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Jason DavisJuly 19, 2019

LightSail 2 Sail Deployment Scheduled for Tuesday

The Planetary Society's LightSail 2 spacecraft is almost ready to go solar sailing. 

Mission officials today cleared the spacecraft for a possible sail deployment attempt on Tuesday, 23 July 2019, during a ground station pass that starts at roughly 11:22 PDT (18:22 UTC). A backup pass is available the following orbit starting at 13:07 PDT (20:07 UTC). These times may change slightly as new orbit predictions become available. 

Live sail deployment coverage will be available at A video and audio stream from mission control, located at Cal Poly San Luis Obispo in California, will be available during ground station passes. Rolling updates will also be posted on the page for context.

On 17 July, flight controllers placed LightSail 2's attitude control system into solar sailing mode for a second time, allowing it to track the Sun and make two 90-degree turns into and away from the solar photons. When the solar sail has been deployed, these turns will raise one side of the spacecraft’s orbit.

An initial review of data from the test showed LightSail 2 performed as expected. A more thorough review is scheduled for Saturday, and on Sunday, the spacecraft will be placed in solar sailing mode a third time as a final verification that it is ready for sail deployment. 

Pacific Ocean and Mexico from LightSail 2

The Planetary Society

Pacific Ocean and Mexico from LightSail 2
This image of Earth, which shows the Pacific Ocean with Baja California and Mexico on the right, was captured by LightSail 2 on 18 July 2019 at 21:45 UTC while the spacecraft was in range of its ground station at Cal Poly San Luis Obispo in California. Though LightSail 2's altitude is only 720 kilometers, its 185-degree, wide-angle camera lenses allow it to capture horizon-to-horizon Earth imagery.

Even at an altitude of 720 kilometers, the spacecraft’s boxing ring-sized solar sail creates atmospheric drag, which limits the time LightSail 2 can raise its orbit to about 1 month. As one side of its orbit raises, the other side will dip lower into the atmosphere until drag overcomes the force from solar sailing. Therefore it is essential that the spacecraft's attitude control system is functioning as expected prior to sail deployment.

Watch and The Planetary Society's Twitter, Facebook, and Instagram accounts for further updates on sail deployment.

Read more: LightSail

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Jason Davis

Editorial Director for The Planetary Society
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