(CNN) On the fifth anniversary of the disappearance of Malaysia Airlines Flight 370 , the aviation industry is on the verge of implementing technology that would make a similar tragedy impossible.

It's hard to believe that we still don't know exactly what happened to the Boeing 777, or why it vanished en route from Kuala Lumpur to Beijing on March 8, 2014.

The idea that an airliner carrying 239 passengers and crew members could simply disappear was unthinkable — even for veteran aviation industry authorities like Miguel Marin, the chief of operational safety at the Air Navigation Bureau, which is part of the International Civil Aviation Organization. (The ICAO, a United Nations agency, sets worldwide aviation standards.)

"It was inconceivable that in this day and age we would lose an airplane that big without a trace," Marin told CNN on the phone from ICAO's Montreal headquarters. The tragedy shocked the ICAO enough that it quickly got to work.

The result is a long-term plan called the Global Aeronautical Distress and Safety System (GADSS), which uses innovations in technology and communications to better watch the planes we fly on. One part of the plan requires that all large aircraft now automatically track their flight positions every 15 minutes, while another new rule focuses on what happens when a commercial flight is in distress.

You may remember that the reason the world lost track of MH370 was because its transponders mysteriously stopped transmitting the airliner's location about three minutes after the jet's final radio call. Now the ICAO is mandating that the world's airlines provide a so-called "distress tracking system" on their planes by 2021.

The system would autonomously transmit an aircraft's position at one-minute intervals whenever the plane is in "a position that — if it is left unattended — will result in an accident," according to Marin. This system can work "irrespective of any pilot action," Marin added; transponders could transmit a distressed plane's position and unique aircraft ID to authorities, who could launch a rescue.

While some pilots have opposed the idea as a safety issue, saying they want to be able to turn off any electrical system on board in case of a fire or other in-flight emergency, a company called Aireon says customers -- including Malaysia Airlines -- are already signing up for its system, which it plans to have on line by next month.

The company uses a constellation of 66 interconnected satellites that will make it possible to monitor all air traffic in real time — even over vast stretches of ocean where ground-based radar coverage is impossible.

Space-based global tracking

Here's how it works: Planes are outfitted with devices called transponders, which send signals that are picked up by ground stations and the orbiting satellites. Those signals are then transmitted to airlines and air traffic controllers.

"This will be the first time ever that all aircraft are being tracked around the world in real time," said Don Thoma, the CEO of Aireon, which owns the technology. "As you talk to other people in the industry, they really view this as a kind of fundamental, game-changing addition to the air traffic control and aviation infrastructure."

Space-based global tracking is expected to eliminate the vast blind spots in aircraft tracking that still exist over the world's oceans, deserts, mountains and other remote regions. These are the gaps that resulted in the loss of MH370 and created lingering questions about its fate.

Investigators were able to get clues to the jet's location from its smart-tech engines, which were programmed to regularly ping maintenance data to orbiting satellites. But the pings weren't designed for tracking, and they could only reveal that MH370's last position was believed to be somewhere in the southern Indian Ocean

This lack of information drove the creation of the ICAO's plan, Marin said: "The standard for aircraft tracking would not have happened otherwise."

Now, Marin says he's confident that the "ICAO has implemented and adopted the standards that would prevent an accident such as Malaysia 370 from happening ever again."

Searches and disappointment

The years since the disappearance of MH370 have been difficult for loved ones of the passengers and the crew. No crash site has been discovered, and bodies have not been found. Memorial services were held without any certainty about what happened.

Photos: Remembering the passengers of MH370 There is still no way to know for sure why Flight MH370 ended, but we are learning more about the lives of those on board. CNN is remembering them through snapshots shared with us. Hide Caption 1 of 12 Photos: Remembering the passengers of MH370 Rodney and Mary Burrows were looking forward to becoming first-time grandparents after their return home to Australia. Hide Caption 2 of 12 Photos: Remembering the passengers of MH370 Australians Catherine and Robert Lawton were traveling with friends on vacation when the flight disappeared. Hide Caption 3 of 12 Photos: Remembering the passengers of MH370 Paul Weeks was traveling to Mongolia for a new job as an engineer. His wife says Paul left behind his watch and his wedding ring before the trip, in case anything happened to him while he was away. Anderson spoke with Paul's brother & sister who said they are coping by spending time together as a family. Hide Caption 4 of 12 Photos: Remembering the passengers of MH370 Chandrika Sharma, left, was on Flight 370; her daughter Meghna and husband K.S. Narendran wait patiently, trying to manage their anxiety and longing for her return. Hide Caption 5 of 12 Photos: Remembering the passengers of MH370 Muktesh Mukherjee and Xiaomo Bai had been vacationing in Vietnam and were on their way home to their two young sons in Beijing. Hide Caption 6 of 12 Photos: Remembering the passengers of MH370 76-year-old Liu Rusheng, an accomplished calligrapher and one of the oldest passengers on the flight, was in Malaysia to attend an art exhibition with his wife. Hide Caption 7 of 12 Photos: Remembering the passengers of MH370 Teens Hadrien Wattrelos and Zhao Yan are shown in a photo on Wattrelos' Facebook page. The photo is captioned, simply, "I love you," in French. Hide Caption 8 of 12 Photos: Remembering the passengers of MH370 Firman Chandra Siregar, 24, studied electrical engineering in Indonesia and was on his way to Beijing on board Flight 370 to start a new job at an oil company. Hide Caption 9 of 12 Photos: Remembering the passengers of MH370 Patrick Francis Gomes, center, was the in-flight supervisor for the missing plane. His daughter describes him as a quiet person with a sense of humor. Hide Caption 10 of 12 Photos: Remembering the passengers of MH370 Ch'ng Mei Ling, a Malaysian citizen who lives in Pennsylvania, is a process engineer at a chemical company. Hide Caption 11 of 12 Photos: Remembering the passengers of MH370 We do not have photos of all 239 passengers, but we wanted to remember that there are loved ones around the world missing them right now. View CNN's complete coverage of Flight 370. Hide Caption 12 of 12

In January 2015, nearly a year after the plane disappeared, Malaysia's government officially declared the missing plane an "accident" and said all on board the aircraft were presumed dead.

But two searches of the Indian Ocean continued until 2018, costing tens of millions of dollars. In 2015 and 2016 debris that was confirmed to be from MH370 — including a wing fragment and part of the jet's flaperon — washed ashore in eastern Africa and nearby islands, thousands of miles from the region where the plane vanished.

MH370's flaperon was found in eastern Africa.

Officials with the Australian Transport Safety Bureau told an Australian parliamentary hearing last year that the plane had likely crashed into the Indian Ocean after running out of fuel.

Marin, who agrees MH370 likely crashed, believes that if it had been equipped with a distress tracking system it would have automatically alerted authorities and pinpointed the location of the plane's wreckage — solving one of the biggest lingering questions in this historic mystery.

The biggest challenge now is creating a "one-stop" data repository where air traffic controllers, search and rescue coordinating centers and aviation regulators such as the FAA can all get access.

Marin said he's confident the ICAO will have a prototype distress tracking system repository that will be operational and ready for testing in a year's time, with the goal of having it in place and fully operational worldwide by January 2021, Marin said.

Space-based tracking also saves time, money and cuts pollution

"The whole reason Aireon was put together was certainly to help improve safety, but it also provides a significant benefit to the airlines," Thoma said. "The fact that you know what's happening — where the aircraft are — allows airlines that fly over oceans to operate more efficiently."

More than 1,500 daily flights connect the United States and Europe. With real-time surveillance, pilots and air traffic controllers will have much more flexibility to optimize flight paths, cut flying time, burn less fuel, and emit less greenhouse gas — "all very important things to the aviation industry and to passengers," Thoma said.

Aireon, along with Canadian and UK aviation authorities, plan to start live tests in parts of Canada and across the North Atlantic in April.

The US Federal Aviation Administration has also been involved in the design, testing and development of Aireon's tracking system, Thoma said, and the organization plans to start testing it at the end of next year. "We're hoping at that point they'll expand it to the full oceanic use."

We may never know all the answers to what happened to MH370, but if space-based tracking and ICAO's plan prove successful, it's unlikely we'll ever see another tragedy quite like it again.