Fighting fires with drones

By Paul Brinkmann|February 10, 2023

Aerospace engineer trains as wildland firefighter to explore how it can be done

NASA aerospace engineer Marcus Johnson has cultivated a research expertise in drone technology, advanced air mobility and the new air traffic management techniques they will demand. Currently, he is focused on fully integrating drones into emergency response operations, especially against wildfires. Last March, Johnson, who lives in South Florida, became manager of the Advanced Capabilities for Emergency Response Operations program, or ACERO for short, which is funded by NASA’s Ames Research Center in Silicon Valley. Johnson trained as a wildland firefighter, completing physical endurance tests in the South Florida forests, to help him understand the challenges of bringing drones to the battle. I interviewed him on stage at AIAA’s SciTech Forum in Maryland in January. Here is our conversation, lightly edited.

Q: In terms of the Unmanned Aerial System Traffic Management, or UTM, we’re talking about managing a crowded airspace where you have hundreds or someday thousands of drones flying over a densely populated area, and then adding in air taxis carrying people. Tell us how the UTM works.

A: The UTM is an air traffic management ecosystem for small UAS at low altitudes. At its core, it’s really an information-sharing mechanism that relies on services provided by operators and UAS service suppliers. From the operator’s standpoint, or the aircraft pilot, their system really just needs to say, “This is my flight plan, and this is where I’m at.” The service supplier kind of does the rest. They are the companies who are FAA approved for Low Altitude Authorization and Notification Capability, or LAANC. They track the actual position, and they will note if you’re starting to deviate from your flight plan. And they let other service providers know, so anyone in that local vicinity can be notified that this aircraft is starting to deviate from its planned route and is in a non-conformance state — that this aircraft might actually cause a hazard to me.

There are other services that can be offered beyond just this basic strategic deconfliction, but what we can call conformance monitoring is the basis of the UTM. There is a remote ID that an aircraft broadcasts in terms of just its position, but the UTM is shared over the Internet as a cloud-based service.

What we’ve learned at low altitudes, having this type of network, is extendable to larger aircraft — whether it’s remotely piloted or with a pilot on board. At some point, we may have a single operator that may be controlling 10, 15 or 20 drones. So the systems themselves need to be able to detect if something is wrong. So the UTM is not just what’s onboard the aircraft, but also what is communicated over the network.

Q: You’ve also worked on aircraft control systems themselves in the past. How did you use algorithms that determine how a fly-by-wire system functions?

A: That’s going back a little further in my career, including my work for Boeing about 10 years ago, but control algorithms typically are the inner loop of the aircraft’s flight control systems, which basically stabilize the aircraft. And then there’s an outer loop, which focuses on the navigation of the aircraft. When the pilot pulls on the stick, control law algorithms are the programming, the logic, that tells the system how to control the flaps, or what to do with the ailerons. And they are important even for drones, because the system sees a set of waypoints along a route. The control laws will make sure that you are tracking that path as well as you can.

With any electric aircraft, even with a pilot on board, they would have pretty sophisticated control laws, because they have distributed propulsion and it’s not like a simple tube-and-wing configuration. So that takes some pretty fancy logic behind the scenes, in the system, in order to still make it reasonably flyable for a pilot.

Q: You’ve also worked on vertiports and the airspace management issues that will come into play around a vertiport. What are some of the frontiers of the science that you’re working on there?

A: Vertiports are an area where there’s a lot of interest today and a lot of open research to be done. In order to close the business case for many AAM operators, they’re going to require rapid turnaround and a high number of flights to drive down the price and allow them to really start making money. To get higher density or throughput at a vertiport, you either need a very big facility, or you start having things like automation — technology that helps assist operations. I had started at NASA a research area called the High-Density Vertiplex project that was focused on that automation and solutions that allow you to move aircraft across those FATOs, final approach and takeoff areas, as quickly as possible, and looking at what technology and what interactions do you need in airspace surrounding that vertiport. So, what types of information needs to be there? And how are the various systems in the aircraft, in the vertiport and the air traffic management systems going to interact with each other?

Q: Your current position, which is a relatively new project that began last year, is about applying some of what’s been learned about drones and airspace management to emergency scenarios, particularly wildfires. What led you into that work, and what are you learning?

A: The general premise is taking some of these advancements in aerospace and in aircraft autonomy and communications to support drone operations and starting to get those types of advancements into wildfire fighting, to use drones as a tool that allows us to fight fires and monitor fires and connect different parts of the firefighting operation in the field.

Q: And I heard you’ve trained as a firefighter in order to tackle this work. Why did you do that, and what are the advantages of such training?

A: The training gave me the basic qualifications to go out to the scene of a fire and deploy for two or three days or longer, and to actually fight the fire on the front lines, or whatever they need, as a Type 2 firefighter or crewmember. I received what they call a Red Card certification, which qualifies you for wildfire operations. I wanted to really understand what are the challenges and how the technology can be effective — not just from the 70,000-foot level, but for the folks actually on the ground.

They need information to make tactical decisions, such as where to set up a fireline as the fire is moving down a hillside, and maybe there’s a town on the other side of the hill. So, what direction is the fire moving in and do we need to try to stop it right here, or can it burn a little further? We can make predictions about where it’s going to go, given the fuels, the composition or dryness of the underbrush and leaves, and other fuels for the fire. We can also tell them what their available resources are.

Q: What is the potential for drones to be used in fighting wildfires?

A: Drones are really a potential game changer. We can use drones to set controlled burns, very precisely controlled, by dropping what’s called a dragon egg, which ignites when it hits the ground. By doing that over time in a controlled way, you remove the fuel that accumulates and allows these big wildfires to burn out of control in the dry season. We’re looking at how we can use drones to better manage millions of acres susceptible to wildfires.

Q: And you believe the wildfire example can illustrate how AAM can benefit society?

A: When you think of the broader picture of advanced air mobility, one of the big challenges is public acceptance, explaining why you’d want hundreds or thousands of new aircraft flying around. So I think what resonates is “how it helps my daily life.” Wildfires are really devastating communities, and fighting them requires a very collaborative environment. And so emergency response can be a trial run to test out how well some of this technology works before we get to commercial use. It’s a lot better selling point to the public for acceptance than saying, “Hey, you’re gonna get this pizza delivery faster with a drone.”

Q: You’re planning a test this summer to look at how a high-altitude platform could be flown over an active fire to provide communications.

A: Yes, the test will look at how to provide connectivity by flying a cell phone node over an active fire, which can be in very remote areas. This could be a gamechanger, not just for wildfires, but for all sorts of advancements in connectivity in post-disaster recovery, such as hurricane strikes that knock out communications. If we can accomplish this, there may be ways to also boost low connectivity in urban areas.

Q: You’ve done a lot in your career, and you’re only 37. What drives you and what has contributed to your success?

A: What really motivates me is making change that can benefit people. A lot of research I’ve done is geared toward safety. When I was working on the UTM, we wanted to make sure it wasn’t just about making money, but about providing aircraft and systems that can reach communities that maybe haven’t had air service, or to be able to fly doctors into remote areas, for example. Working for NASA, we never work alone, so I’ve worked with top-notch people, and I’ve been part of great teams. Personally, along the way, I’ve had great mentors, like PK, Parimal Kopardekar, who we call the godfather of the UTM.