ArcticSat detumbling analysis was performed using the ArcticSat attitude simulator. The objectives of this analysis include:
The total duration of a complete detumbling maneuver from deployment (R-ARC-ADC-021).
The total power consumption of the detumbling maneuver.
Identify potential anomalies to be analyzed further in flight software(R-ARC-ADC-026).
Test transition to sun-pointing after successfully detumbling (R-ARC-ADC-035).
As a result, the simulation was set up to represent a worst-case scenario for the metrics we are investigating. ArcticSat will deploy from a 4U EXOpod Nova. Exolaunch reports tip-off rates for all deployments stay below than 10 deg/s in all axes, but 3U CubeSats tend to be more stable. Based on this, initial body rates were chosen to be 6 deg/s in the x- and z-axes in the body frame, and 2 deg/s in the y-axis.
ArcticSat will have the least power generation capability around the summer solstice, when it spends the most time in eclipse, so this deployment time was chosen to investigate. Time and orbit details can be found below.
Epoch: 21 June 2025 12:00:00 UTC
Altitude: 525 km
Inclination: 97.5 deg
RAAN: 180 deg
Arg. Perigee: 0 deg
True Anomaly: 0 deg
Detumbling mode uses a B-dot controller which calculates a filtered derivative of the magnetic field and commands a torque in the opposite direction using ArcticSat's magnetorquers. The only sensors used are the magnetometer and gyroscope, and the only actuators used are the magnetorquers. Control commands operate on a 70% second duty cycle (the magnetorquers are activated for 0.7 seconds out of every second) to give the magnetometer time to collect data for the derivative calculation.
The results of this simulation show that ArcticSat successfully detumbles after about 80 minutes, which satisfies R-ARC-ADC-021. The total depth of discharge on the battery after detumbling was found to be approximately 6%.
Orbit animation of ArcticSat detumble simulation. Time has been sped up 100x.
Normalized body rates from detumbling maneuver.
Battery state of charge during detumbling.
It can be seen around 3000 seconds in the body rate plot that the spacecraft seems to come to a constant, low spin rate before entering more of an unstable spin, then returning to another constant rate approaching 5000 seconds. This anomaly should be analyzed and tested on flight hardware as per R-ARC-ADC-026.