TY  - GEN
AB  - The University of Southern Indiana (USI) Undergraduate Nano Ionospheric Temperature Explorer (UNITE)
CubeSat, funded by NASA’s Undergraduate Student Instrument Project – 2 (USIP-2), was deployed from the
International Space Station on January 31, 2019 (Figure 1). UNITE was a 3U CubeSat without deployables that
was passively stabilized magnetically and aerodynamically. The UNITE CubeSat reentered the atmosphere on
October 21, 2021, its 995th day in orbit. One of the mission objectives of UNITE was to track its orbital decay with
the intent of updating CubeSat drag models. The original predicted mission lifetime of 428 days was based on results from a spreadsheet available with Space Mission Engineering: The New SMAD, using standard CubeSat parameters and simply assuming “solar mean” for the solar cycle. To more accurately understand the actual orbital behavior known from the TLEs (two-line elements), a 
 completely new algorithm was coded for orbital drag, but taking into account varying atmospheric densities consistent with the variability of the actual solar cycle experienced between January 2019 and October 2021. Using the algorithm and the updated atmospheric density model, the
mission time was computed to be 976 days, only 19 days short of the actual mission time. Next, the drag coefficient was adjusted from 2.2 to 2.08, and with that change the algorithm correctly calculated the 995 days in orbit. Also of note, in the process o f the development of the algorithm, a slight error was discovered in the Bessel function table available through The New SMAD, and that was corrected, as well. The new algorithm, developed by the undergraduate student, was implemented in an Excel program and is readily
available for use by other teams. With the implementation of a new algorithm that accounts for solar cycle activity and allows for drag coefficient adjustment, it is hoped that future CubeSat teams will be able to predict mission life and the orbital decay more accurately.
AD  - University of Southern Indiana
AU  - Davis, Charles Clayton
DA  - 2023-04-27
DO  - 10.58090/usi.1461080
DO  - doi
ID  - 1461080
KW  - UNITE
KW  - CubeSat
L1  - https://library.usi.edu/record/1461080/files/Lessons%20Learned%20About%20Orbital%20Decay%20from%20the%20UNITE%20CubeSat%20Poster%20%282%29.pdf
L2  - https://library.usi.edu/record/1461080/files/Lessons%20Learned%20About%20Orbital%20Decay%20from%20the%20UNITE%20CubeSat%20Poster%20%282%29.pdf
L4  - https://library.usi.edu/record/1461080/files/Lessons%20Learned%20About%20Orbital%20Decay%20from%20the%20UNITE%20CubeSat%20Poster%20%282%29.pdf
LA  - eng
LK  - https://library.usi.edu/record/1461080/files/Lessons%20Learned%20About%20Orbital%20Decay%20from%20the%20UNITE%20CubeSat%20Poster%20%282%29.pdf
N2  - The University of Southern Indiana (USI) Undergraduate Nano Ionospheric Temperature Explorer (UNITE)
CubeSat, funded by NASA’s Undergraduate Student Instrument Project – 2 (USIP-2), was deployed from the
International Space Station on January 31, 2019 (Figure 1). UNITE was a 3U CubeSat without deployables that
was passively stabilized magnetically and aerodynamically. The UNITE CubeSat reentered the atmosphere on
October 21, 2021, its 995th day in orbit. One of the mission objectives of UNITE was to track its orbital decay with
the intent of updating CubeSat drag models. The original predicted mission lifetime of 428 days was based on results from a spreadsheet available with Space Mission Engineering: The New SMAD, using standard CubeSat parameters and simply assuming “solar mean” for the solar cycle. To more accurately understand the actual orbital behavior known from the TLEs (two-line elements), a 
 completely new algorithm was coded for orbital drag, but taking into account varying atmospheric densities consistent with the variability of the actual solar cycle experienced between January 2019 and October 2021. Using the algorithm and the updated atmospheric density model, the
mission time was computed to be 976 days, only 19 days short of the actual mission time. Next, the drag coefficient was adjusted from 2.2 to 2.08, and with that change the algorithm correctly calculated the 995 days in orbit. Also of note, in the process o f the development of the algorithm, a slight error was discovered in the Bessel function table available through The New SMAD, and that was corrected, as well. The new algorithm, developed by the undergraduate student, was implemented in an Excel program and is readily
available for use by other teams. With the implementation of a new algorithm that accounts for solar cycle activity and allows for drag coefficient adjustment, it is hoped that future CubeSat teams will be able to predict mission life and the orbital decay more accurately.
PY  - 2023-04-27
T1  - Lessons Learned About Orbital Decay from the UNITE CubeSat
TI  - Lessons Learned About Orbital Decay from the UNITE CubeSat
UR  - https://library.usi.edu/record/1461080/files/Lessons%20Learned%20About%20Orbital%20Decay%20from%20the%20UNITE%20CubeSat%20Poster%20%282%29.pdf
Y1  - 2023-04-27
ER  -