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10. 406 MHz | NASA's The Invisible Network Podcast

Season 1Episode 10Dec 5, 2019

Amidst the grandeur of spaceflight, there is a tiny bit of technology that, if not for its major role, might otherwise go unnoticed: distress beacons. This NASA-developed search-and-rescue technology could be life-saving not just for astronauts, but for travelers across the globe as well.

plane crash in Alaska

plane crash in Alaska

NARRATOR

Freytag’s pyramid cannot be climbed. It is not at Giza or Chichén Itzá. It is a structure, but not one used by architects like Gehry or Lloyd Wright. Developed by German playwright Gustav Freytag, it is a method to divide a five-act play into its component parts.

Dividing a play into neat categorical pieces isn’t easy, nor is it always possible. Yet, there’s something so human about attempting to bring order to the chaos around us. Freytag’s pyramid is one way to break down the complexities of the theatre. By bringing a play’s components into sharper focus, we can see the intricacies and subtleties of the work.

NASA is no stranger to organized chaos. We’re an agency of a thousand missions, each with a thousand milestones and a million little mountains that must be climbed. Among these tasks are dependencies, actors that can only find their mark after their neighbor has taken theirs.

In this play, there are big roles and little roles. There are divas belting arias centerstage, comics with just a line or two and stage hands holding painted flats in the background. There are understudies and swings prepared to step in should someone take the phrase “break a leg” too literally.

When seen together, these players tell the full story — the completed drama — a resolution to the chaos.

In Freytag’s pyramid, we begin a story with exposition. We introduce the major characters. For NASA’s voyage forward to the Moon, it’s familiar faces, ones you’ve probably heard of or encountered: a spaceship named Orion on a mission called Artemis, both with eyes set on our nearest celestial neighbor, the Moon, hoping to establish a sustained presence there.

Then comes the rising action. For NASA, the rise is literal. It’s an ascent to the heavens aboard the Space Launch System, the largest, most powerful rocket to be built.

At the climax — the turning point — our astronauts land on the Moon. They plant a flag. They make discoveries or prospect for resources. Finally, they return their eyes back towards our big blue marble.

Then comes the falling action — once again this is literal. The Orion capsule streaks through the sky like a falling star, red-hot as it descends through the atmosphere at many thousands of feet per second.

And then, finally, the dénouement.

The dénouement is where scattered pieces of plot assemble to form the complete picture. It isn’t necessarily a time for reflection; that often comes after the play is done. Rather, it’s the moment where the final pieces of the story come together — the moment the curtain falls.

For NASA, hundreds — if not thousands — of pieces comprise the dénouement of the Artemis missions. There’s the graceful unfurling of parachutes. There’s the sway of the capsule in the turbulent air. There’s the splash of the ocean as Orion hits the water.

Then there’s egress — astronauts emerging from their metal cocoon. They’ll hop in big, orange rafts; inflate their life preservers. If you look close enough, you’ll see a little blinking light on their life vests. It’s coming from a device no larger than an old flip phone from the ’90s.

I’d like to talk about that tiny piece of tech — that small, yet significant piece of the puzzle lost somewhere in the dénouement.

I’m Danny Baird. This is the Invisible Network.

The Cospas-Sarsat program, an international effort to provide first-responders with satellite-aided search and rescue data, began as a collaboration between Canada, France, the former Soviet Union and the U.S. in 1979. Since its founding, the program has grown to include 45 countries and organizations worldwide.

NASA’s Search and Rescue, or SAR, office, has served as the technology development wing of the Cospas-Sarsat program since its inception. It developed and tested the concept for the search and rescue network, including the space and ground systems. It also developed the technology behind (and requirements for) the commercially manufactured beacons that relay distress signals through the network.

The original architecture of the Cospas-Sarsat network, still in operation, uses ground stations in tandem with geosynchronous and low-Earth orbit satellite instruments to detect and locate distress beacons. Geosynchronous instruments, about 22,000 miles overhead, alert the system when a beacon is activated anywhere in the world. Low-Earth orbit instruments hone in on the precise location where that beacon was activated using a method called Doppler shift geolocation.

The Doppler shift is a characteristic of waves described by Austrian physicist Christian Doppler in 1842. The frequency of a wave, such as a sound wave, decreases as its source moves away from you and increases as it moves towards you. Think of the wail of an ambulance as it passes by. The siren sounds more shrill as it moves towards you, but lowers in pitch as it moves away. That is the Doppler effect.

Low-Earth-orbiting search and rescue instruments use this characteristic to locate a beacon on the globe (hence Doppler shift geolocation). As they approach and pass over a distress beacon, the frequency they receive from the beacon rises and falls. Once the search and rescue network receives a few pulses of a distress beacon’s signal, (at 406 MHz, the internationally protected, or reserved, search and rescue frequency), the system calculates the location of the beacon by analyzing how much each signal has risen or fallen. The more pulses it receives, the more accurate the location it predicts. The more accurate the location, the better the information passed to first responders.

The satellite system recently underwent an upgrade, but more on that later. First, let’s talk about the beacons that NASA developed to send signals through them. There are three types:

The first are for personal use. Personal locator beacons are compact distress beacons that can be taken on a hike or a long journey. They’re perfect for adventurers and travelers of all stripes, for example, snowmobilers in the Alaskan tundra or hikers in national parks.

The second are for nautical use. Emergency position indicating radio beacons, may be found on cargo ships, yachts, sailboats, fishing boats and maritime vessels of all sorts. They’re often a little bigger than personal beacons and designed to float. Some even activate automatically when exposed to water.

Emergency locator transmitters, or ELTs, are for aviation. All aircraft from commercial airliners to homebuilt aircraft should have one installed. ELTs have an antenna fixed to the outside of the plane’s fuselage with a wire that runs into the unit. The unit itself is equipped with a sensor that automatically activates the device during a crash.

These three types of beacons were developed by NASA for the international search and rescue effort. Their manufacturing requirements and standards were passed to commercial industry, so that they may be made available to the public for purchase. Search and rescue technologies are one of the many ways that NASA shares its wealth of expertise for applications outside of spaceflight.

Dan Lockney, Technology Transfer Program executive, explains more.

DAN LOCKNEY

Every time NASA conducts a mission, we develop new technologies and it’s my office’s job to look at those new technologies and figure out how they can be used outside of their original intended purpose. And, generally speaking, they become new industrial applications, new consumer goods, products and services that make our lives better. A spinoff is a technology that has left the agency and turned into a new product or service in the marketplace.

So, spinoff and tech transfer is in the agency’s foundational legislation — that congress had the foresight in 1958 to say, “Don’t just blast money off into space — and these technologies into space — but make sure they come back to Earth in the form of practical terrestrial uses.”

While it’s our legislative mandate, it’s also the right thing to do — to make sure we repay the nation’s investment in this aerospace research and maximize that investment by making sure that the technologies we develop also pay dividends in the form of these commercial products and services.”

NARRATOR

Aleknagik, Alaska, has a population of about 250 residents. Suffice to say, it’s not a populous city, but a remote one. Traditionally, Alaskan natives used Aleknagik’s lakes and rivers as fishing camps during the summer. The word Aleknagik translates loosely to “wrong way home.” Those returning to their homes in the fall would often find themselves swept up in the tides and fog, ending up off track in Aleknagik Lake.

Looking at photos of the vast, beautiful wilderness around Aleknagik, it’s easy to see how one could accidentally take the wrong way home and find themselves lost among the hills and mountains and forests.

Sean O’Keefe served as NASA’s administrator from 2001 to 2004. During his tenure, he reduced a cost overrun on the construction of the International Space Station, saving taxpayers money. When the space shuttle Columbia disintegrated upon reentering Earth’s atmosphere, he provided the leadership necessary to move the agency through the tragedy. Under President George W. Bush, he worked to realize the administration’s ambitious vision for space exploration. He guided the agency through some tough times.

Years after he retired from NASA, in August of 2010, fate would bring O’Keefe about 10 miles northwest of Aleknagik, flying in a small seaplane.

The plane went down. Five of the nine passengers on board died, including [former Alaska] Senator [Ted] Stevens. Also on board was [NASA’s] current Deputy Administrator James Morhard.

DEPUTY ADMINISTRATOR JAMES MORHARD

I had formed a law firm with Ted Stevens, who was the chairman of the appropriations committee when I was his chief of staff, and a gentleman by the name of Bill Phillips and we ended up, in August, going fishing in Alaska. We were in a remote lodge — we were just there as friends — and the weather was bad.

Bill Phillips and I had decided, in the morning, to go fishing in front of the lodge with a guide. Came in for lunch and the pilot came out and said the weather had gotten better and do you all want to go to a river called the Nushagak River. So, nine of us including the pilot piled into this plane.

And normally I’d be always looking out the window to look for wildlife and, in this case, we just went right into the clouds. And, 15 minutes later, I remember feeling the impact just for a split second before I got knocked out.

And, I woke up on top of Sean O’Keefe. The seats had been rated for 20 Gs and all of them were sheared off except for the one Sean was sitting in. And so, there were bodies and metal just piled up in the front of the plane.

The folks that had passed, passed immediately.

NARRATOR

When the flight didn’t return as scheduled, pilots were scrambled for an aerial search. They located the wreckage in rugged terrain on the side of a mountain, but rescue efforts were hampered by poor weather. Survivors, including O’Keefe and his son, as well as Deputy Administrator Morhard, had to wait 12 hours for rescue.

The ELT that would have quickly notified the search and rescue network of the accident separated from its antenna during impact, disabling the signal and leaving the passengers lost in the wilderness.

Search and rescue professionals have long worried over the performance of ELTs. While the technology behind the devices is sound, they often don’t perform as they should in real-world situations.

A study prepared for NASA summarized ELT performance after a thorough review of thousands of aviation crash reports of the 1970s and 1980s. Some key takeaways from the study include high rates of non-activation, false alarm and the loss of 58 human lives per year due to ELT system and/or installation failure. These results were generally attributed to environmental factors, crash sensor reliability and a lack of an effective inspection and maintenance program.

After the harrowing crash of former Administrator O’Keefe’s plane, the SAR office, utilizing existing aeronautics expertise within the agency, underwent a comprehensive study of ELTs, hoping to improve their reliability and effectiveness.

Search and Rescue Mission Manager Lisa Mazzuca:

LISA MAZZUCA

NASA is here to always try to do better. And we certainly knew that with 20-, 30-year-old technology, that we could do better. In the case of ELTs, we knew that there were vulnerabilities in the system that were not allowing the beacon to transmit as much as it should upon a crash, thus not telling you where the aircraft is.

NARRATOR

At the culmination of this study in 2015, they conducted three controlled airplane crashes at NASA’s Langley Research Center’s Landing and Impact Research Facility, the same facility used to simulate splashdown for the Apollo capsule.

Based on their research, NASA developed recommendations for the Federal Aviation Administration and beacon manufacturers to improve ELT survivability.

Yearly, members of the SAR office attend the Experimental Aircraft Association’s AirVenture, the world’s largest fly-in airshow. There they share the lessons they’ve learned with the public. Beyond recommendations passed to beacon manufactures that improve the technology inside ELTs, they found many issues in installation that could lead to failure.

Since installation is usually the responsibility of a plane’s owner, this type of outreach is important to the aviation community. Many recreational pilots may not have the information they need to properly install their beacons. Oftentimes, small changes to their installation can vastly improve the performance of their ELTs.

These small changes could save their lives.

For example, adding an inexpensive fire sleeve can add minutes of transmission time in the event that a fire breaks out during a crash. Adding a little slack or small relief loops to the cabling can prevent it from pulling out at its socket. Making sure that the cable doesn’t cross the production breaks in the plane can prevent it from snapping should the plane crumple. Making sure that the ELT and antenna are properly affixed to the plane is paramount to the effectiveness of the system.

By following these guidelines, aviators can be confident that their ELT is prepared for the worst.

It might just save their lives.

While the original Cospas-Sarsat system has served aviators, sailors and adventurers well for many years, in the past decade, the international community began to want quicker response times and more accurate location data than the system of low-Earth-orbiting and geostationary instruments could accommodate.

NASA rose to the challenge.

The first upgrades to the system involved the flight elements of the network. New spacecraft in the global navigation satellite system, or GNSS, the international collection of navigation constellations like GPS, now carry NASA-developed search and rescue technology on board. These satellites in medium-Earth orbit can see larger swathes of the Earth than instruments on low-Earth orbit satellites, allowing faster beacon detection.

Additionally, the number of GNSS satellites carrying search and rescue instruments allow for trilateration, a location method that is orders of magnitude more accurate than Doppler shift geolocation. Ultimately, there will be more search and rescue instruments in space than ever before, allowing for rapid, accurate location determination.

After Cospas-Sarsat implemented the medium-Earth orbit constellation, the SAR office began developing second-generation beacons that take full advantage of the new space segment. These beacons further improve the location accuracy and detection time of the system.

LISA MAZZUCA

The reason why we call them second-generation beacons is because this project is very old. This is an international program with 45 countries, but this began in 1979. And so, back then, we had the beacons that we are still using now, pretty much — that are still commercially available — with very little modification to the beacon technology.

And, again: NASA is here to try to make sure that we’re staying on top of technology capability and to get it infused into every element of search and rescue. And, in this case, it’s about the beacon.

NARRATOR

To decrease response times for first-responders, second-generation beacons front-load their distress signals. First-generation beacons send a signal regularly upon activation. Second-generation beacons will incorporate intelligent transmit scheduling, sending more signals in the crucial minutes after activation and then reducing the number of signals as time goes on.

Additionally, first-generation beacons send all the information on the beacon every time they contact the satellite. To use their battery power more efficiently and extend the life of the beacon after activation, second-generation beacons separate that information into a primary field, which contains all the beacons’ embedded identification information, and multiple rotating fields with different functions.

Finally, the second-generation beacons are covert. First-generation beacons “scream” at 406 MHz. This makes them easy to find, but more susceptible to interference. Second-generation beacons send spread-spectrum transmissions, which makes them less prone to interference and open to broader applications.

In response to recent aviation disasters, the international community has requested that a global, real-time tracking system be implemented by 2021. Recommending their second-generation beacon technology as a solution, NASA’s SAR office is developing a new aviation distress-tracking system.

This innovation, dubbed Emergency Locator Transmitter-Distress Tracking, will use data from aircraft avionics to determine when a plane is in distress before a crash. After activation, the system will send “breadcrumbs,” or location points, through the Cospas-Sarsat satellite network as it descends. Adopting this technology will help first responders locate a wreckage faster, improving their ability to assist survivors and gather important data about what caused the incident.

The SAR office is also developing a new direction-finding receiver that can home in on the frequency of their second generation beacons. Using this device, NASA is studying the use of unmanned aerial systems equipped with these receivers in water-based search and rescue efforts for the U.S. Coast Guard.

The unmanned aerial vehicles are fitted with the new location homing/direction finding receivers to guide them to an activated beacon. The unmanned aerial vehicle can then notify search and rescue forces of the precise location of the incident and may even be able to drop flotation devices. Implementing this technology will reduce the risk to first responders undertaking difficult or dangerous rescue missions and improve response times, resulting in more lives saved.

In addition to the second-generation beacon technology, which has been passed to commercial industry for manufacture and sale, the SAR office has applied the technology to beacons that will aid NASA in locating astronauts after splashdown and egress from the Orion capsule. These beacons, Advanced Next-Generation Emergency Locator, or ANGEL beacons, are further miniaturized second-generation beacons placed on astronaut life vests.

NASA survival systems engineer Cody Kelly:

CODY KELLY

Normally, when our astronauts land, they’re picked up by the Exploration Ground Systems, which is partnered with the Navy and the Air Force, Department of Defense human spaceflight support Detachment 3 at Patrick Air Force Base. They’ll actually take the capsule and pull it into the well deck of a ship and the astronauts will be removed by military and NASA personnel and taken directly to medical care if needed.

On that absolute worst day, where the crew had to get out on their own, they would open up the side hatch of the Orion capsule — much like the Apollo capsule — and then deploy all of our different survival equipment — like a life raft, user life preservers — and actually jump out of the capsule and swim to the life raft.

We’ve modeled everything a lot like we do for spacewalks, so that the crew is always tethered to the vehicle and to their survival equipment — because we know the ocean is such a dynamic and dangerous place. And then they would get in their life raft, turn on their ANGEL beacon and our worldwide rescue forces would come and pick them up.

NARRATOR

They’re the beacons I described earlier — the ones lost somewhere in the dénouement of the Artemis missions. It is an integral piece of the picture, but so small it might be overlooked.

As a writer at NASA, I often feel like I’m searching for missions outside the spotlight — invisible in the dark.

Often, the things I find don’t belong at, or near the climax. They’re at the bottom of Freytag’s pyramid. They’re the odd, unknown impacts that small projects at NASA end up having on the world at large. They might not be big or shiny like a rocket or have the beautiful hues of a new portrait of the cosmos taken by a telescope. Instead, they could be a tiny microchip — one that fits in the palm of your hand. A technology built by NASA, but passed on to commercial enterprise and the world at large.

They’re innovations that might — from Artemis to Aleknagik — save a life.

This season of “The Invisible Network” debuted in November of 2019. The podcast is produced by the Space Communications and Navigation program, or SCaN, out of Goddard Space Flight Center in Greenbelt, Maryland. Episodes were written and recorded by me, Danny Baird, with editorial support from Matthew Peters. Our public affairs officers are Peter Jacobs of Goddard’s Office of Communications, Clare Skelly of the Space Technology Mission Directorate and Kathryn Hambleton of the Human Exploration and Operations Mission Directorate.

Special thanks to Barbara Adde, SCaN Policy and Strategic Communications director, Rob Garner, Goddard Web Team lead, Amber Jacobson, communications lead for SCaN at Goddard, and all those who have lent their time, talent and expertise to making “The Invisible Network” a reality. Be sure to rate, review and subscribe to the show wherever you get your podcasts. For transcripts of the episodes, visit NASA.gov/invisible. To learn more about the vital role that space communications plays in NASA’s mission, visit NASA.gov/SCaN.