Intersatellite optical links, or laser crosslinks, are poised to transform space communication by improving data transmissions speed and reliability. While widespread use of laser crosslinks direct data transmission between satellites could reduce reliance on ground stations, there’s no getting around the ground for the data that needs to get down. Ground network architectures will change, not go away.
“When I put on my technical hat, the idea that a lot of data will come down in certain regions because you’ll have intersatellite links makes sense,” said Brad Bode, Atlas Space Operations chief technology officer and chief information officer. “However, the business side of me asks how long this is going to take?”
BUSINESS IS BOOMING
For the moment, the satellite ground segment sector is booming as more and more satellites enter service. In 2022, a record 180 orbital launches worldwide lofted nearly 2,500 payloads, up from 1,829 in 2021, according to data compiled by astrophysicist and spaceflight analyst Jonathan McDowell.
To keep up with growing demand for satellite command and control, and data downlink services, companies are installing radio frequency antennas at new and existing sites, and forging alliances.
RBC Signals reported record revenues in 2022. Annual earnings are climbing by double digits for Italy’s Leaf Space. And Norway’s Kongsberg Satellite Services continues expanding its 280-antenna network.
“Satellites communicating with each other through intersatellite links is all well and good if that data is needed in space,” said Christopher Richins, RBC Signals co-founder and CEO. “But as long as decisions are being made on the ground or information is being required on the ground, ground stations will be needed.”
Is it possible that in the future companies might need fewer ground stations because so much data is transferred through optical intersatellite links? Yes.
“Data relay systems of any kind should reduce the need for site diversity, eventually,” says Caleb Henry, Quilty Analytics research director. “But they’re not at all going to eliminate the need for ground stations.”
OPTICAL NETWORKS
A few major constellations with extensive funding, like SpaceX Starlink, Amazon’s Project Kuiper and the Pentagon’s Space Development agency, are rapidly adopting intersatellite links.
Other satellite operators are moving more slowly.
About a year ago, moves by the Space Development Agency and others made it seem like “we were on the precipice of a full-on shift to optical crosslinks being the norm,” Henry said. “What we have learned this year is that the traction towards laser crosslinks is still moving kind of slow outside of SDA, SpaceX and Amazon’s Project Kuiper. Other small satellite operators are still struggling chiefly with managing the size, weight and power of optical terminals.”
Optical terminal manufacturers have no doubt change is on the horizon.
“One of the greatest advantages of optical communications technology is its ability to transfer large amounts of data quickly and securely,” Tina Ghataore, Mynaric chief commercial officer, said by email. “While the adoption of optical communications in space applications is still in its infancy, the sheer number of satellite launches planned in the coming years will speed up the adoption of the technology. These satellites will need to have functional optical communications terminals to create the intersatellite links and transfer large volumes of data.”
Ground segment providers see something of a chicken-and-egg problem.
Widespread adoption of optical intersatellite links by small satellite operators will encourage mass manufacturing and lead to decreased size, reduced cost and further adoption.
Until the terminals have significant spaceflight heritage, though, small satellite operators may be wary of the technology, said Dan Adams, KSAT USA CEO. Earth observation companies designing their future constellations, for example, “may or may not be comfortable designing in the intersatellite link solution until they see that that solution is mature,” he added.
CONSOLIDATING TRAFFIC
Even if the change is not imminent, ground segment providers have thought extensively about how intersatellite links will affect their operations.
Satellite gateways may be consolidated at fewer sites, reducing the capital investment needed to maintain a ground network. And remote sites might become less important.
“Right now, stations in the Arctic, Antarctica or other remote areas don’t have good coverage for backhaul,” Dialani said. “The data has to be stored in the ground station and sent bit by bit over VSAT backhaul.”
With intersatellite links, a satellite over Antarctica could beam data to a satellite over Australia for downlink where fiber connections are plentiful.
That does not mean, though, that demand for Antarctic downlinks will disappear.
“We have customers that are willing to pay more to get data down at Antarctica because it provides an operational benefit,” Adams said.
While there may be some change in the geographic distribution of ground stations, “data still has to fit into the pipe between the satellite and the ground station,” Richins said. “And that pipe is limited. You’re still going to want to have many ground stations for resiliency and for overall throughput. With data volumes rising, it will take everything we have to bring all the data down in a low latency way that that makes sense.”
Optical ground terminals will be part of the equation.
“We are a few years away from the mass adoption of optical communications ground terminals,” Ghataore said. “However, we are ready to demonstrate the technology for customers that wish to explore it further.”
PARTNERSHIPS
Firms known for handling the satellite ground segment plan to establish alliances with optical and RF data-relay companies.
“RBC Signals is not a ground station company, RBC signals is a communication-as-a-service company, which means we use satellites when we need them, we use intersatellite links” like Inmarsat’s Data Relay Service, Richins said. “As more capacity comes online, we’ll offer it to our customers.”
Likewise, KSAT sees intersatellite links “as both a huge opportunity and potentially a threat,” Adams said. As the satellite communications market grows, KSAT has adopted a “network-of-networks” approach with its legacy ground station network, KSATlite, and partnerships with AWS Ground Station and Microsoft’s Azure Orbital.
“We also see that expanding into nodes in orbit, where the whole solution set can expand,” Adams said. “Whether you’re ingesting your data on orbit or at the antenna on the ground, it is all about getting data in a dynamic way back to the user’s mission operations center. It’s about optimizing the data flows, whether it’s across a terrestrial network of fiber and antennas, or through an on-orbit ingest point down through the antenna and across the network.”
This article originally appeared in the March 2023 issue of SpaceNews magazine.
