfastness and humility of the scholars, "From thinking about what work to do on the satellite, to what parts need to be used, it is Teacher Jin Guang who takes us to do it." ”
In September 2019, Zhou Hao joined Mao Qingzhou's mentor team and chose photogrammetry and remote sensing. "When the 'Daystar' program was first established, I was a senior in college, and I was already working with Teacher Mao at that time, which can be said to be the first batch to come in." Zhou Hao still remembers the scene of the first meeting — there were more than a dozen people, most of whom were undergraduates.
In the "Daystar" research and development team, Zhou Hao is mainly responsible for satellite sensor integration and testing, which focuses on the later stage of checks, leaving them with the least time to correct errors.
The sun windsurfing board can't be opened! When Zhou Hao assisted the teacher in the final assembly test at the Wenchang Satellite Launch Base, there was an accident.
Professor Jin Guang at work
"At that time, when testing the separation of star arrows in the laboratory, there was no problem." Teacher Wang Shaoju said, "Has Chacha made any adjustments in the period from February to Wenchang? ”
Under the leadership of teacher Wang Shaoju, everyone divided labor and cooperated, and finally found the problem: in terms of software, the code in the star control system was logically conflicted due to the later modification, causing some of the codes separated by the star and arrow to be logically conflicted; in terms of hardware, due to the problem of assembly techniques, the spring used for the ejection of the solar sail board was stuck by the bolt.
Find the problem, and you will succeed for a long time. Everyone immediately began to work on the repair work at the Wenchang Satellite Launch Base, from optimizing the code to contacting the supplier, and in less than two days, the problem was fully solved.
"If you can't get on the rocket this time, you don't know when to wait next time." Because as far as I know, the satellites carrying the latter phases of the rocket are already lined up. Zhou Hao sighed, "There is no danger, but I still want to thank the teachers of the team!" ”
"This experience
Taught me to think differently."
"I was lucky enough to be able to turn my scientific research results from paper to physical objects during my time at school, not to mention the heavens." Guo Yuxuan, a ph.D. student majoring in remote sensing science and technology at Wuhan University's School of Remote Sensing and Information Engineering, couldn't help but repeat it again, "I am really lucky!" ”
Guo Yuxuan has been engaged in satellite image processing during her master's degree, and when she was studying for her doctorate, she took the initiative to contact Professor Jin Guang, became his student, and gloriously joined the "Daystar" research and development team.
Team members are working on research and development
"We need to materialize the results of our research." This is a sentence that Professor Jin Guang often says to the team students, but in the process of transition from software to hardware, Guo Yuxuan admits that it is not smooth.
"The number of pixels in an image does not change, and the image resolution does not change in theory." Regarding the question of whether the resolution decreases when the camera sensor CCD acquires images for color reproduction, based on the research basis of image processing during the master's degree, Guo Yuxuan and the tutor have a fierce discussion.
"You can try to quantify the energy lost in the color restoration process from an optical point of view, combined with the modulation transfer function, maybe this is a new idea." Professor Jin Guang proposed another possibility. This discussion woke up Guo Yuxuan, but being exposed to the complex field of optics was a new beginning for her.
"Learn!" Guo Yuxuan, who has always refused to accept defeat, also did not flinch this time, and she began to collect and organize materials and learn about optical sensors. After combining the field of optics with the field of image, Guo Yuxuan found that the intersection of disciplines will indeed bring a broader thinking and perspective, and she also understands the height of the tutor more and more.
"This experience taught me not to limit myself to my profession, and only by thinking about problems from different angles can I put forward more profound insights from a higher perspective." Guo Yuxuan said with deep feeling, "This is the profound inspiration I received during the discussion with the mentor, and it is also the valuable knowledge I learned in the 'Daystar' development team." ”
"I have personally experienced what is the 'Chinese Aerospace Spirit'"
As the only student at Wuhan University to participate in the launch mission at the base site, Song Yufei, a second-year master's student in the School of Remote Sensing And Information Engineering of Wuhan University, said with a smile: "This is completely a coincidence. ”
At the beginning of 2021, Song Yufei officially became a member of the development team of "Daystar".
On February 13, after the "Daystar" development team completed all the work of satellite testing and star arrow docking at the Wenchang Satellite Launch Base, because there was still a 14-day gap period before the satellite launch, the team decided to leave Song Yufei alone as a representative of the base under comprehensive consideration, responsible for communicating with the launch site.
"After so many days at the launch site, I have personally experienced what is called 'China's aerospace spirit.'" In dealing with the staff of the base, Song Yufei was extremely impressed by their attitude of carefully considering and repeatedly discussing every detail, "The 'special' that can tackle key problems should be reflected here." ”
"Daystar" satellite development process
Near the eve of the launch, there was an epidemic in Wuhan, and the original plan of the school to go to the scene with the team to participate in the launch mission was cancelled, and Song Yufei, who had been staying at the launch base, became the only representative.
"Every time the star arrow is successfully separated, everyone will applaud enthusiastically and then wait for the next satellite to separate." On February 27, Song Yufei sat behind the computer in the 508 command and control hall of the Wenchang Satellite Launch Base and watched as "Daystar" was successfully separated in the sixth place. It was not until 14:11 that the ground station received the "Daystar" satellite measurement and control signal that "the stone in my heart finally landed." ”
Talking about the difference from laboratory research, Song Yufei admitted that the situation that needs to be considered has obviously changed: "In the past, tests were mostly carried out under ideal conditions, and now we must consider more about the practical application of the project. For example, under vibration conditions, how to ensure the reliability and stability of the equipment? ”
At the launch site, he found the answer: "If you can always maintain a rigorous attitude towards work like the space crew, I don't think there is anything that can't be done." ”
"Full of fulfillment and gain"
"One arrow and twenty-two stars successfully launched!"
The hot search on February 27 was flooded with major media. The first time it was on the hot search in this way, the members of the Wuhan University "Daystar" satellite team were both excited and excited.
"The project went all the way through the launch, and the team's efforts over the past few years have finally borne fruit. Now, it's full of fulfillment and gain! Lin Weihua of the R&D group is an undergraduate student in the School of Remote Sensing Information Engineering of Wuhan University, and because of the epidemic, the original plan to go to Wenchang, Hainan to see the rocket launch failed. Although it is not the first time to watch the live broadcast of the rocket launch, she still can't hide her joy when she sees the circle of friends and the network are all pictures of successful launches.
Lin Weihua has been involved in the preliminary selection and design of the satellite hyperspectral working band, which is relatively tedious and boring. There are huge data in the project that need to be carefully sorted out, and many different research methods of the scientific research predecessors need to be summarized and the optimal results obtained through team discussion, which requires Lin Weihua to have more care and patience.
But all this effort was worth it. Participating in the satellite development project not only provided her with the opportunity to translate the theoretical knowledge learned in the classroom into practice, but also, after the successful launch of "Daystar", the students of Wuhan University had their own platform to collect all kinds of data when they conducted scientific research in the future.
Rao Keyi of the School of Remote Sensing and Information Engineering of Wuhan University is also one of the team members, mainly responsible for carrying out the application research of satellite imagery in the later stage of "Daystar". The successful launch of this satellite is also a practical test of his years of learning achievements.
In Rao Keyi's view, a prominent feature of the research and development process of "Daystar" is that the degree of student participation is very high. Moreover, the satellite design process requires close cooperation between the various teams. After effectively participating in such a large project, Rao Keyi came into contact with students of different majors and teams in different research directions, and his knowledge reserves and professional vision were greatly expanded, which was of great help to improve the logic and scientific research ability of thinking about problems.
"The intersection of disciplines and the precipitation of knowledge have given the whole team a deeper learning understanding of satellite research and development, and also allowed everyone to touch more fields and learn knowledge outside of this major." Zhang Xuefeng, a doctoral student at the School of Remote Sensing and Information Engineering of Wuhan University, is responsible for the construction and commissioning module of the digital satellite system. In order to develop digital satellite systems, Zhang Xuefeng, who studied software, has to deal with many hardware: every part, he must understand, test, and practice.
"When I first started out, I often encountered difficulties. The teachers would come over every ten minutes to help us, and after a few days of debugging, we finally set up the digital system. I had never completed such a major task in such a short period of time before, and I felt like I had grown a lot! ”
Complex satellite design and manufacturing is far more complex than algorithms and software development, which also allows students to exercise full-chain system thinking. For Zhang Xuefeng, in the "Daystar" project, students with a single disciplinary background are fully familiar with and master satellite-related technologies and applications by participating in the development, launch, monitoring, etc., and then grow into compound talents in the field of remote sensing. This is undoubtedly a great encouragement to all the young students involved in the project.
Source: China Youth Magazine