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How LightSail Holds Its Place in Space

Posted by Jason Davis

20-02-2015 4:00 CST

Topics: LightSail

There are few systems aboard a spacecraft more important than attitude control. Most things in space need the ability to point toward other things in space. The Hubble Space Telescope locks on to distant celestial objects. Earth-observing satellites focus on our planet. And a Soyuz capsule lines itself up with the International Space Station before pulling in to a docking port.

For CubeSats, it's no different. And while some of these tiny spacecraft tumble aimelessly around the Earth, others hold their positions using momentum wheels and electromagnetic torque rods. For our full-fledged solar sail flight in 2016, we'll tack LightSail like a sailboat on a lake, alternately turning parallel and perpendicular to the ceaselss stream of solar photons.

Our first LightSail spacecraft, which will ride an Atlas V rocket to orbit this May, won't fly high enough to solar sail. But we still need a way to hold a stable position in orbit. We do this using torque rods that interact with Earth's magnetic field. This also gives us a way to predict LightSail's orientation at any given point.

If that sounds confusing or jargon-laced, the following infographic is for you. Click the image below to head over to our new LightSail website, and see how the spacecraft's attitude control system holds its place in space.

See other posts from February 2015


Or read more blog entries about: LightSail


spacefanatic: 02/21/2015 02:02 CST

Great explanation, Jason. The science behind LightSail's attitude control system is absolutely awesome.

Chronicle: 02/21/2015 11:01 CST

At first I thought there was a grammatical error: "The science behind LightSail's attitude control system is absolutely awesome." I thought it was supposed to read "altitude". :) Further reading clarified the post. I am a new member and think what you are doing is wonderful! - Jimmy Chronicle

Paul F: 02/23/2015 10:56 CST

Hmmm. When I sat in on the Lightsail-1 Preliminary Design Review, I pointed out that it might be hard to get a UHF signal in or out of the spacecraft due to interfering RF bouncing off the grounded, metallized sail. The answer was that the antenna would be pointed at the Earth and would reject the reflected energy from the side-lobes. However, this shows a 60 degree angle from the ground coming into the antenna and almost the same angle when reflecting off the sail - so the main and reflected signals are going to be almost coincident. You might have very narrow windows where you can get clean telemetry out and commands in and might want to prepare for that operationally, if you have not already done so. Anyway, best of luck with this cool spacecraft.

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