LightSail is back in business, following the second extended outage of the test spacecraft’s mission. The CubeSat checked in at 2:21 p.m. EDT (18:21 UTC) Saturday for the first time since Wednesday afternoon. Over the course of two overflights, 23 beacon telemetry packets were received by the spacecraft's Cal Poly San Luis Obispo ground station.
A rapid sail deployment was briefly considered, but with battery levels still unsteady and just one ground pass remaining before an eight-and-a-half hour outage, the team scrapped the idea. When LightSail came around the Earth again, telemetry showed its batteries were charging—the first time since solar panel deployment three days ago.
If battery levels continue to trend stably during Sunday’s early morning ground station passes, sail deployment will be scheduled for 2:02 p.m. EDT (18:02 UTC).
Engineers have been working to narrow down the reason LightSail’s batteries tripped into a safe mode-like condition following solar panel deployment. Before this afternoon's signal acquisition, the leading theory was that the spacecraft was stuck in a loop where power levels were too low in Earth's shadow, but too high in sunlight. This power ping-pong could have prevented the batteries from reattaching their circuits to the spacecraft and allowing normal operations to resume. The analysis is still ongoing.