Large, traditional satellites require complex systems and often a dedicated launch vehicle to place them in orbit. The immense costs associated with these endeavors have led to growing demand for cost effective “nanosatellites.” In the past, small satellites may have been launched from rockets as “piggyback satellites” during various stages of ascent. But as these satellites become smaller and smaller, it is more feasible to transport them as cargo, give then an inspection, and launch them at the most opportune time from the security of a space station. This is also safer for the launch vehicle, reducing the complexity of managing both the main and tertiary satellite’s launch timing and positioning.
These cheap and efficient nanosatellites have become a mainstay of space agencies across the globe. Over 29 U.S. states have contributed nanosatellites from various scientific and educations organizations as of August this year. NASA is broadening the CubeSat Launch Initiative to promote industrial and educational partnerships and is hoping to launch 50 small satellites from 50 states within five years.
A multitude of various companies are innovating and adapting to meet that demand, including Monroeville, NC-based CRP USA. The company focuses in the American stockcar racing and additive manufacturing markets. However, their latest and most innovative project, TuPOD, is a completely 3D-printed satellite. It was the first to be launched from the International Space Station (ISS)—from the Japan Aerospace Exploration Agency (JAXA) Japanese Experimentation Module (JEM)—and sets the stage for a new era of small, reliable, additively manufactured satellites.
The TuPOD project began when Brazilian students from Escola Municipal Presidente Tancredo de Almeida Neves approached Italian G.A.U.S.S. Srl (Group of Astrodynamics for the Use of Space Systems) for assistance in overcoming ISS launch requirements for their TANCREDO-1 nanosatellite.
Their nanosatellite, classified as a “TubeSat,” was the approximately 9 X 13 cm—close to the size and shape of an aluminum can. TANCREDO-1 was so small that it was not compatible with the ISS’s normal CubeSat deployer—the Poly-Picosatellite Orbital Deployer (P-POD). GAUSS was tasked with developing a way to address the rigid mechanical properties of spacecraft construction while side-stepping the traditional tooling limitations associated with working on such a small device.
A TuPOD (Tubesat-POD) nanosatellite was developed to address the issue.
TuPOD design and testing
The TuPOD satellite is basically a 3U CubeSat with a deployment platform for two smaller TubeSats. CubeSats are a class of nanosatellites that are built to standard dimensions (Units or “U”) of 10 X 10 X 11 cm and typically weigh less than 3 lb per U. They can range from 1U to 6U in size.
GAUSS teamed with California-based Teton Aerospace, LLC (Tetonsys), whose co-founder founded CubeSat, the company that standardized CubeSat use for low Earth orbit (LEO) scientific use. GAUSS also teamed with CPR USA and Morehead State University. The group decided to pursue an additive manufacturing approach to address the stringent design challenges. The flexibility of additive manufacturing allowed the team to make design improvements and circumvent limitations of traditionally tooled designs without negatively impacting the development timeline or budget.
TuPOD was fully printed out of CRP USA’s proprietary carbon fiber reinforced composite material, Windform XT 2.0. The material, which is laser sintered, was originally developed by CRP USA’s partner CRP Technology, based in Modena, Italy, for use in Formula One Racing. Because of that, the material can withstand extreme vibrations whether from terrestrial engines or ascent engines. It also meets NASA spacecraft material guidelines for offgassing. Gasses trapped in materials during the manufacturing process may be released when that material enters a vacuum; those gasses present a potential hazard if they condense on optical elements or solar cells.
Windform XT 2.0 also allowed the team to easily make changes to the TuPOD design after it was printed.
“Using Windform XT 2.0 material in the 3D manufacturing of TuPOD was one of the best decisions we have ever made," said Amin Djamshidpour, designer of TuPOD. "During the prototyping phase and even during final manufacturing, we got into multiple situations where we needed to drill parts or make small modifications to the 3D printed structure, working with Windform XT 2.0 gave us the ability to do so.”
In addition to the Windform XT 2.0 “tube,” the design also included four external anodized aluminum alignment rails to square TuPOD’s shape. The ISS P-POD can only safely deploy satellite payloads that have a shape that aligns to the deployer’s square internal arrangement. Altogether, the total composite and aluminum material weighed 40% of what an equivalent completely aluminum structure would have weighed. With this weight reduction, the TuPOD essentially became a lightweight sheath for two TubeSats: TANCREDO-1 from the Brazilian students and OSNSAT, which was developed by California’s Open Space Network.
The end design of TuPOD resulted in a nanosatellite that was a manufactured as a unique single-part. After completion of the electronic board—which was also a feat of additive manufacturing where designers were able to combine the previous two-board design into one board—TuPOD was sent to Morehead State University for final vibration and thermal vacuum testing. TubeSat integration was then performed at GAUSS in Italy, then the package was taken to Ibaraki Prefecture, Japan where it was loaded into a JAXA JEM Samll Satellite Orbital Deployer (J-SSOD).
Success and looking ahead
The J-SODD deployer (containing TuPOD), was installed inside the autonomous Kounotori 6 H-IIB launch vehicle. TuPOD ascended December 9, 2016. Six weeks later the TuPOD was successfully launched from the ISS JEM “Kibo.” It deployed TANCREDO-1 and OSNSAT approximately 83 hours into its orbit. TuPOD then transmitted a signal beacon for four days, up until successful mission completion, when it deorbited and burned up upon re-entry to Earth’s atmosphere.
TuPOD allowed the new, never-before tested TubeSats to be deployed from existing JAXA CubeSat launch infrastructure on the ISS. Previously, there was no technology available to launch satellites as small as the TubeSats.
Chantal Cappelletti, GAUSS Project Manager, said, “During the mission, Windform XT 2.0 has passed all the flight qualification tests in complex systems as the International Space Station is. This achievement, unimaginable until recently, opens many perspectives on the possibility of using Windform materials for space applications. In particular, GAUSS Srl is more than satisfied with the selective laser sintering technique and considers the Windform family of high-performance composite materials one of the disruptive revolutions in the small satellites arena. Plus, GAUSS is using them for new projects.”
The innovations made in support of nanosatellite technology will increase return on investment of the space station deployers; they will enable more universities, companies, and other non-traditional space users to have affordable access to space research. Furthermore, the high reliability and high economic feasibility of this class of satellites, coupled with the ability to manufacture them through additive processes comes right as NASA selects companies to develop “FabLab” prototypes for in-space manufacturing suites.
With additively manufactured satellites and robust materials proven and available, the ability to manufacture, repair, and recycle items in space is right around the corner. These key technologies are quickly unlocking the barriers to longer range and sustainable human spaceflight missions.