The snow-dusted peak of Mount Wilson in California has been home to many famous observatories. Until 1949, its 100-inch (2.5-meter) Hooker telescope was the largest aperture telescope in the world, and in 2004, its CHARA array became the world’s largest optical interferometer.
Now, two new observatories are being built there that, while not focused on the stars, might prove equally historic. They could house Facebook’s first laser communications systems designed to connect to satellites in orbit.
Construction permits issued by the County of Los Angeles show that a small company called PointView Tech is building two detached observatories on the mountain peak.
PointView is the company that IEEE Spectrum revealed last year to be a previously unknown subsidiary of Facebook working on an experimental satellite called Athena. In April, PointView sought permission from the U.S. Federal Communications Commission to test whether E-band radio signals could “be used for the provision of fixed and mobile broadband access in unserved and underserved areas.”
That application was still pending at the FCC before the current U.S. federal government shutdown took effect, but it and other public documents and presentations now strongly suggest that PointView is planning to utilize laser technology, possibly both in Athena and future spacecraft.
Facebook has long been interested in free space optical, or laser, communication technology. Lasers are able to support much higher data rates than radio transmitters for a given input power, and their signals are largely immune to interference or hacking, although clouds can be problematic.
Although Facebook developed millimeter-wave E-band links for its stratospheric Aquila drones, it was also experimenting with air-to-ground laser communications before it canceled its drone program last June. The laser tests, which used technology supplied by German company Mynaric, succeeded in establishing 10-gigabit-per-second links between a ground station and a light aircraft flying overhead.
“We proved that a link could be re-established near instantaneously without any discernible downside,” Paul Cornwall, a Mynaric spokesperson, told Spectrum. “That’s pretty key for people looking to establish [high altitude or satellite] constellations.” However, the company would neither confirm nor deny that it was still working with Facebook.
Planning documents show that construction work on PointView’s Mount Wilson observatories began in July and passed inspection in the middle of December. If the observatories are part of a laser satellite installation, they might use an optical ground station conceptually similar to Mynaric’s. This transmits its own laser beam up into the atmosphere for a drone—or potentially a satellite—to lock on to.
Facebook itself did not immediately respond to a request for comment on this story, and the Mount Wilson Institute, which manages the observatory site, would only say, “The PointView Tech installation is not yet complete.”
However, scientific papers authored by Facebook researchers suggest the company is committing resources to orbital lasers. In a series of papers published in 2017 and 2018, engineers Raichelle Aniceto and Slaven Moro subjected multiple components, including an optical modem, to radiation similar to that experienced on orbit.
“The results were evaluated for potential space mission applications,” they wrote. “We intend for these results to be of use to the satellite and aerospace industries and to move forward Facebook’s mission of connectivity.”
Both engineers work at Facebook’s Connectivity Lab in a suburb of Los Angeles, the same location where PointView is based. Moro’s LinkedIn page says that he is working on satellite communication system architecture design, and optical and millimeter-wave communication products. Aniceto’s page reveals she is testing hardware for development of an optical communications modem system.
In a TedX talk in Boca Raton, Fla. last October, Aniceto enthused about the game-changing potential of laser satellites for developing countries. “Internet access can empower these populations by providing them with opportunities for education and for developing businesses,” she said. “Laser communication is a viable technology to connect the unconnected, especially for people in very hard-to-reach places.”
Aniceto described how an Internet satellite in a geostationary orbit could use eye-safe, near-infrared lasers to achieve much higher data rates than a similar radio-frequency satellite, even while reducing its size, weight, and power.
She also said that laser satellites would be especially interesting to newcomers because “many of the major players in the industry already own the most ideal [radio] frequencies” while “laser communication frequencies are currently not regulated.”
Perhaps coincidentally, PointView’s application for its Athena satellite contains confidential redacted sections that PointView claimed “specifically concern the use and implementation of technologies that are not regulated by the [FCC]… [and]… information controlled by the Export Control Regulations.” A laser tracking system would fulfill both requirements.
The geostationary setup Aniceto describes would differ considerably from the laser system Facebook tested with Mynaric. On the plus side, using a geostationary satellite would mean that ground-based observatories would not need to track rapidly moving objects, such as drones or satellites in low Earth orbit. However, even tightly focused laser signals would spread out and become weaker on the long 36,000-kilometer journey from a geosynchronous orbit.
“The light from an optical beam… would actually spread to encompass a fraction of a city,” said Aniceto. “[And] if the satellite and the laser communication were off pointing this beam by even just one degree, it would completely miss the planet.”
Although the system Aniceto described may differ from the one Facebook is developing, she concluded her speech by saying: “Join me as I continue to develop new technology or as I find alternative ways to use existing technology to make the greater impact of connecting the unconnected.”
Zac Manchester, an assistant professor of Aeronautics and Astronautics at Stanford University, told Spectrum that he has no knowledge of any Facebook satellites but is aware that the company has been working on laser communications. “I’ve seen some of their work in the area,” he said. “It’s very cool.”
PointView said in its filing that it expects to launch Athena early in 2019.