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Drama in near-Earth orbit while LightSail2 sets sail



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.

  The removed light sail measures 32 square meters or 340 square feet. Picture credits: The Planetary Society.
The used light sail measures 32 square meters. Picture credits: The Planetary Society.

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.

Awning Technology

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.

<img src = "https://www.universetoday.com/wp-content/uploads/2019/07/900px-IKAROS_solar_sail.jpg" alt = "An artistic depiction of the Japanese spaceship IKAROS, the first spacecraft, the Picture credits: By Andrzej Mirecki – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=14656159[19659017<ArtisticrepresentationofJapaneseRoomprobeIKAROSdemonstrictingthefirstinterfaceofSolarsegelTechnologyPicture:ByAndrzejMirecki-ParentsOfficeCCBY-SA30https://commonswikimediaorg/w/indexphp?Curid=14656159[19659018lightboxesYou'regettingmoreandmoreonthewayyoucanalsoacceleratephotonwalkingonaSunSailspaceshipcanreachachemicalmissilethatcan'tobviouslyreachalltheattractionsofEarth

Of course, momentum can not increase forever with the same speed iter an awning is removed from the sun, the fewer photons hit it. And although it does not slow down the emptiness of space, its rate of acceleration drops.

For all these reasons, awnings are designed for long distances, where a simple but effective propulsion system can shine. There is even the idea that lasers could be aimed at sun shades to make them even faster.

Laser Awnings

The Breakthrough Starshot project aims to send a fleet of small awning spaceships to our nearest star neighbor, Alpha Centauri. Rather than relying on the sun's energy alone to get there, it would be powered by a series of lasers whose photons would hit the sails just like the sun's. The laser array accelerated the spacecraft to a speed of about 60,000 km / s (37,282 mps) – or 20% of the speed of light.

This image shows the star system closest to the sun, the bright double star Alpha Centauri AB and its distant and weak companion Proxima Centauri. At the end of 2016, ESO signed an agreement with the Breakthrough Initiatives to adapt the VLT instrumentation to search for planets in the Alpha Centauri system. Such planets could be the target of a possible launch of miniature space probes by the Breakthrough Starshot Initiative. Credit: ESO

Alpha Centauri is 4.37 light-years away, and even with the lasers, the Breakthrough Starshot project would take another 20 years.

But this is a very different and more ambitious project than LightSail 2. The Breakthrough Starshot is the project of a Russian billionaire, while LightSail is a public, nonprofit spacecraft built with funds from enthusiastic supporters.

And his success today is a nice achievement.

LightSail 2 is a demonstration mission to show how even a small awning can lift the orbit of a spacecraft. There are still many obstacles to overcome in order to enlarge it. There may be commercial applications for small satellites, and eventually its technology may play a role in exploring our solar system.

But for today, enjoy the success of the Planetary Society!

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