Starlink’s Inter-Satellite Laser Links Are Setting New Record With 42 Million GB Per Day

February 5, 2024 by Maya Posch 44 Comments

Slide from the SpaceX Starlink presentation on mesh routing via the laser links. (Credit: PCMag/Michael Kan)

Although laser communication in space is far from novel, its wide-scale deployment as seen with SpaceX’s Starlink satellite internet constellation has brought the technology to the forefront like never before. This was quite apparent during the SPIE Photonics West event on January 30th when [Michael Kan] and other journalists attended a presentation by SpaceX’s [Travis Brashears] on the inter-satellite laser communication performance that was first enabled with the Starlink v1.5 satellites.

Among currently active inter-satellite communication systems, Starlink is by far the most numerous and with the highest bandwidth, reaching over 42 PB per day across its over 9000 space lasers (yes, that is over 9000) for a 5.6 Tbps throughput. Since these satellites form a mesh network with their 100 Gbps laser transceivers, a big part of using it efficiently is to route any data with the least amount of latency while taking into account link distance (maximum of 5,400 km), link duration (up to multiple weeks) and presence of other Starlink satellites before they become within reach. With this complex mesh in LEO, this also means that a very high uptime can be accomplished, with a claimed 99.99% due to rapid route changing.

For the future, SpaceX has plans to not only keep upgrading its own Starlink satellites with better laser transceivers, but to also make them available to third-party satellites, as well as beam the lasers directly down to Earth for ground-based transceivers. The latter is still cutting edge, despite it being tested to beam cat videos to Earth from Deep Space.

NASA’s Tech Demo Streams First Video From Deep Space Via Laser

December 19, 2023 by Maya Posch 46 Comments

Everyone knows that the most important part of a tech demo is to make the right impression, and the team over at NASA’s Jet Propulsion Laboratory (JPL) definitely had this part nailed down when they showed off streaming a cat video from deep space using laser technology as part of NASA’s Deep Space Optical Communication (DSOC) program. This system consists out of a ground-based laser transmitter and receiver along with a space-based laser transceiver, which for this experiment was positioned at a distance of 31 million kilometers – 80 times the distance between the Moon and Earth – as a part of the Psyche spacecraft.

After a range of tests with the system to shake out potential issues, the team found that they could establish a 267 Mbps link, with a one-way latency of a mere 101 seconds, allowing Psyche’s transceiver to transmit the preinstalled 15-second high-definition video in effectively real-time and making the cat Taters instantly world-famous. Although the potential for space-based cat videos cannot be underestimated, the main purpose of DSOC is to allow spacecraft to send back much larger data sets than they could before.

For robotic and potential future manned missions DSOC would mean high bandwidth video and data links, enabling more science, better communication and possibly the occasional cat video during interplanetary travel.

Continue reading “NASA’s Tech Demo Streams First Video From Deep Space Via Laser” →

Artemis II Will Phone Home From The Moon Using Laser Beams

May 14, 2023 by Joseph Long 52 Comments

[NASA] Astronauts will be testing the Orion Artemis II Optical Communications System (O2O) to transmit live, 4K ultra-high-definition video back to Earth from the Moon. The system will also support communication of images, voice, control channels, and enhanced science data.

Aboard Orion, the space terminal includes an optical module, a modem, and a control system. The optical module features a four inch telescope on a dual gimbal mount. The modem modulates digital information onto laser beams for transmission back to Earth, and demodulates data from laser beams recieved from Earth. The control system interfaces with avionic systems aboard Orin to control and point the communications telescope.

On Earth, facilities including the Jet Propulsion Laboratory and the White Sands Complex will maintain high-bandwidth optical communication links with Orion. Information received from Orion will be relayed to mission operations, scientists, and researchers.

NASA’s Laser Communications Relay Demonstration (LCRD) showcases the benefits of optical communications. Traditionally, missions relied upon radio communication, but improved technology will better serve space missions that generate and collect ever-increasing quantities of data. Optical communication solutions can provide 10 to 100 times the bandwidth of radio frequency systems. Other improvements may include increased link distances, higher efficiency, reduced interference, improved security, and reductions in size and weight. Our Brief History of Optical Communication outlines many of these advantages.

Continue reading “Artemis II Will Phone Home From The Moon Using Laser Beams” →

A Brief History Of Optical Communication

February 18, 2021 by Moritz v. Sivers 44 Comments

We live in the information age where access to the internet is considered a fundamental human right. Exercising this right does largely rely on the technological advances made in optical communication. Using light to send information has a long history: from ancient Greece, through Claude Chappe’s semaphore towers and Alexander Graham Bell’s photophone, to fiber optic networks and future satellite internet constellations currently developed by tech giants.

Let’s dive a little bit deeper into the technologies that were used to spread information with the help of light throughout history. Continue reading “A Brief History Of Optical Communication” →