Session
Advanced Technologies Research & Academia 2
Location
Salt Palace Convention Center, Salt Lake City, UT
Abstract
Large constellations of SmallSats in Low Earth Orbit (LEO) are now delivering critical capabilities for missions in Earth observation, navigation, and communications. Very Low Earth Orbit (VLEO), defined here as below 400 km altitude, is emerging as a new frontier for SmallSat constellations due to its unique advantages. VLEO offers improved spatial resolution for Earth observations, reduced latency, increased signal power, and a naturally self-cleaning orbital environment. However, operating spacecraft in VLEO is non-trivial as the spacecraft must overcome the residual atmosphere at these altitudes and the resulting increase in aerodynamic drag and atomic oxygen fluence. As interest grows in VLEO architectures, flight-validated aerodynamic models and improved orbit tracking approaches become increasingly crucial.
This research provides a flight-validation example of VLEO drag characterization and tracking improvement using the Laboratory for Atmospheric and Space Physics (LASP) Compact Spectral Irradiance Monitor (CSIM) CubeSat as it descends through VLEO altitudes. CSIM was commanded into distinct high-drag and low-drag configurations, enabling novel experimental measurement of aerodynamic force and torque effects relevant to CubeSat lifetime estimation, attitude stability, and maneuver strategy. These controlled operational modes provided a unique dataset for assessing how small satellites interact with the residual atmosphere at VLEO altitudes. On-orbit data was compared against leading aerodynamic modeling approaches, including MONACO, a Direct Simulation Monte Carlo (DSMC) framework, and VECTOR, a flat-panel analytical tool. Both methods showed excellent agreement overall; however, configurations with significant panel shadowing exhibit up to a 24% difference in predicted drag area product (������). Aerodynamic analyses also compared CSIM flight data with United States Space Force (USSF) Energy Dissipation Rates (EDRs), determining that surface energy accommodation values of 0.90–0.93 best match on-orbit observations.
In parallel, we demonstrated how observation architectures can improve orbit tracking for VLEO spacecraft. An Orekit sensitivity study showed that Doppler observations from a single ground station collected once per day reduce orbit error and uncertainty by an order of magnitude. Actual RF Doppler measurements for CSIM are processed using the Satellite Tracking Radio Frequency (STRF) toolkit, and Doppler-corrected orbital products are assessed against standard CSIM tracking solutions. Optical astrometry from the University of Colorado Boulder’s VaDeR laboratory telescopes further demonstrated the feasibility of determining on-sky orbit locations for CSIM despite limited illumination opportunities in its sun-synchronous, low altitude orbit. Our results motivate practical observation strategies that can be adopted by university and government operators seeking improved tracking of VLEO CubeSats.
Students played critical roles throughout this effort, including supporting CSIM mission operations, collecting data products, and performing key data analyses. This project provided hands-on, end-to-end training to prepare the next generation of engineers and scientists for CubeSat VLEO mission operations. Overall, by coupling atmospheric drag analysis with operational tracking improvements, this work delivers actionable, quantitatively supported recommendations for CubeSat operators and mission designers seeking sustained operations in the VLEO environment.
Document Type
Event
Analysis of Satellite Drag, Orbit Tracking, and Associated Operational Impacts in Very Low Earth Orbit (VLEO)
Salt Palace Convention Center, Salt Lake City, UT
Large constellations of SmallSats in Low Earth Orbit (LEO) are now delivering critical capabilities for missions in Earth observation, navigation, and communications. Very Low Earth Orbit (VLEO), defined here as below 400 km altitude, is emerging as a new frontier for SmallSat constellations due to its unique advantages. VLEO offers improved spatial resolution for Earth observations, reduced latency, increased signal power, and a naturally self-cleaning orbital environment. However, operating spacecraft in VLEO is non-trivial as the spacecraft must overcome the residual atmosphere at these altitudes and the resulting increase in aerodynamic drag and atomic oxygen fluence. As interest grows in VLEO architectures, flight-validated aerodynamic models and improved orbit tracking approaches become increasingly crucial.
This research provides a flight-validation example of VLEO drag characterization and tracking improvement using the Laboratory for Atmospheric and Space Physics (LASP) Compact Spectral Irradiance Monitor (CSIM) CubeSat as it descends through VLEO altitudes. CSIM was commanded into distinct high-drag and low-drag configurations, enabling novel experimental measurement of aerodynamic force and torque effects relevant to CubeSat lifetime estimation, attitude stability, and maneuver strategy. These controlled operational modes provided a unique dataset for assessing how small satellites interact with the residual atmosphere at VLEO altitudes. On-orbit data was compared against leading aerodynamic modeling approaches, including MONACO, a Direct Simulation Monte Carlo (DSMC) framework, and VECTOR, a flat-panel analytical tool. Both methods showed excellent agreement overall; however, configurations with significant panel shadowing exhibit up to a 24% difference in predicted drag area product (������). Aerodynamic analyses also compared CSIM flight data with United States Space Force (USSF) Energy Dissipation Rates (EDRs), determining that surface energy accommodation values of 0.90–0.93 best match on-orbit observations.
In parallel, we demonstrated how observation architectures can improve orbit tracking for VLEO spacecraft. An Orekit sensitivity study showed that Doppler observations from a single ground station collected once per day reduce orbit error and uncertainty by an order of magnitude. Actual RF Doppler measurements for CSIM are processed using the Satellite Tracking Radio Frequency (STRF) toolkit, and Doppler-corrected orbital products are assessed against standard CSIM tracking solutions. Optical astrometry from the University of Colorado Boulder’s VaDeR laboratory telescopes further demonstrated the feasibility of determining on-sky orbit locations for CSIM despite limited illumination opportunities in its sun-synchronous, low altitude orbit. Our results motivate practical observation strategies that can be adopted by university and government operators seeking improved tracking of VLEO CubeSats.
Students played critical roles throughout this effort, including supporting CSIM mission operations, collecting data products, and performing key data analyses. This project provided hands-on, end-to-end training to prepare the next generation of engineers and scientists for CubeSat VLEO mission operations. Overall, by coupling atmospheric drag analysis with operational tracking improvements, this work delivers actionable, quantitatively supported recommendations for CubeSat operators and mission designers seeking sustained operations in the VLEO environment.
