TBEx Launched, Deployed, and Operational


by Andrew Stephenson and MXL.

The two TBEx satellites launched in June 2019 will give scientists detailed insight into the effects of plasma bubbles in the upper atmosphere and how this space weather impacts space communication.
A SpaceX Falcon Heavy launching from Kennedy Space Center.
A SpaceX Falcon Heavy rocket carrying 24 satellites as part of the Department of Defense’s Space Test Program-2 (STP-2) mission launches from Launch Complex 39A, Tuesday, June 25, 2019 at NASA’s Kennedy Space Center in Florida. Four NASA technology and science payloads which will study non-toxic spacecraft fuel, deep space navigation, “bubbles” in the electrically-charged layers of Earth’s upper atmosphere, and radiation protection for satellites are among the two dozen satellites that will be put into orbit. Photo Credit: (NASA/Joel Kowsky)

On June 25, 2019, two CubeSats developed by the Michigan Exploration Laboratory (MXL) were deployed in low Earth orbit by a SpaceX Falcon Heavy rocket. These satellites, called the Tandem Beacon Experiment (TBEx), are part of a NASA project to understand unpredictable plasma bubbles that form in the upper atmosphere and how they impact communications. The launch was funded by the US Space Test Program.

During their year-long mission, the TBEx satellites will send radio signals to ground stations and the world, which will measure the distortions caused by the plasma bubbles. Signals such as GPS transmissions are distorted unpredictably when they pass through the ionospheric plasma bubbles.

MXL worked with SRI International to develop the TBEx mission for NASA. MXL developed the satellite system and the payload was developed by SRI International. Graduate students Prince Kuevor who works at MXL, and Paul Knudsen who runs the TBEx operations from MXL’s control center, spoke about the design challenges they faced. Both cited the complex antennas, which are packed for the launch and deployment when the satellite is in orbit, as the biggest challenge. The satellites were also equipped with an advanced attitude control system built in-house, a first for MXL.

MXL is run by Associate Professor James Cutler who led graduate and undergraduate students to design, build, test, and fly the TBEx satellites. As students graduate and take their experience and expertise with them, new engineers must be trained to carry on the work. “Test regularly and write things down” is the philosophy of Kuevor, who joined MXL as a sophomore and is now working on his PhD. Kuevor sees MXL as a good source of experience and inspiration for these students: “[The Laboratory] is a great way to get young, interested, and innovative minds involved in this field.”

Over the next year, the MXL team will coordinate TBEx flight experiments with additional satellites developed by NOAA, six COSMIC-2 satellites. Together, as a constellation of small satellites, they will explore plasma bubble evolution and development over time. The use of CubeSats as large-scale constellations is at the forefront of space research, and these MXL students are leaders in this global CubeSat effort.