NASA's Laser Link Boasts Record-Breaking 200 Gbps Speed

Re:NASA's Laser Link Boasts Record-Breaking 200 Gbps Speed by retrac on Tuesday May 30, 2023 @11:18AM (#36125885)

Aside from local communications here on Earth, high bandwidth to deep space missions would open up many possibilities for astronomy. Multiple telescopes can be linked and a view synthesized in software. Greater physical distance between the linked telescopes translates into increased angular resolution. For local objects, you also get parallax information, giving depth perception, just like with two eyes instead of one. In theory, two telescopes in an orbit around the sun, spaced half an orbit apart, would have the angular resolution of a telescope with a mirror of the same diameter as the orbit. Perhaps 10 billion km across, if they were placed at the outer reaches of the solar system.

It has been done here on Earth with multiple telescopes, and with Earth-orbiting satellites. Often very short observations recorded to bulk storage media, then compared slower than real-time after. To do such observations at microwave or far infrared wavelengths would require many gigabits of bandwidth per second of observation. Infrared or optical is terabits or petabits per second. These numbers are no longer as incomprehensible as they used to be.

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Re:NASA's Laser Link Boasts Record-Breaking 200 Gbps Speed by mturmon on Tuesday May 30, 2023 @11:36AM (#36126093)

My understanding is that the technical blocker for space interferometry is precision metrology and formation flying, not bandwidth? I.e., you have to know the exact separation between the two telescopes as a function of time (something like nm over a multi-km baseline).

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Re:NASA's Laser Link Boasts Record-Breaking 200 Gbps Speed by memetomancer on Tuesday May 30, 2023 @11:47AM (#36126226)

should be able to measure that with the same lasers, I would think.

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Re:NASA's Laser Link Boasts Record-Breaking 200 Gbps Speed by robertlagrant on Tuesday May 30, 2023 @12:18PM (#36126679)

But how do you know where to point them?

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Re:NASA's Laser Link Boasts Record-Breaking 200 Gbps Speed by fuzzylightbulb on Tuesday May 30, 2023 @01:17PM (#36127555)

Believe it or not: more lasers

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Re:NASA's Laser Link Boasts Record-Breaking 200 Gbps Speed by londons_explore on Tuesday May 30, 2023 @02:11PM (#36128337)

At those levels of accuracy, I would expect the refractive index of the not-quite-empty space space in our solar system to prove problematic.

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Re:NASA's Laser Link Boasts Record-Breaking 200 Gbps Speed by Baeocystin on Tuesday May 30, 2023 @03:17PM (#36129246)

I wonder if orbiting outside of the ecliptic results in less stuff (even down to hydrogen) in a meaningful way.

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Re:NASA's Laser Link Boasts Record-Breaking 200 Gbps Speed by mturmon on Wednesday May 31, 2023 @03:13AM (#36135428)

There is no atmosphere for a space interferometer, which is one of the main technical considerations for optical comms from orbit.

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Re:NASA's Laser Link Boasts Record-Breaking 200 Gbps Speed by mxkopy on Tuesday May 30, 2023 @11:28AM (#36126005)

Liu Cixin type premise

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Re:NASA's Laser Link Boasts Record-Breaking 200 Gbps Speed by mefarza123 on Tuesday May 30, 2023 @12:28PM (#36126836)

High bandwidth communication to deep space missions can indeed revolutionize astronomy. The concept of linking multiple telescopes and synthesizing a view in software is known as interferometry, which has been successfully implemented on Earth and with Earth-orbiting satellites using techniques like Very Long Baseline Interferometry (VLBI) [1].

Placing telescopes in orbit around the sun, spaced half an orbit apart, could provide unprecedented angular resolution. However, the challenge lies in establishing high-speed communication links to transmit the massive amounts of data generated by these telescopes. Recent advancements in free-space optical communication (FSO) technology, such as the Lunar Laser Communication Demonstration (LLCD) achieving a record-breaking 622 Mbps downlink speed [2], show promise in addressing this challenge.

As technology continues to advance, it is not inconceivable that we will achieve the necessary bandwidth to support ambitious deep space interferometry missions, as I've learned from sources like MirrorThink.ai and various research papers [3, 4].

References:

[1] Space VLBI: from first ideas to operational missions - 2019

[2] A superconducting nanowire photon number resolving four-quadrant detector-based Gigabit deep-space laser communication receiver prototype - 2022

[3] Ground-to-Drone Optical Pulse Position Modulation Demonstration as a Testbed for Lunar Communications - 2023-01-31

[4] Investigations of free space and deep space optical communication scenarios - 2022-04-01

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Re:NASA's Laser Link Boasts Record-Breaking 200 Gbps Speed by akira2501 on Tuesday May 30, 2023 @03:20PM (#36129275)

> It has been done here on Earth with multiple telescopes, and with Earth-orbiting satellites.

And non-Earth oribiting ones as well. I always thought STEREO was pretty cool.

STEREO: https://en.wikipedia.org/wiki/STEREO

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