Science Mode

Objectives

ArcticSat science mode analysis was performed using the ArcticSat attitude simulator. The objectives of this analysis are:

1. Design the maneuvers for transition between data collection and non-data collection without sacrificing solar illumination (R-ARC-ADC-057).

2. Determine how accurately ArcticSat can maintain a 50 degree slant angle from nadir for data collection (R-ARC-ADC-041)(R-ARC-ADC-071).

3. Determine the power consumption of maneuvers.

Simulation Setup

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: 30 deg

The maneuver involves moving into data collection orientation from the non-data collection orientation which has the long axis of the satellite pointing in the ram direction. From the ram orientation, it slews the payload 40 degrees toward nadir to establish the required slant angle, then slews back to ram-pointing after leaving the data collection area.

Controllers

Science mode uses a fine pointing controller and a rate controller in tandem to maintain the desired attitude. The rate controller applies a small torque equal to the satellite's orbital angular velocity to maintain the satellite's orientation relative to the Earth, and the fine pointing controller handles the precise pointing of the payload. 

Simulation Results

It can be seen in the figure above that ArcticSat is able to maintain a 50 degree slant angle, and the state of charge figure shows that the entire maneuver is power positive.

Furthermore, the above plots show that the maneuver is power positive overall.