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CubeSat: High School Satellite

CubeSat: High School Satellite

Bringing High Schools to Space

Justin Zhou

Thomas Jefferson High School for Science and Technology

This article was originally included in the 2018 print publication of Teknos Science Journal.

Space feels like an abstraction, something reserved for PhDs and astronauts. The “final frontier” certainly seems out of reach for a mere high school student like myself, and yet, I can walk to my senior research lab, the Energy Systems Lab, and hold a satellite in the palm of my hand. This satellite is not a watered down model intended for students to get a glimpse of the space industry. This is the TJ REVERB CubeSat. In September, this nanosatellite mission will be delivered to Nanoracks, a launch preparation company, that will package our satellite in a deployer to be handed over to NASA. A resupply rocket will transport it to the International Space Station, where it will be deployed a few months later. This little box, a little smaller than a loaf of bread, is headed for space. The mission was designed by a group of us in 2016 with the help of our advisor and industry mentors. Now we’re building it and working with more mentors to test it. I feel I was part of this from the beginning and us high school students are taking on real engineering roles and able to do something few students have done.

Traditionally, satellites are massive affairs. They can take up to a decade to design and cost millions of dollars just to launch into orbit. The largest satellite that NASA launched was the Cassini planetary exploration mission in 1997, which weighed a whopping 5.7 tons. Satellites were large because engineers believed they could  merge multiple mission concepts into one package. In this way, space agencies could avoid launching multiple satellites and reduce launch costs. In reality, complex satellites elongated the developmental cycle because engineers had to work around more points of failure.Realizing this, the industry began trending toward smaller, simpler missions. Advances in microelectronics allowed for smaller satellites to have more functionality using commercial, off-the-shelf parts (COTS). In 1999, Stanford and the California Polytechnic State Universities created the standard CubeSat, a satellite that could fit in a 10-centimeter cube. CubeSat missions generally took only a couple years to develop and could be built for less than $100,000, as opposed to traditional multi-million dollar missions. These satellites opened the door for educational institutions and small companies to reach space, a plane once thought to be reserved for governments and multinational corporations. CubeSats have been used for everything from satellite Internet access to deep space exploration (Poghosyan & Golkar, 2017). The proliferation of small, cheap satellites has also made more feasible the concept of satellite constellations, whole networks of satellites that can be used for telephone communications and climate research (Crisp, Smith, & Hollingsworth, 2015).

TJHSST has been designing its second CubeSat mission since May 2016. While we became the first high school to launch a satellite into orbit in 2013, we failed to communicate with the satellite. While we are not sure as to why the failure occurred, it is important to note that CubeSats typically fail half the time regardless of the quality of design. The current mission, named the Thomas Jefferson Research and Education Vehicle for the Evaluation of Radio Broadcasts (TJ REVERB) was awarded the NASA CubeSat Launch Initiative (CSLI) grant in 2017, which provides a free launch into low-earth orbit (LEO). The purpose of the mission is build an educational communications guide for others to use. We’ll be testing the coverage rate and feasibility of using Iridium satellite network on CubeSats in Lower Earth Orbit, as well as testing an Automatic Packet Reporting System (APRS) radio. As such, the payload of the TJ-REVERB is the Iridium 9603 Modem and a specially designed VHF radio. To date, only government-built satellites have used these communications systems in low earth orbit. We also studying the possibility of using the Near Earth Network. By testing these systems, we hope to set a precedent for future missions to have more flexibility in choosing their communications systems. As one of the systems engineers of the TJ REVERB mission, I am tasked with managing the satellite hardware assembly process and some of the testing procedures. Using computer-aided design software like Autodesk Fusion 360, I ensure that all of our components are arranged correctly within the satellite chassis.

Deceptively simple from the outside, the task of deciding what order we stack our components in the CubeSat is incredibly nuanced. We have to keep our center of mass within two centimeters of the center of the chassis, per our deployer’s requirements. We also want to position our center of mass over our magnetorquers, a series of electromagnets that interacts with the Earth’s magnetic field to allow us to control the satellite orientation. By placing the center of mass over the magnetorquers, we maximize our pointing ability (Gerhardt, 2016). This is especially important immediately after deployment from the ISS. CubeSats can spin up to 15 degrees per second after they’re deployed and magnetorquers are used to stabilize the CubeSat (S. Corpino, personal communication, Jan. 15 2018). Other considerations such as static interference and thermal conductivity inform how we arrange components in our CubeSat.

Our team will also oversee and document the TJ REVERB testing procedures before we deliver it to our deployer. The most critical testing procedures will be our vibration tests and thermal vacuum tests, which shows how our electronics will survive launch and perform in orbital conditions. The greatest risk is electronics failure, as similar CubeSat missions have failed to return readable telemetry data due to low power states (Corpino, Obiols-Rabasa, & Mozzillo, 2016). After documenting our testing procedures, our findings will be published online for other novice CubeSat builders to reference. Currently, nearly half of all satellites launched by first-time builders fail once they reach orbit (Poghosyan & Golkar, 2017). With more documentation online, TJHSST will contribute to making these missions more successful overall.

Since their inception, CubeSats have democratized space. In February 2017, the Indian Space Research Organization released over a hundred CubeSats into LEO. To date, over 700 CubeSats have made it to orbit (David, 2017).

Should the TJ-REVERB CubeSat mission succeed, TJHSST will be blazing new trails in the space industry. Not only would the TJ REVERB be the first high school CubeSat group to launch two satellites in which students have been integral to the designs, but it would also pave the way for future CubeSat missions to make use of the Iridium and NASA Near Earth Network communication systems. We hope that our efforts will spur other high school students to think big and design bigger as they dream up their own missions to the stars.

References

Corpino, S., Obiols-Rabasa, G., Mozzillo, R., & NicheleActa Astronautica, F. (2016). E-st@r-I experience: Valuable knowledge for improving the e-st@r-II design. Acta Astronautica, 121. https://doi.org/10.1016/j.actaastro.2015.12.027

Crisp, N. H., Smith, K., & Hollingsworth, P. (2015). Launch and deployment of distributed small satellite systems. Acta Astronautica, 114. https://doi.org/10.1016/j.actaastro.2015.04.015

David, L. (2017, July 12). Sweating the small stuff: CubeSats swarm earth orbit. Retrieved January 15, 2018, from Scientific American website: https://www.scientificamerican.com/article/sweating-the-small-stuff-cubesats-swarm-earth-orbit/

Gerhardt, D. (2016). GOMX-3: Mission results from the inaugural ESA in-orbit demonstration cubesat [White paper]. Retrieved January 12, 2018, from Utah State University website: https://digitalcommons.usu.edu/cgi/viewcontent.cgi?referer=http://davidgerhardt.com/publications/conference/&httpsredir=1&article=3347&context=smallsat

Poghosyan, A., & Golkar, A. (2017). CubeSat evolution: Analyzing cubesat capabilities for conducting science missions. Progress in Aerospace Sciences, 88. https://doi.org/10.1016/j.paerosci.2016.11.002


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