In September of this year, NASA again delayed the launch of the James Webb Space Telescope, pushing it three years past its initial launch date to 2021. With a massive gold-coated mirror three times larger than the mirror on the Hubble telescope it replaces, James Webb will use the most advanced imaging hardware available to peer into the cosmos. It is the size of a yacht, cost over $9 billion, and has been under development since 1996. In the same time frame, thousands of small satellites will have gone into orbit, each no bigger than a suitcase and costing no more than a few million dollars.
While James Webb probes into the deepest reaches of the universe, most of these small satellites will be looking back at our own planet. These satellites are part of the rapidly expanding Earth observation industry, and as the name suggests, their mission is to better understand the planet we live on.
In many ways, the technology on these satellites is just as impressive as the technology on the James Webb telescope. From an altitude of over 2,000 km, the cameras on today’s satellites are powerful enough to distinguish between objects smaller than a meter across. Some have hyperspectral cameras, which record the chemical fingerprint of the ground they scan to detect things like nitrogen deficiency in crops. Satellites equipped with SAR (synthetic aperture radar) can even see through clouds and the darkness of night to take their pictures of the ground.
And yet, satellite cameras still lag far behind the technology available on the ground. Even the iPhone 8 camera can capture more data per image than most satellite cameras currently in orbit. More powerful satellites exist, but they’re often like James Webb – the size of a bus with a multi-billion dollar price tag – out of reach for anybody outside the most well-funded space programs.
But the challenge isn’t in fitting satellites with more powerful sensors. The real challenge for small satellites is in getting the data they collect back to Earth. Operators could be putting higher-resolution sensors on their satellites, but the data transmission hardware on their satellites wouldn’t be able to handle the extra data generated, forcing them to leave much of their data in space.
To better understand the problem, consider the iPhone again. Imagine you’re on vacation on the other side of the world, You take a picture on your iPhone and upload it to Instagram, and in a matter of seconds, your friends back home can see the picture on their own phones. This instant connectivity is made possible by a global network of cell towers and fiber optic cables, sending vast amounts of data around the world at all times.
In space, there’s no 4G data connection like there is on the ground. Satellites are stuck in the dial-up era, transmitting their data with radio frequency (RF) technology that has hardly changed since the days of Sputnik. No matter how many terabytes of data their sensors can collect, RF limits the flow of data to the ground to a trickle. The bottleneck limits the amount of data satellites can collect and forces operators to wait hours if not days for their data to reach the ground.
To get the most out of Earth observation satellites, space needs a high-speed data connection just as much as we do on the ground. The solutions proposed are remarkably similar to the techniques used to connect the world below. Like the fiber optic cables that replaced copper wires on the ground, laser communication systems can carry 10 times more data than the radio frequency systems they would replace.
Another possibility would be data relay networks, consisting of networks of satellites that would transfer data between each other in orbit before routing it to the ground, essentially behaving like cell towers in space. Instead of waiting for a direct line of sight to a ground terminal that would receive a satellite’s data, satellite’s could offload their data to the data relay network when they would otherwise be idle, freeing up storage to collect more data.
Improving the connectivity of Earth observation satellites could have broad implications for the ground based economy. If weather monitoring satellites could get their data down faster, airplanes could save 20% on fuel costs by more efficiently routing around storms. With larger data sets from hyperspectral satellites, mineral prospecting, agricultural output, and forestry management could all be optimized. Earth observation satellites could also help to mitigate our environmental impact on the planet, monitoring soil contamination, air quality, and water pollution. At a time of increasing resource scarcity, Earth observation satellites could be the key to reducing waste and more effectively managing the resources at our disposal. But to unlock their true potential, satellites are in critical need of a high-speed data connection to the ground.
One day, humans could be an interplanetary species colonizing the distant planets seen by the James Webb Space Telescope. Until that day, we need to find ways to tap into the potential of the planet right below our feet.