The so called “Scorch” brutally hot summer has gone. I hope all folks have been staying well. Well, this month, the Miyazaki Lab, Department of Aerospace Engineering, College of Science and Technology, Nihon University, launched their own satellite, Hurrah!!! So, I took a trip to interview those who worked on the project in the Funabashi City lab in Chiba prefecture!!

Miyazaki Lab, Department of Aerospace Engineering, College of Science and Technology, Nihon University

A while ago, there was a post Twitter that said “The International Space Station (ISS) will soon be passing over Tokyo. It can be seen in the northwest sky”. While walking outdoors, I was wondering “Will it be possible to see it? I hope so.” Then a flash of light as bright as a star, much faster than an airplane was passing by in front of my eyes!! It was my first experience seeing ISS! It was so impressive!!

This time, my news gathering trip for Exploring Ham Radio World was to visit and interview those who made their own satellites. Apparently, the satellites are also equipped with an amateur radio beacon and transponder. Remembering my first experience of seeing ISS, this subject intrigued me even more.

The place I visited was the Funabashi Campus of Nihon University, located in Funabashi-City in Chiba prefecture. I got off the Toyo High Speed Rail at Funabashi Nichidaimae station, and saw the campus immediately after exiting the station ticket wicket.

Visiting the Nichidai Funabashi campus

In the campus is a wide, straight road like an airport runway! It has used for human powered glider. In 2019 television program titled Bird Man Contest, there was a student new record of 38010.28m established. The aircraft that established record in man powered flight by Association of Aeronautics, College of Science and Technology, Nihon University was also produced at this campus.

In the campus is a wide, straight road like an airport runway! It has used for human powered glider. In 2019 television program titled Bird Man Contest, there was a student new record of 38010.28m established. The aircraft that established record in man powered flight by Association of Aeronautics, College of Science and Technology, Nihon University was also produced at this campus.

About NEXUS

NEXUS (NExt generation X Unique Satellite) is the 4th micromini satellite produced by the Department of Aerospace Engineering. It is a 10cm long, 10cm wide, 10cm high “1U CubeSat”, that weighs approximately 1.3 kg. The main subject of the research is “Demonstration for New generation amateur satellite radio technology”. Many amateur radio transmitting devices are included in such a compact device.

The 1U NEXUS CubeSat was co-development by Nichidai and JAMSAT. It has 5 radios and 4 antennas (Photo (C) JAXA)

The main transmitting devices of NEXUS
・Linear transponder (0.5W) of 145MHz → 435MHz
・Beacon transmitter (437MHz 0.1W) notifying the status of satellite by CW
・FM transmitter (437MHz 1200bps 0.8W)
・QPSK transmitter (435MHz QPSK 38400bps 0.3W)
・FSK transmitter (435MHz 1200～19200bps 0.4W)

Callsigns
・Satellite Control Station: JS1YAW (JARL station, established in 2018)
・Satellite Station: JS1YAV (JARL station)

Today there are many worldwide research institutions, universities, and other groups, that have developed micro-mini satellites, launched by rockets, or released from ISS. NEXUS features both QPSK, which exceeded the speed of conventional micromini satellites, and a speed changeable FSK transmitter!

Moreover, there is a unique mini camera on board that they developed. It has full-HD resolution, and can transmit photographs back to earth at a high speed.

Mr. Nakamura added: “Not only Nihon University, there are more groups, like universities and corporations that have developed micromini artificial satellites and launched them recently. Each of the satellites seem to be given more sophisticated and diversified missions, and so the communication data tends to increase in volume. Information provided by JAMSAT, a specified non-profit organization in Japan, that “high tech, such as π/4 shift QPSK transmitters with high speed but low power requirement, an FSK transmitter with changeable transmitting speed, and Linear Transporter with analog data link-up and electrolytic level measuring are now under development”. JAMSAT then proposed “We shall conduct an demonstration in orbit, by combining those higher technology transmitters onto the micromini artificial satellite that was developed by Nihon University”. The agreement was immediately responded to positively by the university. As result, a project of Nichidai and JAMSAT joint development of NEXUS was born.

The moment of locating the completed NEXUS onto the CubeSat ejector (photo(C)JAXA)

As this co-development continued, on January 18, 2019, the Uchinoura Space Center in Kagoshima successfully launched Epsilon rocket #4 of JAXA, carrying the RAPid Innovative payload demonstration Satellite 1 (RAPIS-1) and 5 other micromini satellites. They are currently in a 90 minute orbit, at an altitude of about 500 km above the earth. All satellites separated normally.

At 9:50:20 on January 18, 2019, the Uchinoura Space Center launched Epsilon rocket #4. (photo(C) JAXA)

By the way, of the 14 members at Miyazaki Lab College of Science and Technology where I was about to visit,1 is studying for doctorate, 7 for master’s degrees and 6 students are in their 4th year for a bachelor’s degree. In the group, 6 have 3rd class Amateur Radio Operator licenses.

Tour of the radio shack and controlling antenna

Following Mr. Nakamura’s lead, we arrived the radio shack on the 4th floor of building No. 3. The radio shack, a classroom that was as used as a laboratory for the students, now also plays a role as the earth station for controlling NEXUS.

On the 4th Floor of the building No. 3.

Mr. Takeru Nakamura (left) and Mr. Ryota Nakamura (center) are in the 2nd year of their master’s degree studies, explain the equipment in the radio shack.

“I wonder what the radio shack looks like” I thought while walked into the room with excitement. What I saw was a huge 4-screened computer, 4 Amateur Radios (2 IC-910 and 2 IC-9100) to be used to receive signal from satellites and send out data, as well as a modem used to analyze signals from the satellite. Also, there are antenna controllers to adjust the direction (up-and-down elevation, right-and-left azimuth angle) to aim the antennas in the direction of the satellite. I also found a set of IC-9700 radios at the JS1YAQ JAMSAT Club Station there. It brought a sense of familiarity to mind seeing ICOM radios actively involved, too.

When NEXUS flies over, the temperature, battery voltage, current, and position of the satellite, data (telemetry signal) that are transmitted from the satellite to the ham shack by Morse code to be analyzed. The earth station can send commands to turn the transmitter ON or OFF, if necessary, and other commands, as the satellite is constantly observed to check its condition.

Control desk with a large 4-LCD monitor that displays a variety of data at the same time

Amateur radios are used as controlling devices. In the middle rack, there are 2 IC-910s and 2 IC-9100s. The elevation and azimuth angle of 2 antenna stacks can be adjusted to aim at the satellite. Also, an IC-9700 for the JS1YAQ JAMSAT Club Station is on the bottom rack.

I asked Mr. Nakamura “Is it hard to catch all signals from NEXUS that flies over every 90 minutes? Can you sleep or go out for fun on Sundays?” He replied with amusement, “Above the sky of Japan” means that the satellite follows the orbit and transmits signals to this very radio shack several times a day, so it is not an issue to be concerned with. On top of that, all members in the lab are taking 2 person shifts for surveillance. However, we did have a bit of a problem since entering the facility was strictly controlled during the peak of the COVID-19 pandemic.” Even places like this had been negatively affected by the pandemic.

As I was led to the roof top of building No.3 to continue the tour, I found couple of antennas were there to track the satellite!!

Antennas for tracking satellites on the roof top. Left: A 144/430MHz circular polarized antenna stack used for other satellites that were launched before. Right: A 144/430MHz antenna stack used to track NEXUS 144/430MHz, both vertically and horizontally polarized.

Currently the antennas are 2 x 12 Element Cross Yagi for 144MHz, and 2 x 2 x 20 Element Cross Yagi for 430MHz. Controlled with 2 rotators for elevation and azimuth, they constantly track the satellite from the point it appears on horizon, then across sky until it disappears over the opposite horizon.

How interesting, I thought. The Cross Yagi antenna doesn’t just utilize circularly polarized waves in order to improve the accuracy of transmitting and increase decode ratio for the packet, it utilizes the combined linear polarization diversity from vertical and horizontal polarization signals that are sent to separated radios (which is the reason of 2 sets of IC-9100 are used). Each of the antennas are also equipped with low noise preamplifiers.

The actual movement of the antennas were shown to me as well. While rotating left and right, and up and down, their rapid movement reminded me of the robot arms at automotive factories I have seen on TV.

Miss Fujii, a first year of master’s degree student who oversees the ground station’s equipment for NEXUS, taught me a lot about antennas.

Tour to the Department of Aerospace Engineering conducts

While waiting for the NEXUS flies over, after we finished our tour on the roof top, I was suggested that we have a look at what research the Department of Aerospace Engineering is doing.

The first stop was to the Techno Place 15 building. Here, not only the Department of Aerospace Engineering of Science and Technology, but also Civil Engineering, Oceanic Architecture and Engineering and Mechanical Engineering and other departments have set up experimental facilities. It was a nice surprise to see wing components for Cessna and other aircraft displayed in the room.

There was a huge vacuum chamber set up in the room. Before NEXUS, other satellites were developed, and this machine was used to vacuum the internal of satellites in order for them to function accurately in outer space, as well as to test if the antennas are designed correctly and function as planned.

This vacuum chamber was set up in Techno Place 15. Utilizing a vacuum pump to suck out the internal air in order to conduct a test.

In addition, Mr. Asuka Tatara, a 2-year master’s degree student in the Miyazaki Lab explained that the research they are conducting is to develop a gigantic thin film (solar sail) and how to expand it.

The measurement of this sail is about 14m diagonally, a huge unit (what they showed me was only a 1/14 model of it). The item is stored inside the rocket during the launching and must open as a sail on the satellite enters its orbit. It is a very difficult technology. The main purpose of the sail is to absorb particles from the sun when sunlight shines on it. The particles then turn to “power”, for not only acting as a source to move the satellite, but also to provide a large amount of power for the attached solar batteries for charging.

Mr. Tatara explained the research of developing a gigantic film solar sail for the satellite and expanding it to open. The actual sail in the photo is only 1/14 of the actual size sail.

The tour continued to the basement of building No.3, where the lab for developing and experimenting of NEXUS is located. To prevent dust, the entrance area was covered up by plastic sheets like a cleanroom.

In the basement of building No. 3 is the development and experiment lab for NEXUS

As soon as I entered, I saw a square “box” on the table. Is that NEXUS, I asked.” Yes, this is the prototype of NEXUS.” he replied.

Mr. Takeru Nakamura showing the NEXUS prototype to me.

Wow! I was taught it was a 10cm cubic micromini satellite, but it seemed to be even smaller in reality! Electric parts are lined up, installed tightly on the 3-D overlapped base plates without any space wasted.

A 10cm cubic micromini satellite base plate tightly installed with electric parts! Front right is QPSK transmitter, the far back PCB board with the antenna is the JAMSAT FSK transmitter. In the front center, is the PCB board of the JAMSAT linear transponder. “Did you make the PC boards?” I asked. He replied, “there are some made by us, and some provided by JAMSAT. Also, those modules are ordered from professionals … all kinds stuff.”

The components are way too tiny. Soldering for assembly is not possible, I thought. It is hard to imagine and understand parts like this to be sent 500km above earth into space, and constantly orbiting while sending radio signals.

There was an experimental station right next to us, with a section for research on how to separate the satellite from the rocket in the outer space. Separation has to be done with simple methods, such as developing new structured items, instead of counting on motors or other power sourced devices.

Mr. Sato and Mr. Ryota Nakamura placed a gear attached component on an acrylic plate. “Now, we are going to perform an experiment on expanding the structured item. It happens in a very short moment so please watch closely.” As soon as the two of them let go of the structured component, the satellite split into 3 parts and a thin metal plate extended and expanded into a triangle.

Mr. Sato and Mr. Ryota Nakamura were showing me an expanding experiment of a structured component. As they let their hands off, the thin metal plate extended and turned to a triangle!

It was so fast! Once the film in between this extended metal plate expands to utilize the power source from sunlight, it can provide power to solar batteries, use the power to help expanding antennas and a variety of experiments are conducted.

Somehow, I felt that I have seen this metal plate elsewhere. “It is actually a regular metal tape measure. We made this by combining two tape measures,” he said with a light laughter. We were inspired by the feature that tape measures being able to extend and wind. The gear and other parts are made by a 3D printer. “Due to a higher possibility of failure when utilizing motors, our strategy is to avoid power motivation and find alternative methods with higher possibility to work.”

A metal plate is regular tape measures. Gears and other components are made using a 3D printer

Inspiration from everyday items is such a fun experience. There are many items based on the idea of “you never know what will work if you don’t try”, so the room is full of immediately available tools such as a 3D printer, components and parts that can tolerate the wide temperature changes (-60～+150℃) in outer space.

Tools must be prepared for experiments, 3D printer (left) and environmental testing equipment (right)

NEXUS passing through the sky above!

It is about time for NEXUS to pass above Japan, we returned to the radio shack.

Mr. Sato and Mr. Ryota Nakamura are sitting at the desk and setting up various software to be ready to receive signals from the satellite. As we waited tensed and nervous, the IC-9100 received a Morse signal (telemetry signal) from the satellite. The signals grew stronger over time.

NEXUS is just about passing in the sky above. These two staff members are nervously ready to send uplink commands.

Commands will be sent to NEXUS at this orbit to turn the transponder ON. If it is successful, Masaco can try to make a QSO through the NEXUS in the next orbit. “Wow, that will be great! I hope the commands went through successfully”, I said. The two entered commands to turn the transporter ON, then after checking for errors sent them on 145MHz. Moments later, from the 437MHz transmitter, a Morse signal “UPLINK IS OK” retuned. It worked!

The uplink command to turn transporter ON completed successfully! A Morse signal of “UPLINK IS OK” was received.

The staff members went on analyzing telemetry signals that just arrived to check the status of the satellite. Then, they proceed to write a report about the result, or tweet “Turned transporter for NEXUS to On” in English on Twitter. and do related tasks.

A quick interview with all staff members

There was about 90 minutes until the next NEXUS orbit, so I had the opportunity to gather all 5 of the NEXUS project staff members together and do quick individual interviews.

From left –Mr. Takeru Nakamura, Mr. Ryota Nakamura, Mr. Riku Sato

● Mr. Riku Sato (A 2nd year master’s degree student in charge of Structure, Mission Communication System, and Cameras)
Born in Tochigi prefecture. When in his sophomore year, he studied in one of the “Future Doctor’s Workshops”, a satellite workshop of by the faculty of Science and Engineering. It was then that he became interested in structured units in outer space, which was a turning point for him to get involved with the NEXUS project.

Successfully launching into space a project that I took part in producing, and it is still active up there, gives me a sense of pleasure. The most difficult experience I had was when we were preforming a vibration test, to test if satellite could bear the impact during launching. I failed in storing the satellite into POD, which is a case to store the satellite when they launch the rocket. I was so worried that my failure would interfere with the rocket launching. In the end, the test had to be rescheduled on other day. I am working on becoming an aeronautics and astronautics engineer in the future.

● Mr. Ryota Nakamura (A 2nd year master’s degree student in charge of Command Receiving, and Mission Communication)
Born in Chiba prefecture. He is currently living with his family. He has been interested in aircraft for long time, so he aimed to be a student in the Department of Aerospace Engineering, Science of Engineering. Previously, when he was involved in developing and researching robots for aircraft, he started appreciating the fun of operating satellites, and decided to relocate and be with the NEXUS team.

With the NEXUS project, he used to take the responsibility for software. In the beginning, he had difficulty achieving confidence in the missions that he was given. Fortunately, after receiving instructions from many of his seniors, and Mr. Ueda and Mr. Kaneko of JAMSAT, plus being inspired with the correct way of thinking about research, he found the way to solve those obstacles. He would like to utilize the knowledge and experience that he gained from the NEXUS project to become an IT communication engineer in the future.

● Mr. Takeru Nakamura (A 2nd year master’s degree student in charge of Data Processing, Sensor, and Mission Communication)
Born in Kumamoto. He has been interested in aeronautics and astronautics since childhood. With the NEXUS project, he is responsible for command and data processing. While NEXUS was in developing, he borrowed equipment from another university to perform a thermal vacuum test. The day before the testing was scheduled, the satellite had to be completed to a certain level in order to perform the testing on. The experience of racing with time was a difficult task. It was worth it once NEXUS was launched and the first packet signal to be heard was his very own product. He wants to be a technology engineer, create products, and be a reliable adviser.

Left is Miss Yuka Hirose, Right is Miss Hitomi Fujii

● Miss Hitomi Fujii (A first year master’s degree student in charge of CW Generation System, Above Ground Station, and DQPSK Demodulation)
Born in Gifu prefecture. Miss Fujii is interested in mechanical engineering, but also wanted to be part of astronautics, so she eagerly joined this department. “I am one of the 20 female students out of 120 in total. I am glad to study about satellite development in the Satellite Workshop. The program was a first-time experience for me since I enrolled in the university. NEXUS is a ground station. I took the responsibility for development and improvement of the software of the uplink commands and downlink telemetry. The voice that is running in NEXUS is mine,” she said with laughter.

“I joined this lab just before the satellite project was handed over to JAXA, so the QPSK above ground software development was facing many obstacles to receive a greenlight to proceed. I was pleasured that I sent the first command to NEXUS after the launch. It was an incredible experience to listen to my own voice sent from outer space. I aim to be a software engineer in the future.”

● Miss Yuka Hirose (A 4th year bachelor’s degree student in charge of DQPSK Demodulation)
Was born in Tokyo, but her family relocated back to Yamaguchi prefecture when she was in high school. She was interested in astronomic and outer space, also in producing creative items for a long time. She was a newcomer to the NEXUS team and is responsible for DQPSK Demodulation this year. It was the first-time that she saw an actual transponder operation yesterday, which intrigued her even more to learn about how amateur radio enthusiasts remotely communicate with NEXUS. She may not pursue higher academic study, but would like to start her career by working for artificial satellite organizations.

QSL card of JS1YAW (Control station) and JS1YAV (NEXUS). Signal of NEXUS can be received globally, more than approximately 700 reports receiving worldwide

My first experience to communicate through a satellite!

As the short individual interviews came to end, it was almost time for NEXUS to pass overhead. Two gentlemen from JAMSAT, Mr. Kaneko (JA1OGZ) and Mr. Ueda (JA0FKM/1), who joined my tour today, help set up the IC-9700 from the JAMSAT Club station on the rack shelf. The antenna to be used for this operation was not the one that is used to control NEXUS.

Mr. Kaneko asked “Masaco, is this the first time for you to communicate through satellite?” “Yes, this is my first time ever,” I replied. He advised me “The way to communication through satellite is to repeat sending brief CQs several times. Call the targets as soon as “hello” or “yes” responded. You do not need to release the PTT button for standby.” My concern was that the receive frequency from satellite changes constantly. “How does it work to track the antenna?” I asked. “That is the part for us to take care of, he said with laughter. You only need to focus on the QSO. There is only up to 10 minutes of time for communication.” I happily said “Roger, thank you. Will there be a pile-up?” He explained “We have twitted information of that “NEXUS transporter has been set to ON” just now. People who have waited for this moment will target this orbit. So, Good luck!”

While I was setting up for QSO, CW signals of NEXUS could be heard from the IC-9100 control radio. I heard “Ok、let’s go!,” so I held IC-9700 microphone and started transmitting “CQ NEXUS, CQ NEXUS, this is JS1YAQ/1”.

My first experience of satellite operation with a JAMSAT club station, JS1YAQ. Simultaneously, Mr. Ueda of JAMSAT processed satellite tracking and minor adjusting for frequency accordingly.

During the middle of 3rd time of CQ, I heard someone answer…”JS1YAQ/1, this is JS3CTQ” My first contact….”JS3CTQ, you are 59 , over.” “JS1YAQ/1, you are 59 also very clear in Nara. Hello Masaco.” Oh wow, my first experience calling through a satellite.

After this first satellite QSO, I worked a total of 5 stations in the areas of JA3→JA3→JA0→JA8→JA1. I could also hear other stations calling CQ. While I was busy concentrating on copying callsigns of stations that called me, Mr. Kaneko showed me a cue card of the stations that he copied. I did not expect to be able to communicate through a satellite on this trip. Thank you so much!

All the staff members, and related professionals were watching closely at the satellite’s status during my QSOs.

With QRM sometimes, it was my first experience with satellite communications, and my first full duplex operation that brought me so much excitement. Until the end of my experience, all staff members of the Miyazaki lab watched closely after me all the time.

Many thanks to everyone in Miyazaki Lab, Department of Aerospace Engineering, College of Science and Technology, Nihon University, and Mr. Ueda and Mr. Kaneko san from JAMSAT.

I appreciate everyone in the Miyazaki Lab, Department of Aerospace Engineering, College of Science and Technology, Nihon University for spending such treasured time with me. I was impressed with “a star” created by you that has been orbiting the earth. The program that you created has been flying in space, and your own voice has been digitalized and sent back to earth from space. You are playing a part of the unlimited expanding future and helping to develop satellites that provide so much information. I imagined and shared the thrill of a moment when you tasted the fruit of all the efforts that you made to complete the satellite and successfully launch it into outer space.

Realizing an idea is one thing; to process such goal which full of unimaginable hardship and self-control emotionally is another. I trust that through your support of each other, and your consistent research, your connection with the universe will be closer every day. Please keep sharing your experiences and knowledge about satellite development with future generations. I wish another new satellite will be created by you soon.

Toward the end of my visit, I asked everyone “what kind of music do you listen to for relaxation?” “Pop songs from Showa era” was the reply. As a pop song singer, I was so thrilled to hear that, and felt a sense of closeness with everybody there. Music also is something that crosses and circles different generations.

(JH1CBX Masaco)

＜information＞
Please visit the websites for NEXUS and other amateur satellite communications. The NEXUS website contains a signal received report form.
・NEXUS http://sat.aero.cst.nihon-u.ac.jp/nexus/E0_Top.html
・JAMSAT https://www.jamsat.or.jp/ (Japanese)