Rick Robinson

Feb 7th 2022

Remote Sensing: The Close-Up View From Space


In 2018, as catastrophic wildfires raged across California and other Western states, hard-pressed firefighters got a hand from an unexpected source.

According to SpaceNews, satellites designed to provide warning of ballistic missile attacks were pressed into service to provide infrared imagery of the wildfires — remote sensing data that gave fire agencies a detailed, big-picture view of the blaze to guide them in deploying firefighters, water-bombing aircraft and other assets.

The assistance also highlighted an unexpected challenge. The computer software that handled the satellites and their warning data was proprietary, and the Pentagon and the contractors who developed the software had to work on the fly to convert the data into a form civilian fire agencies could read and interpret.

Tripping the Light Fantastic

The episode highlighted two things: the capability of space-based sensors in guiding the response to a real-world emergency, and the complex challenges that arise from technology that has both defense and civilian applications.

NASA defines remote sensing as simply “the acquiring of information from a distance.” For space sensors looking down at Earth, the distance ranges from a few hundred miles for satellites in low orbit to upward of 23,000 miles for satellites in geosynchronous orbits.

The information acquired at this distance is derived primarily from electromagnetic radiation — using visible light and its cousins at different wavelengths, such as infrared and radio waves. Photographs of Earth and its landscapes (and seascapes) from space are the most familiar of these. Anyone who has looked for their house on a satellite map, such as Google Maps, has experienced a taste of this technology.

In overall impact, these satellite map images can range from gorgeous to terrifying — sometimes both at once — and they also contain a vast wealth of detailed data. Remote sensors tuned to other wavelengths can provide a further wealth of detail that can either be converted to visible imagery for viewing or processed and analyzed by specialized tools.

The More You Know, the More You Need to Learn

The range and variety of these sensing tools and the tasks for which they can be applied are so wide, they almost defy any quick summary — as a glance at the NASA and Frontiers in Remote Sensing discussion of this technology makes clear.

Infrared observations of land and ocean surface not only provide direct temperature data but also a wealth of information on everything from crop health to ocean currents. Mining can be guided by hints of rare minerals in surface imagery. Frontiers notes that space imagery has even aided investigation of the COVID-19 pandemic, providing “datasets that utilize diverse targeted visualization to classify human environments,” which could then be mapped onto social, economic and other data sources to provide insights into how the virus attacks communities.

Sixty years of technology progress in space-based sensing from the first satellite imagery has paradoxically made the challenges of space sensing greater. The reason, per Frontiers, is that while technology progress can “improve the information content of the observations, the data is never fully sufficient to uniquely characterize all of the geophysical parameters of interest; the list of desired observables grows continuously with the advancement of science.”

Really, this is the whole history of scientific observation in a nutshell: The more we can see, the more we discover new things that we should be looking for.

In the case of space sensing, improved sensors allow us — and challenge us — to observe finer details, both in terms of size (finer image resolution) and detection of subtle details. To gain the full value of this wealth of data, it must be cataloged and cross-correlated, so people who use the information can find it when they need it.

Piercing the Veil of Secrecy

As our overall capabilities have grown, so have our defense-related capabilities — from the ability to find and identify a previously secret airfield to the ability to pinpoint a single armored vehicle, even when backed into underbrush in an attempt at concealment.

The overall effect of this capability has been positive. As the Defense Department notes, satellite observations “have reduced the ability of all countries to perform sensitive military activities undetected.” This is particularly significant in relation to closed societies: It has become vastly harder for anyone to build a secret base or conceal their military operations from the world.

At the same time, as the challenge of providing defense-satellite data to firefighters showed, the civilian-military overlap in sensing capabilities and requirements adds a further layer of complication to the overall problem of providing access to sensor information.

Of course, using and managing this fast-growing branch of our knowledge and capabilities is still a work in progress. Though we’re only at the beginning of grasping the full potential of remote sensing — and overcoming the challenges posed in balancing defense with other responsibilities — the future looks bright.

Are you interested in all things related to technology? We are, too. Check out Northrop Grumman career opportunities to see how you can participate in this fascinating time of discovery.