Chad R. Frost supervises the Autonomous Systems and Robotics (ASR) technical area in Ames Research Center's Intelligent Systems Division. ASR staff develops advanced automation and control technologies to enable safer and more efficient aircraft, make robots smarter and more capable, increase scientific productivity, and allow spacecraft to explore the universe with greater independence.
NASA Tech Briefs: What are some of the advanced aircraft design elements that you're working on, designs that may only exist on a computer?
Chad R. Frost: We're investigating all sorts of interesting concepts aimed at increasing efficiency and safety of aircraft: wings that can change shape, how to integrate an ever-increasing number of control systems on an aircraft, and how to make aircraft flyable even when they're severely damaged. Some of these concepts indeed exist just in the computer, but others have made it all the way to full-scale flight tests, and there's just an amazing spectrum of things that are coming down the research pipeline that we hope will someday make it into the commercial world and do wonderful things for the aircraft that we spend so much of our time on these days.
NTB: How would you say an aircraft is safer and better than, say, 5-10 years ago? What are the exciting developments?
Frost: Even in the span of 5-10 years, there have been quite a few changes. I think aircraft coming off the line today are better than their predecessors in lots of ways. Since we're focused on the control aspects in my staff, I can talk about that in a little more detail. Fly-by-wire [replacement of manual flight control of an aircraft with an electronic interface] is now pretty much ubiquitous for big, commercial transport aircraft, and for an aircraft designer, that gives you a great deal of flexibility. The basic airframe can be less stable, potentially more aerodynamically efficient, while maintaining good handling qualities for the pilots. Aircraft can handle consistently across the whole flight envelope, and since a computer is helping out, control surfaces on the aircraft can be used in really novel ways that they couldn't before. the mechanical connection between the pilot's stick and the control surfaces is removed, as is the case for fly-by-wire, the control surfaces can more easily be used in new combinations. As an example, ailerons might be "reflexed," or deflected slightly upward, to improve aerodynamic efficiency in high-speed flight.
Now we have aircraft that can fly even very complex maneuvers, especially at low speed that just really wasn't possible previously, and of course, now they can use the autopilot and the flight management system to do very sophisticated navigation. And we have digital communications into the cockpit for functions like traffic and weather. Even five years ago, that really didn't exist in any substantive way. That's all come about fairly recently, and is having a transformative effect on how aircraft operate on a daily basis.
NTB: What's the current state of unmanned aerial vehicles?
Frost: That's a very active area of research around the world. As you know, it's driven by both military and civilian needs. From NASA's standpoint, we have interests both in developing and operating unmanned aerial systems to support science missions, and in the basic and applied research needed to ensure the UAS (Unmanned Aircraft System), both NASA's as well as others, will eventually be able to safely integrate into the national aerospace system. That's our big emphasis now: These aircraft need to be able to operate in the national aerospace system integrated with commercial traffic, integrated with general aviation, and be able to carry out missions in a very safe way.
Now, our work really covers both aspects. We've developed software systems to help distributed mission operations teams manage their science campaigns, for example for the western states' wildfire missions that we've flown the last several years, as well as for the onboard autonomy and control software that you need to give unmanned aircraft systems greater robustness to failures, and the ability, say, to track phenomena while flying around --and do that autonomously and, of course, to work together to solve complex problems.
NTB: You mentioned software. How important of a role does software play in flight control systems?
Frost: I'm somewhat biased. I would say that software really is the role in flight control systems. Hardware is a distant second. I'm a software guy, so I'm a bit biased about this, but I think it's fair to say that software is playing an increasingly large role in control systems, both for aircraft and for spacecraft, and for several reasons. Where we're looking somewhat into hardware advances, some of those advances are smarter bits of hardware. And that typically means embedded software into that hardware. We're also looking at distributed systems of hardware, and now that we have those embedded systems and the distributed systems, plus the original control software you'd normally need, you now have to have the software required to interconnect all of these systems of systems, plus the additional software required to meet the expectations not delivered by hardware. Of course, that includes software to deal with fault detection and fault management from this now very complex system. You can sort of see this mushrooming effect, and software is really central to it all, and evermore so. Being a software guy, I'm somewhat biased, but I really think that software is the central role in flight control systems and for the future.
NTB: How much of a role do you play in writing the software itself?
Frost: I've been a manager for some years now so my hands-on-the-code is not what it once was. I have a whole collection of little software utilities I've written over the years, mostly to do simple analyses and stitch together other pieces of software, or manipulate files the way I want. I think that's true for most of us. We make these little tools all the time, and occasionally they turn into something bigger.
As a bigger organization, we're really trying to build very open tools whenever possible, to make them as broadly useful as we can, and sometimes that becomes a real challenge in itself. Should you make something that's very useful but does just one specific thing, or should you invest more time to build a more general solution? I think that's really reflected by my team's leadership in NASA's open source initiative. We have a considerable number of software tools and libraries available under the NASA open source agreement as well as more typical, collaboratively developed projects that are out there, where people can contribute as well as use the software. So no, I don't have a day-to-day, hands-on-the-code kind of experience that I did when I was younger and just working as an engineer on projects, but I like to think that I have maybe more instruments in steering our directions than I once did.
NTB: What is your day-to-day work with flight control systems?
Frost: I'm really just a lowly manager these days. I don't have a lot of "hands-on" on any single project, and I've been in that kind of a role between the last 5-7 years, I'd say. So my daily involvement isn't really what it once was, and I miss that. I do try to participate in our project meetings, both at the beginning and the middle and the end of the process. I think the initial brainstorming about how to solve a problem, or what approaches we might use to achieve our research objective, is really quite fun and satisfying.
During the life of a project, there are also many opportunities for me to learn from our researchers and engineers, and as a project comes to fruition, I'm typically looking around at how we can get whatever we have developed out into the public, where the taxpayers' investment in NASA can see some return. These days I get my satisfaction from being involved in all these phases, even though I'm not necessarily developing control algorithms or systems myself.
NTB: You've done a lot of research simulating the handling qualities of spacecraft, including lunar landers. What conclusions have you been able to draw from this kind of work?
Frost: That's one of the ways that I've tried to keep my foot in the technical world a little bit. NASA started this project because no work had really been done, since the Apollo era, on how spacecraft should fly, and even then it was quite specific to the Apollo spacecraft configuration. We wanted to establish boundaries more generically for what constituted good spacecraft handling qualities. There are several papers now written on this, and there were a lot of co-investigators on this project: D. Bilimoria, Eric Mueller, Randy Bailey, Bruce Jackson, and myself.
For crewed spacecraft, even in the case of a nominally, fully automated spacecraft, it's vitally important to consider how it will fly under the control of a human pilot. In that particular case, the human might well be trying to fly it under the worst possible conditions because the automation would've failed for some reason. Thus it's important that the spacecraft fly well even in its most degraded state. We found that there's definitely a sweet spot in the control characteristics for lunar landers. Piloting spacecraft is definitely aided by intuitive displays in the cockpit. Astronauts truly have the "right stuff" when it comes to flying spacecraft. None of that is a particularly new revelation. It mostly backs up what's been observed or obtained through early experiments in the Apollo days and somewhat worked with the shuttle. The details that we published in these papers that I mentioned are what will be useful over the long-term, as NASA and our commercial providers in the future work to define how spacecraft really should be.
NTB: What other current or recent projects have you begun with spacecraft design?
Frost: We're very involved in NASA's small spacecraft projects. My team's responsible for flight software on the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission, as well as mission operations and ground data systems, and we had some of those same roles on the Lunar Crater Observation and Sensing Satellite (LCROSS) mission. We're frequently developing new mission and technology concepts to propose to NASA's calls as well as other government calls, or potentially, to develop these with commercial partners.
Lately, there's been a lot of interest in highly distributed swarms, or constellations, or what's called fractionated systems, of very small spacecraft. And what kinds of new and novel missions these microspacecraft can enable. , we'll have "spacecraft -on-a-chip" -- in the meanwhile, we're trying to make every part of the spacecraft smaller, lighter, and more capable. There's ongoing work to develop spacecraft that use the processors and systems and sensors from smartphones, and to develop multi-functional components such as solar panels integrated with other systems. We're really involved in what I think is the cutting-edge of the spacecraft we're going to see in orbit in the next several decades.
NTB: What's the most exciting project that you're working on currently?
Frost: We're involved in so many different things, and there are so many exciting aspects to all of them. It'd be hard to pick anyone. I'll go with a recent one just because it is really exciting. One of our teams, led by Dave Smith, has developed a system called the Emergency Landing Planner, or ELP, and it's designed to integrate into an aircraft's flight management system. Say an aircraft has a failure or is damaged in some way while en route: Right now the pilot needs to figure out what's the best airport to land that aircraft at, subject to what the aircraft can do, what airports are within range, what wind conditions and weather conditions prevail, length of runway, many competing factors that a pilot needs to think through. Often now, to talk on the radio with air traffic control to figure out "Ok, what are the winds at that potential airport?" and if the winds are too high, or are in the wrong direction, now he's got to go look at a different airport. It is quite a complex task performed under very trying circumstances. If you've got a fire in the cargo hold, you want to put that airplane on the ground right now, and figuring out where to go and what airport you can actually reach is really a challenge. planner takes these various factors into consideration, and proposes possible routes and landing sites to the pilot, ordering them according to estimated risk. The ELP was developed from the start to integrate directly into existing commercial aircraft cockpits, using a standard CDU.
This system that's been prototyped and now tested in fairly high-fidelity simulation has just had outstanding results. We got wonderful comments back from the line pilots who came in and tried it out. It was developed from the get-go to be easy to integrate into a modern, commercial aircraft. It'll fit right into existing systems. I think it's got great potential. I think it's something we'll see in lots of cockpits very soon. As compared to the more research technology that we often are developing, this is stuff that is appropriate, useful, and it's going to be out there soon, and I'm very excited by it.
NTB: What are some of the other commercial applications with your work with NASA?
Frost: I don't want to get into too many gory details of the specifics, but I'm frequently talking with potential partners and collaborators in academia, other government agencies, and of course, industry. NASA has unique experience that we can bring to the table to help others succeed, and of course, we have a large and increasing body of software and technologies that can be licensed, or in more and more cases, downloaded directly in the form of open source. Some notable examples of our recent commercial technology transfer and partnerships include our imaging and computer visualization work that we've done with Microsoft's Worldwide Telescope, Google's Moon and Mars 3D, the Gigapan Robotic Camera and backend server software, and many others. It's very exciting for us to work with partners out there that get our technology out into the public and have it do great things, and we're always looking for more opportunities to do exactly that.
NTB: I saw that you've worked specifically with helicopters early on. I'm interested in how that came about and particularly what your role was in the first human-powered helicopter?
Frost: That goes back some time, I guess, I worked on the human-powered helicopter at Cal Poly San Luis Obispo. This was called the Da Vinci Project. I worked on it from about 1985-1990 when I was an undergraduate there. It resulted in the world's first human-powered hover in, I think, 1989. I helped build, design, and test a lot of different pieces of the various iterations of that helicopter that we went through.
NTB: What exactly is a human-powered helicopter?
Frost: Exactly what it sounds like. Trying to achieve vertical flight solely under human power. Everybody probably is familiar with Gossamer Albatross, Gossamer Condor, Paul McCreedy's exciting human-powered airplane projects, and the human-powered helicopter attempts over the years, or really, directly inspired by the successes of the human-powered airplanes. It's arguably a harder challenge to go straight up, and it took us a lot of years and a lot of hard work, just to get a few inches off the ground for a few seconds, and various people have tried over the years to get higher and farther into the air for longer periods of time, but it's just a very difficult challenge. In the last couple of years, I've gone back to universities to talk with a new generation of students who've revived the project. It's really exciting to talk with the kids about this because they haven't figured out just how hard it is, and they're still full of enthusiasm and excitement for it. You learn so much going through the attempt that I would never try to dissuade them. I think it's very exciting to try even if it's an almost impossible task. Certainly, I learned a lot from it. Certainly those who worked on it when I was there did. I was never one of the chief engineers on that project, but I spent a lot of blood, sweat, and tears over those 5-6 years that I was involved.
NTB: I'm also interested in some of your early work as an aircraft component designer and manufacturer. Were there any lessons learned that you can apply today?
Frost: My bachelor's degree arrived just in time for a major aerospace industry downturn. Our industry is cyclical as anyone who's been in it for any length of time has figured out, and I ended up finding a job at a very small manufacturing company, which in retrospect, proved to be a great foundation for an engineering career. The company I started out with had three engineers and a total of about 50 people in it, so the engineers really had to be able to do anything, and we were intimately involved in every aspect of the process: the design, development, manufacturing, as well as sales and support. I learned a tremendous amount in the years that I spent at that company. It was a great training ground, and I really enjoyed it. It ultimately led me to go back to school to get an advanced degree, and my faculty advisor had a really good relationship with the folks here at Ames Research Center, specifically in the army, NASA, flight control, and cockpit integration branch, so I ended up working there as a summer student after about 5-6 years in industry. Ultimately, I ended up doing my master's research helping to develop CONDUIT, the Control Designer's Unified Interface, which was a project led by Dr. Tischler from Army, and that tool went on to win a bunch of awards. It's now used by most of the commercial and government aircraft developers, and that really is what got me into the helicopter flight control design side of things, as well as software and ultimately my career here at NASA.
NTB: What's next for you? What are you currently working on this year? What are your 2011 goals?
Frost: Right now, our biggest goal, given the interesting situation that our industry finds itself in, is to keep the projects we have going through whatever comes in 2011. Obviously, we're waiting to find out the outcome of NASA's budget and how Congress and the president work that out, so that we have a clear direction for the agency in the next few years. Obviously, there's a lot of discussion that has to happen before that's fully resolved, so we're trying to make all the plans that we can with the information that we have so that we can continue to develop the technologies that will be useful to NASA's future roles, missions, obviously to the taxpayer, who ultimately is our customer. Right now, there's a lot of very interesting things happening. First, on the aeronautics side of NASA, as well as science, we're involved in developing adaptive flight control that will someday make aircraft safer and more efficient. We're working on a variety of spacecraft projects that will launch in the next several years and produce very interesting scientific data. We're waiting to see what the future of commercial launch services looks like, and figure out whether we can help out and be relevant to that. So there are lots of challenges, and in those challenges, there's always opportunity.
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