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Banner image: Illustration of STPSat-6 with the Laser Communications Relay Demonstration (LCRD) payload communicating data over infrared links. Credit: NASA’s Goddard Space Flight Center

With these two different yet complementary goals, NASA also is partnering with industry to further refine laser communications hardware. In fact, LCRD includes commercially designed and built components alongside custom, NASA-developed systems. The optical module, which sends lasers to and from the payload, was designed by the Massachusetts Institute of Technology Lincoln Laboratory and built at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. However, multiple parts of LCRD came from companies like L3Harris Technologies, SEAKR Engineering, Moog Inc., and the Sierra Nevada Corporation. These include the telescope system, controller electronics system, and space switching unit – all critical to LCRD operations.

Generally, commercial efforts have been focused on developing space-to-space laser systems for use in low-Earth orbit. Companies are investing in satellite constellations which leverage laser communications to provide global broadband coverage. Proposed constellations have several hundred to thousands of satellites, creating an extensive in-space laser communications network. Commercial constellations still largely rely on radio frequency links to send data back to Earth. Whereas LCRD uses lasers for both in-space and direct-to-Earth communications.

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NASA is committed to fostering the growing space economy and the commercial aerospace community to encourage technological innovation/ bring down costs for all users. This dedication extends to new technologies and capabilities like laser communications systems.

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The U.S. Department of Defense’s Space Test Program Satellite-6 (STPSat-6), part of the Space Test Program 3 (STP-3) mission, will launch on a United Launch Alliance Atlas V 551 rocket from the Cape Canaveral Space Force Station in Florida no earlier than December 5, 2021. STP is managed by the United States Space Force’s Space Systems Command.

This being the case, when photographing objects behind glass, we can mitigate impairing reflections by mounting a polarizing filter and rotating it so that annoying reflections are rejected.

Free SpaceOptics equipment

Light reflected from non-conductive surfaces such as glass undulate mainly in one plane. When first studied, scientist falsely concluded that light waves must have a north and south pole, like a magnet. While false, the term polarized and un-polarized stuck. When light rays are reflected from the polished surface of glass windows and showcases, it will likely be polarized. Polarizing filters pass light waves that vibrate in a single plane and block light waves that vibrate in opposing planes. Consider a jump rope passed through a fence with a missing picket. The jump rope when plucked only vibrate up/down and not side-to-side.

Our televisions and computer screens display news, movies, and shows in high-definition, allowing viewers a clear and vibrant experience. Fiber optic connections send laser light densely packed with data through cables to bring these experiences to users.

NASA and commercial aerospace companies are applying similar technologies to space communications, bringing optical speeds to the final frontier. Free-space optical communications leverages recent advancements in telecommunications to allow spacecraft to send high-resolution images and videos over laser links.

While LCRD’s experimenter program will allow NASA and industry to test and refine techniques, both the agency and the commercial sector have been demonstrating and using laser communications for the past few decades.

While industry is focused on in-space optical communications to support terrestrial users, NASA is demonstrating direct-to-Earth capability from geosynchronous orbit to increase communications capabilities for future missions. With laser communications onboard, missions will be able to communicate more data in a single transmission than they could with traditional radio frequency communications.

LCRD is led by Goddard and in partnership with JPL and the MIT Lincoln Laboratory. LCRD is funded through NASA’s Technology Demonstration Missions program, part of the Space Technology Mission Directorate, and the Space Communications and Navigation (SCaN) program at NASA Headquarters in Washington, D.C.

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Katherine Schauer is a writer for the Space Communications and Navigation (SCaN) program office and covers emerging technologies, commercialization efforts, exploration activities, and more.

NASA explores the unknown in air and space, innovates for the benefit of humanity, and inspires the world through discovery.

So is it possible to get rid of these glass reflections by using polarizers? Is there a difference between regular polarizers that if what i heard is correct change the picture as you tilt the camera (just like how twisting polarized sunglasses makes the digital displays go black) and the circular polarizers when it comes to this?

How doesfree space optical communicationwork

Shown in The Mighty Circular Polarizing Filter Explained in Pictures which also explains the theory behind polarizing filters.

I wonder if the same polarizer filters we use for making the underwater look clear instead of the sky reflections blurring the water can be used for that situation.

“The Earth’s atmosphere distorts laser beams due to turbulence. Understanding these challenges are critical to enabling operational optical communications relay capability,” said Jason Mitchell, Director of the Advanced Communications and Navigation Technology division in the Space Communications and Navigation (SCaN) program at NASA Headquarters.

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Advantages offree space optical communication

Yes. Here's an example image with very similar conditions to the post you linked to. In this case they are using a circular polarizing filter:

CPL filters do not differ in their photographic properties from linear polarisers; they are merely friendlier to metering and autofocus. But in essence they are just linear polarisers with a quarterwave plane behind them that converts the passing linearly polarised light to circularly polarised light which some parts of a camera are better equipped to deal with.

Additionally, NASA’s Low-Cost Optical Terminal (LCOT) will use commercial off-the-shelf or slightly modified hardware to reduce expense and speed implementation. NASA depends on a robust domestic space industry and hopes these investments will allow the U.S. government to purchase future laser communications hardware and services. This will decrease costs while enabling more missions to use laser communications.

Polarisers can be rotated. It's worth pointing out that you can also use them for increasing the visibility of reflections by rotating them such that the polarised reflection passes through the filter completely while non-polarised light gets reduced by half in comparison.

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LCRD’s mission will be spent proving out the technology by testing laser communications capabilities with experiments from NASA, other government agencies, academia, and – in particular – the commercial aerospace community. Industry-developed experiments will allow companies to test their own technologies, software, and capabilities. NASA is providing these opportunities to grow the body of knowledge surrounding laser communications and promote its operational use.

NASA’s Laser Communications Relay Demonstration (LCRD) will send data to and from ground stations and, eventually, in-space user missions over laser links.

Light travels following a wavelike path. Water waves on a pond travel in a similar manor however, water waves undulate up/down whereas light waves freely vibrate in every possible plane. Such light wave behavior is said to be un-polarized. When light waves are reflected from some surfaces, they often become polarized. Polarized light wave vibrate however the direction of their undulation is altered.

You can suppress reflections on glass fronts pretty well if they result in polarised light. That tends to be the case completely when the reflection on the glass surface occurs at "Brewster's angle", an oblique angle. So roughly speaking you need to shoot "half sideways" at the glass reflection for best effect.

“Free-space” refers to the absence of the insulated, fiber optic cables that enable the terrestrial internet. Free-space laser communications flow freely through the vacuum of space, however atmosphere poses unique challenges to communications engineers.