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As everybody knows, the pioneering work of The Professor and his serendipitous collaborator Gilligan demonstrated the reality of ground to space optical communications back in 1964. In that case information was encoded in the incandescent radtaion of soot particles via spatial modulation1 rather than the more modern temporal modulation.

The launch of this crewed and remarkable mission can be seen here.

Questinon: Since that "fateful trip", how many independent demonstrations of optical communications between ground and space have been successful?


1 https://www.imdb.com/title/tt0588095/mediaviewer/rm2807151617

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+100
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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 использована для эксперимента по исследованию возможности передачи информации методом время-импульсной модуляции по оптическому каналу связи Алма-Ата - "Луноход-2". Объект использовался для ретрансляции сигналов на Землю по радиоканалу. Пропускная способность данной линии связи равна 15 дв.зн/сек."

The same ground-based equipment was used for an experiment to study the possibility of transmitting information by the method of time-pulse modulation over the optical communication channel Alma-Ata - Lunokhod-2. The object was used to relay signals to Earth via a radio channel. The throughput of this communication line is 15 two-digit characters per second. http://russianspacesystems.ru/wp-content/uploads/2018/01/1973_Radiotekhnicheskiy_kompleks_Luna21_Lunokhod_2.pdf

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  • $\begingroup$ Thanks, this is absolutely awesome!!! $\endgroup$
    – uhoh
    Nov 17 '20 at 18:14
  • 2
    $\begingroup$ "дв.зн." probably means "двоичных знаков", "binary digits" (i.e., bits). $\endgroup$
    – Litho
    Mar 3 at 19:30
  • $\begingroup$ I'm still hoping for a complete answer but this is so important (and since it's expiring) I'll award the bounty here. Thanks! $\endgroup$
    – uhoh
    Mar 10 at 6:12
  • $\begingroup$ But Lunokhod-2 was only used for laser ranging. All it had onboard were retro-reflectors, which reflected light sent from Earth. You're talking about a ground-based experiment but I cannot find any translatable reference to laser communication with respect to this mission. $\endgroup$
    – Polar_Bear
    Nov 7 at 20:11
  • $\begingroup$ @Polar_Bear page 62 "Прибор ФА010" $\endgroup$
    – A. Rumlin
    Nov 9 at 5:53
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+200
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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 missions, achieved as well as planned. Source: Development Current Status and Trend Analysis of Satellite Laser Communication

State/ organization Terminal name Launch time Major institutions Communication distance Communication wavelength Communication rate
USA GOLD 1995 NASA JPL GEO→GND 830 nm(downlink) 1.024 Mbps@PPM(downlink)
USA GOLD 1995 NASA JPL GEO→GND 514.5 nm(uplink) 1.024 Mbps(uplink)
USA GeoLITE 2001 MIT LL GEO→GND / /
USA LRO 2013 NASA GSFC Lunar→GND 1064.3 nm(downlink) 300 bps@PPM(downlink)
USA LLCD 2013 NASA GSFC Lunar→GND 1550 nm(downlink)1558 nm(uplink) 622 Mbps@PPM(downlink)
USA LLCD 2013 NASA GSFC Lunar→GND 1550 nm(downlink)1558 nm(uplink) 20 Mbps@PPM(uplink)
USA OPALS 2014 NASA JPL ISS→GND 1550 nm(downlink) 30~50 Mbps@IM/DD(downlink)
USA OCSD-B 2018 NASA LEO→GND 1064 nm(downlink) 50 Mbps/100Mbps@IM/DD(downlink)
USA LCRD 2021 NASA GSFC GEO→GND 1550 nm(duplex) 2.88 Gbps@DPSK(duplex)
USA LCRD 2021 NASA GSFC GEO→GND 1550 nm(duplex) 622 Mbps@PPM(duplex)
USA ILLUMA-T 2022 NASA GSFC LEO→GEO 1550 nm(duplex) 1.244 Gbps@DPSK(return link)
USA ILLUMA-T 2022 NASA GSFC LEO→GEO 1550 nm(duplex) 51 Mbps(forward link)
USA TBIRD 2022 NASA MIT LEO→GND 1550 nm(downlink) 200 Gbps(downlink)
USA TBIRD 2022 NASA MIT LEO→GND 1550 nm(downlink) 5 kbps@PPM(uplink)
USA O2O 2023 NASA JPL Lunar→GND 1550 nm(downlink) 80 Mbps@PPM(downlink)
USA O2O 2023 NASA JPL Lunar→GND 1550 nm(downlink) 20 Mbps(uplink)
USA DSOC 2022 NASA JPL Mars→GND 1550 nm(downlink)1060 nm(uplink) 264 Mbps@PPM(downlink)
USA DSOC 2022 NASA JPL Mars→GND 1550 nm(downlink)1060 nm(uplink) 2 kbps(uplink)
USA LOCNESS 2025 NASA GSFC GEO→GEO / 100 Gbps(GEO→GEO/GND)
USA LOCNESS 2025 NASA GSFC GEO→GND / 10 Gbps(GEO→LEO)
USA LOCNESS 2025 NASA GSFC GEO→LEO /
Europe SILEX 2001 ESA LEO→GEO 847 nm(LEO) 50 Mbps@IM/DD(LEO)
Europe SILEX 2001 ESA GEO→GND 819 nm(GEO) 2 Mbps@PPM(GEO)
Europe TerraSAR→X 2008 DLR LEO→LEO 1064 nm(duplex) 5.6 Gbps@BPSK(duplex)
Europe EDRS-A 2016 ESA GEO→GEO 1064 nm(duplex) 1.8 Gbps@BPSK(duplex)
Europe EDRS-A 2016 ESA GEO→LEO 1064 nm(duplex) 1.8 Gbps@BPSK(duplex)
Europe EDRS-C 2019 ESA GEO→GEO 1064 nm(duplex) 1.8 Gbps@BPSK(duplex)
Europe OPTEL-μ 2018 RUAG LEO→GND 1550 nm 2.5 Gbps@IM/DD(downlink)
Europe OSIRISv3/4 2020 DLR LEO→GND 1500 nm 10 Gbps@IM/DD(downlink)
Europe EDRS-D 2025 ESA GEO→GEO 1064 nm/1550 nm(duplex) 3.6 Gbps~10Gbps@BPSK(duplex)
Europe HydRON 2025 ESA GEO→LEO 1064 nm/1550 nm 100 Gbps
Europe HydRON 2025 ESA GEO→GND 1064 nm/1550 nm 100 Gbps
Japan ETS-VI 1994 NICT GEO→GND 830 nm(downlink) 1.024 Mbps@PPM(downlink)
Japan ETS-VI 1994 NICT GEO→GND 514.5 nm(uplink) 1.024Mbps(uplink)
Japan OICETS 2006 JAXA/NICT LEO→GND 847 nm(downlink) 49.3724 Mbps@NRZ(downlink)
Japan OICETS 2006 JAXA/NICT LEO→GND 815 nm(uplink) 2.048 Mbps@PPM(uplink)
Japan SOTA 2014 NICT LEO→ GND 980/1550 nm(downlink) 1 Mbps~10 Mbps@OOK(downlink)
Japan VSOTA 2019 NICT LEO→GND 980/1550 nm(downlink) 1 kbps~1 Mbps@OOK/PPM(downlink)
Japan JDRS 2020 JAXA/ NICT GEO→LEO 1540 nm(return link) 1.8 Gbps@RZ→DPSK (return link)
Japan JDRS 2020 JAXA/ NICT GEO→LEO 1560 nm(forward link) 50 Mbps@IM/DD(forward link)
Japan HICALI 2021 NICT GEO→GND 1500 nm(downlink) 10 Gbps@DPSK(downlink)
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  • $\begingroup$ Wow! That's a lot more than I expected. Thanks! $\endgroup$
    – uhoh
    Nov 7 at 21:50
0
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Laser communication in space is the use of free-space optical communication in outer space. Communication may be fully in space (an inter-satellite laser link) or in a ground-to-satellite or satellite-to-ground application.

The main advantage of using laser communication over radio waves is increased bandwidth, enabling the transfer of more data in less time.

In November 2014, the first-ever use of gigabit laser-based communication as part of the European Data Relay System (EDRS) was carried out. Further system and operational service demonstrations were carried out in 2014. Data from the EU Sentinel-1A satellite in LEO was transmitted via an optical link to the ESA-Inmarsat Alphasat in GEO and then relayed to a ground station using a conventional Ka-band downlink. The new system can offer speeds up to 7.2 Gbit/s.The Laser terminal on Alphasat is called TDP-1 and is still regularly used for tests. The first EDRS terminal (EDRS-A) for productive use has been launched as a payload on the Eutelsat EB9B spacecraft and became active in December 2016. It routinely downloads high-volume data from the Sentinel 1A/B and Sentinel 2A/B spacecraft to the ground.

So far (April 2019) more than 20000 links (11 PBit) have been performed.

This Wikipedia gives more answers: Laser Communication in Space

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  • $\begingroup$ Thank you for your answer! It is true that for spacecraft in low Earth orbit radio is limited in bandwidth compared to optical. But there are other advantages to using optical for LEO besides bandwidth. With a wavelength roughly 10,000 times smaller, the "antennas" are now small telescopes of 5 to 50 cim in diameter rather than meter to tens of meters, and fast pointing and tracking is a lot easier because they are both compact and well, they are telescopes and so can more easily track signals by imaging the transmitted spot and in some cases other things as well. $\endgroup$
    – uhoh
    Mar 6 at 15:00
  • $\begingroup$ But for deep space applications, let's say to Mars or Jupiter or even the Kuiper belt, bandwidths are far lower than radio is capable, and that's because the wavelengths are centimeters. Antenna gains on the ground are 40 or 50 dB only, and those big dishes on spacecraft are 10 to 20 dB. Where optical communications really "shines* (pardon the pun) is for deep space. A 30 cm telescope will have a gain of 120 dB, but one at each end and you will have a much stronger signal. This is not because the bandwidth per se is bigger, but because the signal is larger than thermal noise over wider freq. $\endgroup$
    – uhoh
    Mar 6 at 15:05
  • $\begingroup$ Also, the question asks "How many independent demonstrations...?" not how many "links". To answer you'll need to count the number of independent demonstrations that were successful. I think that the answer is a half-dozen or less, not "20,000". $\endgroup$
    – uhoh
    Mar 6 at 15:06
  • $\begingroup$ Here's an example of a link budget calculation where those gains can be used to calculate a data rate: space.stackexchange.com/a/50575/12102 $\endgroup$
    – uhoh
    Mar 6 at 15:12

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