The mass budget tells the story, and so does the data budget. A modern high-resolution or SAR imaging satellite can collect terabytes of data per orbit. Getting that data to the ground is the choke point: traditional radio downlinks, constrained by spectrum and antenna size, simply cannot empty the buffer fast enough. The fix is to stop using radio for the heavy lifting and use light.
MIT's grant US10205521B2, "Network of extremely high burst rate optical downlinks" (issued 2019), is foundational work in that direction. Its CPC tags are a free-space-optics roadmap: H04B 10/118 and H04B 10/1121 (free-space optical transmission), H04B 10/29, 10/40, 10/61 (optical link components and reception), H04J 14/02 (wavelength-division multiplexing), and H04B 7/18513 (satellite link). The named inventors — including Don Boroson, who led NASA's Lunar Laser Communication Demonstration — are the people who effectively proved space laser comms works.
Here is the mechanism. A laser downlink encodes data onto a beam of light and aims it at a ground station. Because optical wavelengths are vastly shorter than radio, the beam can carry far more information and be focused far more tightly — which is both the advantage (enormous bandwidth) and the challenge (you must point the beam with extraordinary precision, and clouds block it). The "network" and "burst rate" framing in the patent addresses the practical answer to clouds: don't rely on one ground station; build a network, and dump data in high-rate bursts whenever a satellite has a clear line to any of them.
Reusability changed the math for launch; optical comms is changing it for data. The same imaging and constellation businesses covered elsewhere on this site are bottlenecked not by how much they can see but by how much they can send home. A high-burst-rate optical downlink widens that pipe by orders of magnitude, which is why laser terminals are proliferating across new constellations and why inter-satellite optical links — the cousin of this downlink work — are becoming standard.
The scope note: this is a 2019 grant from a research institution, foundational rather than product-specific, and the cloud-availability problem it addresses by networking is real and unsolved in the absolute — light still doesn't go through weather. The patent describes the architecture for working around it; it does not eliminate the physics. And a method claim is not a fielded terminal.
For the comms lane, the lesson is to watch the downlink, not just the sensor. A satellite's usefulness is capped by what it can return to Earth, and optical downlinks — plus the optical inter-satellite links that route data to a satellite over a clear ground station — are where that cap is being lifted. The patents here are old enough that the technology is now arriving in fleets; the bottleneck is finally moving.