Building CAO
28th May 2015

Building CAO

Food for thought
Animal Ecology
Climate Change
Land Use
United States
Imaging Spectroscopy
Laser Scanning

On May 1 2015, the third generation Carnegie Airborne Observatory (CAO) was unveiled at the Hiller Aviation Museum in San Carlos, California to a crowd of conservation, science, aviation and technology enthusiasts. CAO-3 stands out as one of the most advanced Earth mapping and data-analytics platforms operating in the civil sector today. Here’s the behind-the-scenes story of the CAO.

The development of the CAO started back to 1996, when founder Greg Asner was head-deep in his PhD research, using imaging spectrometers to probe the plant ecology and soils of deserts and tropical forests. Imaging spectroscopy is the study of how solar radiation interacts with matter (like plants, soils, rocks, and buildings) in ultra-fine spectral detail well beyond our visual range. Today, it’s best known use is for mapping chemicals in the environment. To do the work back then, Asner relied on the Jet Propulsion Laboratory’s (JPL) Airborne Visible and Infrared Imaging Spectrometer, or AVIRIS, which was a pathfinder for the use of spectroscopy in Earth science.

By 1998, Asner and JPL colleagues including Robert Green and Michael Eastwood had taken AVIRIS to Hawaii onboard a converted U-2 spy plane and later on a Twin Otter. Their high-flying studies took years to yield the approaches in use today by CAO and others worldwide. Hawaii proved to be a critical “microcosm” because the islands harbor more than two-thirds of the major types of ecosystems found on Earth. Hawaii was their outdoor laboratory.

JPL's AVIRIS with Carnegie's LiDAR in Hawaii

JPL’s AVIRIS in Hawaii, circa 2003

By 2005, Asner had a late-night idea to fuse imaging spectroscopy with a very different approach to mapping Earth. Laser-based imaging had emerged with the advent of Light Detection and Ranging or LiDAR technology, which was making it possible to map Earth features in 3-D. Asner’s idea was to integrate the strengths of imaging spectroscopy, which is best suited for mapping chemicals, with LiDAR that best probes the structure of Earth’s surface including trees, buildings and mountains. The fusion idea was an untested undertaking, and Asner’s only ear was the W.M. Keck Foundation, which has a history of taking on bold, high-risk scientific ventures.

By late 2006, the data fusion idea solidified with the launch of CAO-1, comprised of a Visible-to-Near-Infrared (VNIR) imaging spectrometer and a simple LiDAR system. CAO-1’s compact system was designed to fit into a small aircraft, such as the Piper Navajo that became the CAO-1 workhorse.

CAO-1 Piper

CAO-1’s Piper Navajo in Hawaii, circa 2007

The team was small – just three staff, and the stakes were high scientifically and programmatically. Aircraft engine flareups, failed sensors, landing gear problems, sideways rain, airsick crew, and more: The CAO-1 start-up felt more like airborne swashbuckling than it did science.

CAO-1 inside the cramped aircraft cabin

CAO-1 inside the cramped aircraft cabin

CAO-1’s unique results eventually started to trickle in by 2008, mostly focused on ecosystems in Hawaii. At the time, invasive species had fully emerged as a hot conservation science topic, and both the State of Hawaii and US Forest Service engaged the CAO-1 team for high-tech help in identifying where unwelcome plants might be found. By 2008, CAO-1 was also operating in South Africa’s savannas with their National Park Service, and by 2010 it was flying over Madagascar and Colombia in support of booming forest carbon projects.

Through the CAO-1 effort spanning 2006 to 2010, it had become clear that the team’s science had pushed the technology as far as it would go. Much more capability was needed to advance Earth science and conservation at large geographic scales.

With support from the Gordon and Betty Moore Foundation, John D. and Catherine T. MacArthur Foundation, and William Hearst III, the team built and launched CAO-2 in May 2011. CAO-2 carried the first version of the Airborne Taxonomic Mapping System or AToMS. To build AToMS, long-time colleagues Asner, Green and Eastwood combined Carnegie and JPL efforts to build the first “high fidelity Visible-to-Shortwave Infrared (VSWIR) imaging spectrometer”. They paired the VSWIR spectrometer with an extremely sensitive dual laser LiDAR. CAO-1’s VNIR spectrometer was also rebuilt for improved performance, and integrated with the VSWIR spectrometer and new LiDAR. The new AToMS payload was large, and a much beefier aircraft was needed to carry it. A Dornier 228 was selected to host this trio of sensors and its associated batch of computers, hardware and peopleware.

CAO-2 at its launch in May 2011

CAO-2 at its launch in May 2011

CAO-2 operations went viral, with missions to the Peruvian Amazon, Panama, Costa Rica, California and elsewhere, enabling hundreds of scientific discoveries, conservation outcomes, and new resource policy developments. Among the biggest of technical breakthroughs was a new ability to map the carbon stocks and biodiversity of whole countries.

Along the way, CAO-1 and 2 published more than 150 scientific articles with colleagues from dozens of countries, and the CAO staff trained a huge number of people. Discoveries continue to flow from CAO-1 and 2 at a rate that defies the science community’s rate of uptake.

Despite these and other successes, leasing an aircraft severely limited in the team’s ability to operate where and when they needed the science to generate the most impactful discoveries and conservation outcomes. At that point, it was decided to purchase a plane and retrofit it with an even more advanced airborne laboratory. CAO-3 was completed on May 1st 2015, thanks to some very dedicated CAO engineers and a catalytic donation from long-time CAO supporter and Carnegie Trustee William Hearst III.

CAO-3 is more than a new airborne laboratory. It is an entirely new way of operating. Even so, the new lab is simply beautiful and high-tech, as captured in here by Los Angeles photographer Spencer Lowell.

Crew Cabin in CAO-3

Crew Cabin in CAO-3

CAO-3's Instrument Bay in the Back of the Aircraft

CAO-3’s Instrument Bay in the Back of the Aircraft

CAO-3 purrs with data streams that exceed a terabyte per flight. The big data hose is now truly at full throttle. What’s next for the program?  Ecuador, Borneo, California, and more.  Stay tuned.