Tucson Standard

Scientists and engineers at the University of Arizona have built instruments for three NASA telescopes, led two deep space missions and made it possible to see farther back in space and time than ever before. Adding to this list of space exploration accomplishments is a different type of project – one led entirely by students.

Near the university's main campus, students gather inside a cleanroom wearing lab coats, gloves and hairnets. On their lab bench sits a complex maze of wires and metal, the dimensions of a family-size cereal box. Each component has been optimized to survive a rocket launch and orbit the Earth.

After years of designing, building and testing, a team of UArizona students has readied CatSat, a small satellite known as a CubeSat, for launch into space. The spacecraft was designed to demonstrate new space technology and overcome a major challenge in space exploration: high-speed, low-cost communication across vast distances. Reminiscent of a beach ball, the satellite's antenna is expected to transfer information from space to Earth at high data rates.

If everything goes according to plan, the satellite won't just demonstrate new space technology; it will also probe the ionosphere – a layer of charged particles at the boundary between the Earth's atmosphere and space – so that the team can better understand the ionosphere's ever-changing structure. This structure impacts the propagation of high-frequency radio signals.

CubeSats are miniature cube-shaped satellites that orbit Earth and range in size from a 10-centimeter cube to a desktop computer. CubeSats are made with modular, relatively low-cost components, allowing many universities and other educational institutions to get involved in space exploration.

CatSat is a so-called 6U CubeSat, meaning it consists of six conjoined cubes, each measuring 4 inches along their edges. Unlike other CubeSats, it has an inflatable antenna, developed by Freefall Aerospace, a Tucson-based startup company and spinoff that was brought to be with the help of the university's commercialization arm, Tech Launch Arizona. Stored inside of CatSat is a high-performance, software-defined radio named AstroSDR, which was designed, built and donated by Rincon Research Corporation. After launch, the inflatable antenna, AstroSDR and other components will work together to send down high-resolution images of Earth almost instantaneously.

"Following a successful launch, this inflatable antenna will be the first of its kind in space," said Hilliard Paige, a systems engineering student and the project's lead systems engineer. "If it works, it will be a pathfinder for future missions."

The project began in 2019 when Chris Walker, a UArizona professor of astronomy, along with a team of faculty members from other departments, submitted a proposal to NASA as part of the NASA CubeSat Launch Initiative. NASA saw potential and agreed to provide a launch vehicle for CatSat.

"The technology demonstrated by CatSat opens the door to the possibility of future lunar, planetary and deep-space missions using CubeSats," said Walker, who also is the co-founder of FreeFall Aerospace. "CatSat puts the University of Arizona at the forefront of these efforts."

Inflatable antennas could give an edge to small spacecraft

All spacecraft require antennas to transmit and receive signals, allowing for communication with Earth. Yet, the capabilities of CubeSat antennas have historically been restricted, as CubeSats can only carry very small antennas. Signals from these small antennas can take days to finally reach Earth.

CatSat's inflatable antenna, invented by Walker at UArizona and further developed by Freefall Aerospace, combats this problem thanks to its lightweight material that tightly folds within the spacecraft. After launch, CatSat will stabilize its orientation so that it can eventually deploy the stowed antenna membrane and inflate it with helium and argon gas.

This inflated membrane is not unlike a large, floating foil birthday balloon. It has a clear lower hemisphere and an aluminum-coated upper hemisphere designed to reflect signals back down to Earth. The antenna's large surface allows for downlink speeds many times faster than comparable CubeSats.

Freefall Aerospace and the CatSat student team hope that inflatable antennas could level the playing field, allowing smaller and cheaper spacecraft to explore places beyond Earth.

"This technology could drive down the cost of high-quality scientific measurements in space by enabling the use of lightweight, low-cost antennas with very high data rates," said Aman Chandra, a doctoral student in mechanical engineering who is responsible for much of CatSat's mechanical design, including the inflatable antenna system. 

Scientific exploration of the ionosphere

On the opposite end of CatSat's inflatable antenna is a "whip" antenna, about 2 feet long and shaped like a protruding stick. It was designed to receive low-power, automated, high-frequency beacons from thousands of Earthbound amateur radio enthusiasts. Radio signals in the high-frequency range can bounce off or refract from the ionosphere and travel to far-reaching locations by "bending around the Earth." Amateur, or ham, radio takes advantage of this charged layer of the atmosphere to broadcast information all around the globe.

Original source can be found here.