Phoenix CubeSat Satellite

Thermal imaging of cities to study spatial and temporal changes.

Demonstrate the effectiveness of nanosatellite platforms for studying spatial and temporal changes in the heat properties of urban environments by conducting a thermal imaging of the city of Phoenix and several others in the U.S. Utilize a 3U CubeSat architecture along with the incorporation of FLIR’s Tau2 640 IR camera to promote the study of the UHI Effect in LEO.

The heart of the spacecraft is its infrared imager, a commercial microbolometer from FLIR Technologies. This provides a resolution of 640x512 pixels. Fitted with a 100mm lens, it has a 5 degree by 6.2 degree field of view that covers an area 22 miles by 27 miles on the ground and provides a resolution up to 228 feet per pixel.

Phoenix's beacon was heard for the first time at a ground station located in Indonesia. Amateur operators continued to hear its health beacon throughout the day by tracking the ISS, including the Phoenix operations team, using the ASU ground station. The team was also able to perform a successful schedule uplink to collect more telemetry from the ADCS, which marked the first CubeSat operation from the university!
Since deployment day, it has been difficult to hear from the spacecraft. During Phoenix's last pass of the day over the ASU ground station, the spacecraft went into an error state, which we believe depleted the battery below the voltage cutoff level. This would have cut power to the rest of the hardware, preventing the Phoenix from transmitting its health beacon, responding to our commands, or tracking the sun to generate more power. 
It was discovered that while the AX100 transceiver was operational, the OBC did not respond to any packets beyond short ping commands. Further, ping communication only occurred successfully during daytime passes. This suggested that Phoenix was likely not tracking the sun using the ADCS, preventing the battery from charging sufficiently to power the spacecraft during eclipses.
Upon further investigation into the error state, the anomalous stream of packets was linked to a syn-ack packet flood. Benchtop testing with an engineering model of the AX100 transceiver and conversations with the vendor indicate that a single bit flip in the packet checksum could have enabled the Reliable Data Protocol (RDP). This would have introduced the syn-ack stream in an effort to verify a link between the ground station and the spacecraft, resulting in a gradual drain of the battery level. However, while the packet stream issue is considered resolved, it is still unclear as to why we can only receive CSP ping packet responses from the OBC after the power reset. 
Although Phoenix’s science objective was not achieved, the spacecraft can still be utilized for other purposes. The ability to conduct two-way communications allows the spacecraft to be useful for calibrating ground stations to communicate with CubeSats in LEO. 

• AeroCube-14A
• AeroCube-14B
• AeroCube-15A
• AeroCube-15B
• HARP
• HuskySat-1
• MVP Argus
• Orbital Factory II
• Phoenix CubeSat
• RadSat-u
• SOCRATES
• SwampSat II