Magnetometer calibration

Last year, LightSail 2 completed an extensive set of magnetometer calibrations and attitude control tests at Utah State University's Space Dynamics Laboratory and the UCLA Institute of Geophysics and Planetary Physics.

LightSail orients itself in space using a set of electromagnetic torque rods that push against Earth's natural magnetic field. The spacecraft reads the strength and direction of that field—which varies around the world—using magnetometers mounted at the end of each deployable solar panel.

Those magnetometers are factory-calibrated, but a spacecraft’s electronics also generate magnetic fields. Therefore, the magnetometers must be calibrated again after installation.

When LightSail's solar panels are closed, the magnetometers sit right next to the spacecraft’s solar sail deployment motor. The motor spindle has six magnets attached to it, and every time the motor spins, the magnets end up in a slightly different position

After LightSail's final boom deployment test, during which the motor spun for the final time before solar sail deployment in space, the spacecraft went back to UCLA for a final magnetometer calibration.

"We don't have a way of precisely stopping the motor in the same position every time," said Alex Diaz, a LightSail engineer at Ecliptic Enterprises Corporation. "So, being that we aren't going to move the motor any more, we went ahead and did a calibration."

Prox-1 mission change

In late May, LightSail 2's partner spacecraft, Prox-1, shipped to the Air Force Research Laboratory in Albuquerque, New Mexico.

Prox-1 is a Georgia Tech student-built SmallSat sponsored by the Air Force's University Nanosat Program, or UNP. LightSail 2 and Prox-1 are booked as secondary payloads on the Air Force’s STP-2 mission, which will launch on a SpaceX Falcon Heavy rocket.

Prox-1's original mission plan was to deploy LightSail 2, track it down, and image it during solar sail deployment.

In Albuquerque, the UNP and Prox-1 teams conducted a review of the spacecraft, and determined that while the hardware needed for the mission was fully integrated, the flight software required further development.

"After discussions between the Air Force and Nanosat program, the two programs decided to scale back some of Prox-1 mission objectives," said Dave Spencer, LightSail 2’s project manager.

As part of the change, Prox-1 will still deploy LightSail 2, but not track the solar sail CubeSat down and image it during sail deployment. None of LightSail 2’s mission objectives have changed, and fortunately, the spacecraft has its own onboard cameras, which the LightSail team will use to image the solar sail deployment sequence.