Starlink: The Key To High-Speed Deep Space Communications

Imagine a world where you could video chat in real time with an astronaut on the moon, trade high-res selfies with a colonist on Mars within 15 minutes and watch a 4k video filmed that day from a NASA probe exploring deep space. SpaceX’s Starlink is the key to making these scenarios possible in the very near future.

Present Deep Space Communication Technology

Today we are living in the quintessential information age. Our modern world was made possible when the archaic dial up technologies of the 1990s gave way to high-speed connectivity. This dramatic surge in bandwidth fueled the cloud based always-on technologies that form the backbone of our modern digital lives. Current deep space communication technologies are at the same bandwidth inflection point that our terrestrial ones faced nearly 30 years ago.   For U.S. or U.S. partnership missions, the current deep space communication network relies on an aging NASA system called the “Deep Space Network.” According to NASA, the DSN is a international array of giant radio antennas that support interplanetary spacecraft missions. However, like dial up, the communication network we are relying on is becoming a bottleneck to the ever increasing data demands of modern space exploration.

The problem is really split between network capacity and the amount of data the RF spectrum can support.

First, there are only a handful of deep space networks between the space faring countries (mainly Europe, USA, China, Japan, India, and Russia) and each of those networks must be shared across all of that nation’s (or European Union partner) deep space programs. This makes time on the network a precious resource. For the U.S. space program this means that daily data from the Mars Curiosity and Perseverance Rovers are in competition for priority with data from the Voyager probes, the James Webb Space telescope, or any of the 40+ current missions it currently supports.

The U.S. has conducted over 60% of total space missions in history so for this article’s purposes, references to a deep space network through the rest of this piece refers to NASA’s deep space network.

NASA Deep Space Network

Second: The technology each of the current deep space networks uses – in general – is essentially the same radio wave transmission technology that has been in use in various forms for nearly 100 years.  While higher frequencies, data compression and other digital tweaks have increased the volume of data the network can transmit and receive, it still relies on RF transmissions to and from the surface of the Earth to the spacecraft or probe. The bottom line is that the longer wavelength of radio waves compared to other parts of the electromagnetic spectrum is ultimately the limitation of this technology.

Electromagnetic Spectrum Wavelengths

For example, if a Mars orbiter scanned the entire planet and attempted to send the data back to Earth using the current RF based network, NASA estimates it would take nine weeks to transmit.   Conversely, if the data was sent via a new optical data system using infrared lasers, which have a much shorter wave length, NASA estimates it would only take about nine days to transmit.  The difference is not the speed of the actual transmission as both RF and infrared signals travel at the speed of light, but instead the amount of data packed in that transmission enabled by the shorter wavelength of infrared light.

Waveforms: RF vs. Optical

So where does Starlink come into all of this?  A little space history to set the stage.

NASA started experimenting with Laser communication technologies in 2013 with the Lunar Laser Communications Demonstration which achieved record breaking uplink and downlink data rates between Earth and the Moon. In 2021, NASA’s Laser Communications Relay Demonstration was launched to test high-bandwidth optical communications from geostationary orbit and to demonstrate necessary relay capabilities to solve the issue of line of sight communications with Earth currently experienced by the DSN.  NASA pushed those bounds even further in 2023 with the Deep Space Optical Communications (DSOC) technology demonstration which put an infrared laser communications system on the Psyche spacecraft launched in October 2023 to visit the asteroid by the same name. 

In April 2024 things got really exciting as the Psyche spacecraft achieved a downlink of engineering data to NASA via an infrared laser at a maximum rate of 25 Mbps at a distance of approximately 140 million miles.  This distance is especially important to any future Mars missions as 140 million miles is also the average distance that Mars is from Earth making the DSOC test a fair comparison of what could be expected from an optical Earth to Mars communication link.  Even more promising for upcoming moon missions is that the data rate increased significantly the closer the transmitter was to Earth.  In December 2023 Psyche transmitted an ultra-high-definition video to earth at a distance of 19 million miles and achieved a downlink speed of 267 Mbps. This speed is on par with terrestrial broadband internet systems at a distance of nearly 80 times further than the Moon is from the Earth.

NASA Psyche spacecraft Deep Space Optical Data Transmission

The Future: Enter Starlink. 

While NASA was testing infrared laser communications on experimental systems, SpaceX began launching lasers into space by the thousands.  Starlink first launched into space in May 2019 but by 2021 SpaceX had upgraded the design to include optical space lasers on each satellite launched in 2022. In the current design, each Optical Space Laser is capable of transmitting up to 200 Gbps enabling SpaceX to build a mesh network in space.  This allowed the company to use its thousands of satellites to link areas on the ground that had no nearby base stations and still provide high speed data connections.

SpaceX wont formally acknowledge what kind of laser they are using, but a few enterprising Reddit commentors managed to find the laser wavelengths buried in the Dishy firmware. Based on the Dishy Firmware system configurations Starlink uses lasers on both the 1556 nm and 1549 nm wavelengths. This places it in the near infrared spectrum and at similar wavelengths as the DSOC system operating on the Psyche spacecraft.

According to SpaceX engineer Travis Brashears, as of January 2024, Starlink now has 9000 lasers in orbit which are routinely transmitting 42 million gigabytes of data per day.  The current system is so robust that it has achieved a achieved a laser “link uptime” at over 99% despite the mesh network forming 266,141 “laser acquisitions” per day.

SpaceX Starlink Laser Mesh Network Presentation

The current Deep Space Network is both constrained by limited link points and by the bandwidth constraints of the radio frequency portion of the EM spectrum it operates on.  The bandwidth side of this equation is obviously answered by shifting to an optical network.  NASA has proven that an infrared laser communication system allows for a 10x to 100x increase in data transmission ability which solves the bandwidth side of the bottleneck. However, NASA currently has only a handful of experimental optical communication systems in use which does not resolve the link side of the bottleneck.

SpaceX’s stated reason for building Starlink is to provide “high-speed, low-latency internet to users all over the world.”  This goal publicly only acknowledges Earth based communication, but as we have written before, all of Elon Musk’s companies serve some purpose towards his stated Mars exploration and colonization ambitions.  In this case, Starlink answers both the link and the bandwidth sides of the problem simultaneously and lays the foundations for Earth, Mars and deep space communications.   SpaceX has used their Earth based Starlink service to test their optical space laser technology and prove it can maintain an active mesh network that increases reliability and provides thousands of potential link points.

Bringing the entire concept full circle

Starlink is the solution to the current deep space network bottleneck and even in its current form is the ultimate mesh network connecting nodes across hundreds of miles of space. No matter if it is in your house or orbiting a planet, a mesh network is just collection of independent nodes that function as a singular network. Starlink has the potential to tie in nodes around the Earth, the Moon, Mars or even Starships enroute to Mars into this expansive mesh network allowing them to take advantage of the Starlink infrastructure.  This solves the communication bottlenecks while at the same time creating a nearly seamless transition from a terrestrial network to one that allows us to reach to the stars, and phone home when we need to.