# Tag Info

Accepted

### Do the latest Starlink satellites use inter-satellite laser communications?

All I could find was here which led to a variety of articles which explain the technology in depth. Not that Wikipedia is always reliable, however it stated that: The satellites will employ optical ...
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### Data rate in optical free space communication systems

You need to look carefully at how it's measured. One of the major contributors to data rate is availability: with low Earth orbit satellites they might only have a few minutes of downlink opportunity ...
• 410

### Would plasma sheathes from reentry heating block optical/UV communications as well as radio?

The problem is the plasma is VERY bright. I can't find all the numbers easily but let's find a ballpark figure cobbling some available data together. A reentry capsule of $m=3$ tons (like Soyuz). ...
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### Would plasma sheathes from reentry heating block optical/UV communications as well as radio?

As it happens, reentry temperatures peak at approximately the same temperature in kelvins as reentry speed in m/s, so assuming roughly 8 km/s, 8000 K is the figure to work from. This diagram from ...
• 4,526
Accepted

### How is long-distance optical communications coming along in space?

The European Data Relay System has recently begun testing. It's for getting data from Earth orbiting satellites down to the ground quickly, without waiting for the satellite to pass over a base ...
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### There are only a few suppliers of optical terminals: what is the reason?

Challenges Mass production and industrialization: The industry has geared up over decades to supply radio equipment such as phased-array antennas and hardware on satellites. Shifting the production ...
• 410

### How is long-distance optical communications coming along in space?

The lunar mission which tested optical communication was LADEE. The ISS program you're thinking of is OPALS. Both tests succeeded, but neither was meant for ongoing operation. LADEE intentionally ...
• 301
Accepted

### Did Perseverance get an experimental optical communications terminal?

It looks like the answer is probably no. The paper from the 2015 talk seems to refer to this as "a recent NASA JPL study", and notes that it would need a similar terminal on an orbiter. It ...
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Accepted

### How did LADEE and LDRC measure it's distance from Lunar orbit to Earth to 1 centimeter accuracy using optical communications?

In case of optical communication we don't deal with electromagnetic waves that are collected in an antenna at a ridiculously low power level, are amplified by many orders of magnitude and then need to ...
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### Frequency/Spectrum regulation document for laser communication

Laser communication is not regulated by the International Telecommunication Union or Federal Communications Commission and it can be used without restrictions and does not require costly licenses. ...
• 115

### How many independent demonstrations of optical communications between ground and space have been successful?

Quite a few. Indeed the first ever use of lasercom space-to-ground was in 1994. This was achieved by Japan’s 1-Mb/s laser link to ground from the ETS-VI satellite in GEO. Here are some state-sponsored ...
• 410

### How many independent demonstrations of optical communications between ground and space have been successful?

Probably the first and only ground to space optical communications experiment with an object on the lunar surface was a laser communication line with Lunokhod-2. "Эта же наземная аппаратура была ...
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### Have amateur satellites ever experimented with optical communications?

Not really amateur, but CubeSats for sure. AeroCube 7 / OCSD would have already tested it, but had attitude control problems. Should relaunch in a few months. One can find plenty of detailed ...
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Accepted

### Have amateur satellites ever experimented with optical communications?

There was one that I can find, a beacon that used infrared light to communicate at a rate or 400 bits/second, on AO-40, which was a technology demonstration mission by AMSAT. ...
• 119k
Accepted

### Characteristics of the inter-satellite optical link

Yes, the optical link being discussed is a laser--here's an article (behind a paywall, but the abstract mentions that the technology is laser technology) that discusses the exact satellite link you're ...
• 539

### How to compute each of these link budget terms?

First, a general warning. There is widespread agreement on the full link budget equation, but there are many ways to group its components into named pieces, and different authors make different ...
• 6,012
Accepted

### What GEO relay satellite will the ISS use for end-to-end optical communication with a ground station?

ILLUMA-T will work with the LCRD flight segment payload on Space Test Program Satellite-6 (STPSat-6); see page 4 of this document from SCAN. LCRD’s dual optical link system will allow it to serve ...
• 12.4k

### Characteristics of the inter-satellite optical link

A bit of sparse data are available for the EDRS system from ESA: EDRS And a bit from Airbus EDRS At least some basic data rates and distances.
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### Would plasma sheathes from reentry heating block optical/UV communications as well as radio?

The re-entry blackout problem was resolved for the Space Shuttle with the implementation of the TDRSS system. It consists of (currently) 7 satellites in geostationary orbit. During re-entry, the ...
• 345

### Are there plans or a program for an optical relay pathfinder for deep space?

What's on the flatbed trailer? If you're referring to slide 4, that's a FRAM (Flight Releasable Attachment Mechanism) - it's a standardized roughly 4x4 foot pallet like thing that the SCaN Testbed is ...
• 21
Accepted

### Are there plans or a program for an optical relay pathfinder for deep space?

Unfortunately, those slides don't provide much information on what they mean by "relay pathfinder" but the concept of using optical communication in space has been tested and is planned for ...
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### PAT (Pointing Acquisition, and Tracking) system in lasercom

You said that the main challenges are: PAT Operating environment Yes they are solved problems. But please elaborate: Who said these are the main challenges? In the links you gave, someone mentioned ...
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### Beacon (PAT) in optical free space communication

The beacon doesn't need to be purposefully widened. It is very narrow compared with radio and microwaves, but it will always diverge a little bit due to physics, such that it covers a fairly big area ...
• 410

### Optic communication: day and night

Partial answer: To some extent optical links can be almost completely immune to sunlight! Temporal The signals are modulated on a "carrier frequency" the baseline rate at which the laser is ...
• 148k
Accepted

### Do we use masers, lasers or infrared lasers to send data from deep space back to Earth? If not, why not?

"Why don't current missions already use small masers..." So we have already been using conventional traveling wave tube amplifiers for microwave communications in space. Ka band is around 30 ...
• 148k
1 vote

### What are the reasons for the specific operating wavelengths chosen for laser communication?

As mentioned, in the other answer, cost and availability for 780 and 1064 are important. At the systems level, You also may want to use a cheaper silicon imagining detector to detect your beacon. ...
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1 vote

### What are the reasons for the specific operating wavelengths chosen for laser communication?

Beacon wavelength window is 780 to 1064 nm, for data transmission is 1520– 1560 (1600) nm. Could someone explain why beacon signal operates in lower range? I don't have the book handy, but I can ...
• 148k
1 vote

### Receiver and transmitter in RF/optic satellite communication: distance vs data rate v2

This is interesting! At first I thought that optical communication always wins because the $\lambda/d$ for a 30 cm diameter telescope at 850 nm is about 350,000 whereas for a 3 meter dish on a deep ...
• 148k
1 vote
Accepted

### "...extending the Starlink network using longer-range laser comms and relay satellites to reach Mars and Starships in-transit" (Musk & Shotwell)

They haven't publicly laid out detailed plans, but they have or are actively working on all the pieces such a system would require, and have mentioned it a couple times. Shotwell discussed it in an ...
1 vote
Accepted

### Will future deep space optical communications "ground stations" actually be in space, or on the ground?

One report of a study on the topic funded by NASA JPL in 2005 is "Deep-space to ground laser communications in a cloudy world". Based on global cloud statistics, they worked out the ...
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