fudan teachers and students build satellite payloads to study and predict the mechanism of solar explosions and go to space to listen to the "breathing" of the sun
2024-10-07
한어Русский языкEnglishFrançaisIndonesianSanskrit日本語DeutschPortuguêsΕλληνικάespañolItalianoSuomalainenLatina
on september 24, the jielong 3 carrier rocket was launched. photo courtesy of china long march rocket co., ltd.
on september 24, the jielong-3 carrier rocket flew into space carrying the "fudan-1 (lancang-mekong future star)". reporters from china youth daily and china youth daily learned that this is the first satellite jointly developed by fudan university and shanghai aerospace technology co., ltd. relying on the relatively complete domestic industrial chain and streamlined design, its hardware cost is only that of foreign countries. a "fragment" of satellites with similar scientific targets.
although there is not much "krypton gold", it shoulders the important task of exploring a profound knowledge - studying the mechanism of predicting solar explosions, and analyzing why and when the sun's surface "explodes". yang yang, chief designer of the main payload of "fudan-1 (lancang-mekong future star)" and associate professor of the department of nuclear science and technology at fudan university, told reporters that the "explosion" on the sun's surface is actually a concentrated burst of plasma on the sun's surface.
"just like what is described in the science fiction movie "the wandering earth 2", once there is a 'big explosion' on the surface of the sun, the high-energy particle storm it releases may destroy space facilities." yang yang introduced that he and 6 people the "fudan-1 (lancang-mekong future star)" ultraviolet load developed by fudan students jointly analyzes the cause and scale of this "explosion" by continuously collecting data on the plasma movement on the sun's surface. "with this satellite, we can get first-hand information on solar plasma parameters and build our own prediction model."
"building a dojo in a snail shell"
the sun is a constantly active "living, breathing" plasma ball, and its normal surface activity generates solar wind. high-intensity solar wind has a greater impact on humans, mainly originating from the outward jet of plasma during the corona (outermost atmosphere) mass ejection process. this plasma is accelerated to the point where the sun's gravity cannot "pull" it, and then travels along the sun's magnetic field lines to reach the vicinity of the earth. because it has extremely high kinetic energy and carries a large amount of charge, it will have a huge impact or even damage man-made electronic equipment in the near-earth airspace.
yang yang told reporters that in order to clearly study the movement of plasma on the solar surface, "fudan-1 (lancang-mekong future star)" needs to collect enough data. however, it is extremely difficult for this satellite to "stand firm" in the harsh environment of large temperature differences and full-band irradiation, and to withstand medium and high-energy particles from the sun and the earth itself.
not only that, this satellite must also have enough "spectral photography technology" and "data refresh speed" to "photograph" the constantly active flare plasma in specific areas. and this ability is not easy to achieve.
the so-called spectrum photography is to accurately identify the color of each pixel in the photo. the "strongest" trained human eye can distinguish different monochromatic lights with a wavelength difference of 1 nanometer, but spectral photography requires the resolution of monochromatic light below 0.05 nanometers. this is equivalent to using spectral technology to insert more than 20 gradient colors between two adjacent lipstick colors that the most sensitive women can distinguish.
yang yang introduced that the current spectral shooting accuracy of "fudan-1 (lancang-mekong future star)" can reach 0.03 nanometers, which is the "best" among satellites with similar functions developed by our country.
"in the past, satellites used the prism route, but we chose the higher-precision grating technology route." yang yang said, "fudan-1 (lancang-mekong future star)" not only has high resolution, but also has a fast screen refresh speed, creating a 280 nanometer the refresh speed in the ultraviolet band is the "best". it can refresh the details of photographing plasma bursts on the sun's surface in as fast as 0.1 seconds. the previous fastest speed of similar satellites in the world was 1 second.
in fact, if you want to obtain ultra-high spectral resolution, you can just make the satellite larger. but the difficulty for the development team is to control the side length of this small satellite to 50 centimeters according to various restrictions.
"in small satellites, we try to make the light run diagonally so that its focal length can be longer. the longer the distance, the higher the resolution." yang yang said that large satellites can achieve 10-20 meters. in contrast, "fudan no. 1 (lancang-mekong future star)" is a dojo in a snail shell, "we have specifically designed the entire optical path."
“spend a little money to do big things”
the "fudan-1 (lancang-mekong future star)" development team also implements the line of "more speed, better economy". the cost of foreign satellites of the same type is measured in billions of dollars, but this small satellite only costs 1% of the former.
yang yang introduced that the secret recipe for "fudan no. 1 (lancang-mekong future star)" to save money is to "rely on the industrial chain and develop the core by itself." for example, the main payload "nu ke no. 1" spectrometer was "made" bit by bit by yang yang and his team using low-cost components relying on my country's relatively complete industrial chain.
"there are many small mirrors in the spectrometer. on the one hand, we need to study how to calibrate these mirrors with high precision so that they are light in weight and have accurate angles. on the other hand, we also need to study how to fix these mirrors and make them durable." yang yang introduced, " the spectrometer carried by fudan-1 (lanmei future star) must be able to withstand temperature differences between -50°c and 100°c. after thermal expansion and contraction, various optical devices will inevitably undergo slight deformation, directly causing "optical path "crooked", the "photos" taken become blurred, and the data collected are biased.
"just like your glasses, we usually use them without any problems, but if the temperature difference is too large, you will find some changes in thickness and structural deformation, which will affect the clarity of vision, and even serious causing the lens to break," yang yang said.
in order to allow the spectrometer to adapt to the huge temperature differences in space, they used a special "compensation structure." after thermal expansion and contraction, the strains of different structural parts cancel each other out and remain in place.
the fixing glue of the spectrometer is also a university subject. the team has tried a variety of imported and domestic glues to test their stability in extreme environments. in the end, the team found that a domestically produced glue performed well, and the cost dropped accordingly.
"our small satellite weighs about 50 kilograms, and the main payload spectrometer cannot exceed 2.5 kilograms. it must be light and resistant to radiation." team member tian ziqiang, a doctoral candidate in the department of nuclear science and technology at fudan university, told reporters that radiation resistance is simply understood as "sun protection". unlike humans on earth who protect themselves from sun and ultraviolet rays, "fudan-1 (lancang-mekong future star)" has to directly face the sun itself and other cosmic light sources.
plasma is a type of charged ion that "collides" into the interior of small satellites at high energy in space. if a satellite that is finally launched into the sky does not do a good job of "sun protection", it is very likely that it will be "blown" by space particles before it can collect data.
"we also have 4-5 layers of protective layers inside our small satellite. different layers have different characteristics and can all play a protective role." tian ziqiang said that the department of nuclear science and technology of fudan university has a super electron beam unique in taiwan. the ion trap device is a large scientific device used by generations of nuclear physics teachers and students. through this existing large device, team members can directly simulate the extreme environment of the corona to test whether the "stacked armor" of small satellites is effective. .
all kinds of fine modifications, extra work and weight loss were all worked out bit by bit by a team of teachers and students from fudan university. the main theme is to be "diligent and thrifty, and do it yourself without asking for help."
"looking for tiny fingerprints in huge photos"
it is worth noting that the launch of this small satellite will become a model for scientific and technological cooperation among the six countries along the lancang-mekong river.
in 2019, in order to implement the consensus reached at the fourth lancang-mekong cooperation foreign ministers’ meeting on strengthening cooperation in education and youth, eight universities from the six lancang-mekong countries initiated the establishment of the lancang-mekong youth exchange and cooperation center, which is located at fudan university. other partner schools include the royal university of phnom penh in cambodia, qinghai university, guangxi university of finance and economics, the national university of laos, yangon university in myanmar, prince of songkla university in thailand, and the university of humanities and social sciences of the national university of hanoi in vietnam.
over the years, young people from the six countries have had close exchanges in the humanities field. this time, "fudan-1 (lancang-mekong future star)" will "fly" into space with the cooperation of young teachers and students from the six countries in the field of science and technology.
"the satellite payload was developed by the fudan team, but the precious solar data and its research and analysis obtained in the future can be shared with young teachers and students in the six lancang-mekong countries." said zhao qiang, secretary of the party committee of the institute of modern physics at fudan university.
yang yang told reporters that the "fudan-1 (lancang-mekong future star)" collecting data on plasma motion on the solar surface is only the first step in studying solar explosions, and will be followed by the arduous work of "spectrum interpretation".
the data hasn't come yet, but huang shihan, a master's student in the department of nuclear science and technology at fudan university, is already making preparations to "unravel the spectrum." he collected previously published research data on solar plasma from various countries around the world, preliminary compiled algorithms and prediction models, and waited for the latest data from "fudan-1 (lancang-mekong future star)" to be in place.
"'spectrum interpretation' is like looking for tiny fingerprints in a huge photo." huang shihan told reporters that after the actual spectrum data of the solar surface plasma comes back, he and his team members will extract effective data from the spectrum. based on these data , designing and running ground experiments on the only super electron beam ion trap device in china, repeating and simulating the process of the solar surface, and in the process of analyzing the differences between experiments in the sky and on the ground, clarifying the advantages and disadvantages of the theoretical model and iteratively improving it, so as to find the movement rules of plasma on the sunrise surface.
in this process, young people and senior scholars from the six lancang-mekong countries can participate together. "not only will we share data, we will also visit each other on a larger scale, send students to each other, jointly build data receiving stations, and jointly build international cooperative research centers." yang yang said.
the latest news is that at the lancang-mekong regional governance youth innovation design competition held not long ago in phuket, thailand, fudan university demonstrated satellite development and application to young people from six countries and launched the recruitment of a transnational scientific research team. next, we are waiting for the valuable data sent back by the chinese satellite.
china youth daily·china youth daily reporter wang yejie source: china youth daily
(source: china youth daily)
