LightSail 2 has successfully used its awnings. Shortly after 12:00 PST, the Planetary Society tweeted that the sails were set and the spacecraft sailed with sunlight. We can all enjoy their success and wonder how awnings will fit in with humanity's plans for space exploration.
This is a dramatic moment for LightSail 2 and The Planetary Society, the world's largest charitable space organization. LightSail 2 is the third spacecraft in their LightSail program. It was launched on June 25 and has been in orbit ever since, preparing for the sailing mission and sending us some cute pictures of the earth.
A series of tweets from The Planetary Society told the story all morning.
The sail of LightSail 2 is actually a system of four smaller triangular sails that form a large square when deployed. After exposure, the sail measures 32 square meters. After exposure, it can be used to raise the spacecraft's orbit and demonstrate the power and utility of awnings.
Next came a telemetry of the tiny satellite The number of engines soared. Telemetry also showed that the cameras were active.
We are still waiting for some new pictures of LightSail 2, but we have this nice GIF that we can watch in the meantime.
If you are unfamiliar with awning technology, the idea is, at least theoretically, relatively simple.
An awning uses the momentum of photons coming from the sun, much like a sailboat captures the energy in the wind. The light sail does not catch the photons. The photons bounce off the reflective surface and drive the sail. It's a lightweight, simple technology with great potential.
In the vacuum of the room it works. There is no resistance to the momentum of the spacecraft, so over time more and more photons bounce off it and its speed increases. Everything without fuel or other drives.
In a sense, the awning is just like a sail on a boat. The sail may be angled to direct the spacecraft's journey. When the sails are aimed directly at the sun, the spaceship moves directly away from the sun. However, a spaceship that uses awning or changes the sail angle can steer and travel through the solar system and beyond.