LightSail starts sending data; all systems said to be nominal

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The Planetary Society’s LightSail spacecraft which was launched and deposited into space on May 20 has started sending data back to mission control and it seems that all is well with the spacecraft.

According to The Planetary Society, a total of 55 beacon packets have been downloaded thus far with each of the packets containing vital information on the health of the spacecraft and trends from data will start to emerge as more and more data is downlinked.

Shortly after the ground pass began, Cal Poly detected LightSail’s automated radio chirps. Jason Davis, Digital Editor at The Planetary Society, tweeted: “Cal Poly thinks they see our signal! #LightSail RF signal with 15-second cadence!”

Once the telemetry data was decoded, the first impressions were that most values were nominal or near predicted ranges. However, there was a concern wherein a line of telemetry data showing the indicator switches for solar panel deployment have been triggered. According to the Society, under normal circumstances, the solar panels do not open until the sail deployment sequence starts, because the sails have a tendency to start billowing out of their storage cavities.

The organisation was quick to add that the readings do not necessarily mean the panels are open. There has been an instance before when switches were inadvertantly triggered during vibration testing, so it’s possible they popped loose during the ride to orbit. The Planetary Society added that they will know for sure after flight day four, when we test out the camera system.

The Planetary society also revealed that a two-way communications has been established with LightSail after which the spacecraft was commanded to turn off its gyroscopes, which measure the effect of solar sail deployment on the vehicle. These gyroscopes were turned on after P-POD deployment, causing a higher-than-average power drain on the spacecraft’s batteries. Telemetry downloaded after the command was sent showed the gyroscopes are now off. Later analysis showed they were “left on” in the spacecraft’s software sequence—a condition that will be changed for the 2016 mission.

A temperature sensor on one of LightSail’s circuit boards has ranged from seven to 26.5 degrees Celsius as the spacecraft zips around the Earth, moving in and out of darkness.

On Sunday, LightSail’s cameras will capture their first test images and that is the time when mission control will find out if the solar panels have been deployed or not. If the panels haven’t been deployed, which is what the mission control wants, they won’t see anything except the inside of the spacecraft.