Chang’e 4’s Historic Mission to the “Dark” Side of the Moon Inspires Bright Young Minds

.

The following article, fascinating in its content about this “first” in human history, presents a stimulating dialogue between a Professor from New York University, Pioneer Scholars (students who have completed the Pioneer Global Research Program), and students who follow Pioneer Academics on social media.


………………………………………………… …………………………….

.

.


.

………………..

…………………………………………………………………………………………………………….

The Chinese Lunar probe named Chang’e 4 successfully landed on the far side of the Moon at 2:30am GMT Jan 03, 2019. It is the very first time in history that humans have explored the Moon’s so-called “dark” side, which, until now, has remained something of a mystery. Though it is not really dark– the Sun shines there, too– the far side of the Moon has been called “dark” because it never faces Earth due to what astronomers call “tidal locking.” The Moon rotates on its own axis at exactly the same rate that it orbits around the Earth. It takes the Moon 27.3 days to rotate once on its own axis, and it also takes 27.3 days for the Moon to make one orbit around the Earth. The result of tidal locking is that the same side of the Moon faces the Earth at all times.  This situation creates a major challenge for space explorers: the far side of the Moon is shielded from radio transmissions from Earth, thus preventing any direct communication– this is largely what prevented previous exploration of the Moon’s far side. China’s Chang’e program developed a plan for indirect radio contact by relaying signals through a Chang’e satellite, called the “Magpie Bridge,” located far beyond the Moon’s orbit to allow the Chang’e lander to communicate with Mission Control back on Earth.

.

Chang’e is the Chinese Moon Goddess. In the legend dated circa 2400 BCE, she stole the immortality pill and rose up to the Moon trapped as a fairy goddess. Four thousand years later, China developed advanced technology to unveil the myths of her “Lunar palace” that had remained unexplored by mankind.

.

For the past eight years, Professor Farzad Mahootian has been a Clinical Associate Professor at New York University. His research has been published in the Boston Studies in Philosophy of Science, and Cambridge University Press, among others. Dr. Mahootian has been awarded grants from the Arizona State University Institute of Humanities Research, Templeton Foundation, National Science Foundation Grant, and NASA Learning Technologies Program Cooperative Agreement. He has developed and evaluated programs for NASA with the support of Raytheon Technical Services Company. Through his experiences, Professor Mahootian has conferred with scientists, teachers, and students and is proud to admit he has learned a lot from all parties; during the internet boom of the 1990s, he helped to provide students and teachers with an online curriculum that gave useful online access to a database of satellite data of the Earth and other planets, so they could acquire information previously used only within the scientific and scholarly community.

.

Pioneer interviewer:

.

What do you think of the technological breakthrough in Chang’e 4?

.

Laura from the US participated in Pioneer Academic’s astronomy field in spring 2018; her research paper is entitled “Blazar Jets Kinematics and Related Topics.”

.

I think that the greatest part of this mission is actually the autonomous program that China used to land the craft. In the early years of space flight, many astronauts were pilots who were used to flying planes. Now the planes fly the astronauts. The program had to analyze the mountainous terrain and choose the best course of action which resulted in a fantastic soft landing.

.

The relay satellite is also an ingenious way to fix the problem of communication from the dark side of the Moon. This showcases the brilliance of China’s satellite technology which is working on setting up a competing chain of satellites to the standard GPS.

.

Linda from China, submitted her questions through the Pioneer community:

.

Successful and ambitious! One of the main challenges to land on the “dark side”(it’s not actually dark though) is communication. The relay satellite “Queqiao” covers the distance of about 400,000 kilometers and can still precisely pinpoint the signals from earthbound scientists and signal back, which is referred as the so-far furthest satellite laser ranging.

.

Mahpara from Bangladesh engaged in a mathematics experience with Pioneer Academics during spring 2018 while taking a gap year. Her research paper is entitled, “Zeckendorf’s Theorem for Narayana’s Sequence.”

.

An unprecedented feat! The autonomous landing, especially in such bumpy terrain, is definitely a marvel. I was also fascinated by how they overcame the communication restrictions the mission imposed.

.

Tommy from Canada studied physics through Pioneer Academics in the summer 2018 semester; his research paper is entitled, “Sulfur K-edge micro-X-ray Absorption Near-Edge Spectroscopy (XANES) using synchrotron radiation.”

.

The recent success of China’s Chang’e 4’s Lunar landing mission opened up a brand-new chapter of space exploration not only for China but for the entire world. This is the first time in human history that a spacecraft landed on the far side of the Moon where most signals to communicate to the Earth are cut off. The technological breakthroughs in this mission are simply astounding. Due to the blockage of signals, the Chinese National Space Agency was not able to directly communicate with the spacecraft and the rover Jade Rabbit. Instead, the signals were relayed through the satellite Queqiao (Magpie Bridge) which is in a “halo orbit” on the far side of the Moon. Furthermore, during the final phase of the landing sequence, the whole process is completely autonomous, since China did not have manual control over the spacecraft whatsoever. The spacecraft was able to scan the surface, identify obstacles, measure the slopes of the terrain, and select an ideal spot for touch-down. In the end, Chang’e 4 performed a slow vertical descent and landed softly in the Von Kármán crater within the South Pole-Aitken Basin. The above landing procedure was not only impressive but also critical to the development of future Chinese and international space missions. The success of this mission provides important information for future autonomous landings of a spacecraft.

.

Chang’e 4 also carries a suite of highly sophisticated instruments including scientific payloads developed by the Netherlands, Sweden, and Germany. The low-frequency radio spectrometer will be installed on the Chang’e 4 relay satellite. Another low-frequency radio instrument will take advantage of the shielding of electromagnetic interference from Earth on the back side of the Moon and will create a new low-frequency map of the radio sky. This mission not only demonstrated the technological advancements that China has made in the past few decades, but more importantly, it demonstrated the importance of international cooperation and the sharing of knowledge between space agencies. With researchers, engineers, and physicists from around the world, Chang’e 4 ventures into the uncharted territory of the Moon opens up infinite possibilities of discovery.

.

Professor Mahootian:

.

Chang’e 4 is a brilliant, simple solution to exploring everything that is out of Earth’s view of the Moon. I thought the concept of a relay with the Magpie Bridge was a wonderful and unique idea because, as far I know, no one has tried this before; no one has utilized a space communication relay in this way and for this purpose before.

.

There have been four previous Lunar mapping missions over the last 50 years that have made some beautiful maps of both the near and far side of the Moon, but actually being there is a  whole other level of engagement. To land on the far side of the Moon and collect samples is something no one has ever attempted before. It represents true originality of thought to locate Chang’e “Queqiao,” the Magpie Bridge communication satellite at a point 1.5 million kilometers from Earth, at a stationary point relative to the Earth-Moon axis. To understand where in space Queqiao is located relative to the Moon, this space.com article and diagram are helpful, but this animation is even better. The main concept to understand about Queqiao is that it has continuous direct line-of-sight contact with both Earth and the Moon’s far side.  This relay satellite is not motionless at L2, but rather moves in what has been called a “halo orbit” around this point.

.

Pioneer interviewer:

.

What do you admire about this mission?

.

Laura from the US:

.

I admire the guts that this took. An Apollo 17 astronaut had recommended that NASA undertake a similar venture with a relay satellite, but the cost and risk involved discouraged NASA from attempting it. The idea of a relay satellite was discussed, but China deserves credit for the decision to implement the idea.

.

Linda from China:

.

This mission is an unprecedented expedition broadening the knowledge of human beings about deep space. Since the far side of the Moon retains pristine craters left by violent collisions during the early history of the solar system, Chang’e 4 might reveal the formation and development of the system we’ve been living in.

.

Mahpara from Bangladesh:

.

The tenacity and perseverance that everyone worked with in order to attain success is definitely admirable, considering the technical struggles they had to go through. For me, it stretches even beyond that for the amazing leap of faith that the scientists took in this mission. Even at the very final moments before the landing, when the probe was absolutely in a remote communication zone detached from the launch committee, they were confident. This is definitely the most admirable feat of the mission in my opinion.

.

Professor Mahootian:

.

Between the sun, the Moon, and the Earth, there are a number of Lagrange points, relatively stable areas in space where there is balance between the gravity of the Sun, Earth, and Moon. These have been used in the past for space telescope placement. Most Lagrange point satellites are orbiting Sun-Earth Lagrange points to observe the Sun and warn us of solar activity that might cause space weather harmful to Earth. Currently, Queqiao and five other missions are placed at the L2 Earth-Moon Lagrange point. From this position, Queqiao receives signals from the Jade Rabbit rover on the far side of the Moon and relays them back to Earth. And what’s so clever and brilliant about it is that it has one simple job: it’s exactly the right thing in the right place for the right job.

.

There’s a lot to appreciate about this mission but what stood out the most to me is the biological experiment. I found Chang’e experimental mini-biosphere quite unexpected. I thought the lander and rover would just collect data, but they are actually running an experiment to see how life can respond to extended exposure to the Moon’s gravity, which is about a sixth of Earth’s. No biological experiments have been done anywhere that far from the Earth: there have been biological experiments on the International Space Station, but the space station is on a low-Earth orbit and the acceleration of gravity is almost the same as on Earth. So, the Chang’e mini-biosphere is the first real biological experiment taking place so far from the Earth, where the force of gravity is significantly different. To my understanding, this is a first step in studying life far from the Earth. Such knowledge will eventually be useful when setting up a colony on the Moon, and perhaps even one on Mars. So this is a very exciting first step for life beyond Earth.

.

Pioneer interviewer:

.

What discoveries do you look forward to making through Chang’e 4?

.

Laura from the US:

.

Chang’e 4 measures many things, but three stand out to me. The rover will test if silkworms and other biological matter can grow in zero gravity, will see what radiation exists on the Moon, and will study the cosmos without interference from Earth. The biological and radiation measurements are presumably to see if life on the Moon is possible, and I sincerely hope that the mission helps to pave the way for a Moon station.

.

Linda from China:

.

It sustains ample energy resources so that when we explore deeper into space in the future, it can serve as a refueling station. Also, I’m really looking forward to the more accurate and “noise-free” cosmic background radiation obtained from the far side of the Moon (we use microwaves or radio waves to probe everything in the universe!) We have already had the best baby picture of the universe taken by the WMAP; it will be terrific to have some good pictures of the teenage universe and hence the evolution of it.

.

Mahpara from Bangladesh:

.

I look forward to an astrochemical accomplishment. As the Moon’s other side has never been explored before, perhaps the probe will be able to collect samples of craters and rocks to compare them against other samples, which I think will provide some insights into the Moon’s formation and the future utilizations of the environment of the satellite.

.

Tommy from Canada:

.

I am incredibly excited to see the material composition of the Lunar crust and mantle since it might contain rare or even unknown substances and minerals. The equipment on Chang’e 4 can also help construct a detailed analysis of the rock composition of the Moon. Furthermore, with the low-radiofrequency equipment on board, Chang’e 4 can also potentially uncover some hidden secrets of the history of our Moon. Lastly, Chang’e 4 also carried a mini biosphere experiment chosen from around 200 student submissions. It will test photosynthesis and respiration in the low-gravity Lunar environment of Arabidopsis seeds and silkworm eggs.

.

Professor Mahootian:

.

Chang’e 4’s biosphere is a unit containing silkworm eggs, seeds of different plants, and yeast. This very simple, minimal ecosystem is completely sealed and is entirely self sustaining: once the seeds germinate and start to respire, the system would develop a balance of a variety of gases, including oxygen, hydrogen, nitrogen, carbon dioxide and water vapor. Once the silkworm eggs hatch, the worms would take in the oxygen from plants and release carbon dioxide for the plants to absorb and in turn produce more oxygen for the silkworm. The closed ecosystem of plants and silkworms is based on an ecological concept: the whole idea is to see how long this system could be self-sustaining under conditions of low gravity. We don’t know how long this system will last but as long as it is kept warm enough, we’ll find out how long it can be self-sustaining: maybe silkworms and plants will produce offspring.

.

It is interesting to note that of all the animals possible for this mini-biosphere mission, scientists chose the silkworm which is incredibly important to Chinese history, culture and civilization. Silk is a Chinese invention and one of its major historical contributions to global civilization. I believe that the scientists of the Chinese space program are honoring their wise and resourceful ancestors in choosing the silkworm out of all the other types of worms or insects for this historic ground-breaking experiment.

.

Pioneer interviewer:

.

What is your biggest unsolved question about the Moon?

.

Mahpara from Bangladesh:

.

Different aspects of the Moon have always baffled me. But I guess the most perplexing would have to be the Moon’s formation. The multiple theories proposed with a view to explaining the event are not without their challenges as well. When I first read about the impact hypothesis which included the idea of an object crashing into Earth, I also read about the limitations it posed: the debris found by Apollo presented a difference in the composite material of the Moon and the suggested source that it originated from. Although many other ideas have been proposed after that, none are without their limitations.

.

Professor Mahootian:

.

I think it’s still a question of how the Moon was formed or captured. From time to time, the scientific community has more evidence to show it was captured. And at other times, more evidence suggests the Moon was formed via collision. It goes back and forth. The origin of the Moon is probably one of the biggest questions.

.

I don’t have a theory that’s actually based on new evidence, but I like the idea that the Moon was formed due to capture and collision.

.

Pioneer interviewer:

.

What is the most exciting astronomical event for you?

.

Laura from the US:

.

Personally, I love blazars and far away galaxies, but that is not applicable to this case. Blazars are the furthest, brightest, and oldest objects in the observable universe. My interests are centered far away, but the Chang’e 4 landing shows how much we need to learn about our own backyard before we venture to the ends of the universe.

.

Linda from China:

.

SpaceX launched a Tesla Roadster into orbit around the sun by its Falcon Heavy in February 2018. Both this and Chang’e 4 are exciting for taking a crucial step toward long-term human missions beyond Earth.

.

Mahpara from Bangladesh:

.

The most exciting astronomical event from my perspective would definitely be the detection of gravitational waves. (Pioneer offers this research topic in physics). The idea of hearing back in time through the ripples in the space-time fabric is amazing to me. Most recently, another detection also provided an insight into the interstellar origin of noble metals in the Earth through a neutron star merger. This was an unprecedented feat in the field of gravitational field astronomy. I am certainly looking forward to the results that the LIGO Virgo collaborations bring forth in the future.

.

Professor Mahootian:

.

As far as astronomical events go, I think one of the most interesting was the Shoemaker Levy-9 Comet collision with Jupiter. During its final orbit of Jupiter, the Shoemaker-Levy Comet broke up into 23 pieces and looked like a chain or “necklace” of cometary fragments which eventually hit Jupiter at an angle that was partly visible from Earth,  so we have photographic and video records of the collision (see: https://www.youtube.com/watch?v=CiLNxZbpP20 ). We discovered comets can break up in endless formation. The comet broke up due to Jupiter’s gravity because comets are mostly composed of ice and rock. 

.

~~~

.

Stayed tuned for a second article next week in which Professor Mahootian answers student questions!