WRAL WeatherCenter Blog

Satellite net aims to prevent another loss like MH370

Posted January 17

Aircraft positions tracked by satellite help eliminate gaps over oceans and other areas lacking ground-based receivers (Credit: Aireon LLC)

After nearly three years, authorities announced their decision to suspend the underwater search for Malaysia Airlines flight 370 (MH370). The Boeing 777 aircraft with 239 people on board vanished from tracking systems on March 8, 2014.

The disappearance of MH370 and Air France flight 447 in 2009 prompted the United Nations’ International Civil Aviation Organization (ICAO) to develop the Global Aeronautical Distress and Safety System (GADSS). Manual tracking every 15 minutes is currently required of aircraft with more than 19 passengers. Automated GADSS tracking is required by November 2018.

While there was some contact with MH370 via the INMARSAT satellite network for an additional 7 hours, data was limited, providing no specifics about the plane's flight path. Detailed positional information transmitted by aircraft via automatic dependent surveillance–broadcast (ADS-B) is currently limited by line of sight to receivers on the ground. Those receivers can’t be placed in rugged terrain or the vast deserts and oceans that lie beneath about 70 percent of global airspace. Until now.

A system designed to meet GADSS requirements launched, largely unnoticed, aboard SpaceX’s return to flight on Saturday, Jan. 14. Piggybacked aboard each of the 10 Iridium NEXT satellites successfully launched into polar orbit from Vandenberg Air Force Base in Calif., is a payload from Aireon LLC. The McLean, Va., company is a joint venture between civil aviation bodies in Canada, Italy, Ireland and Denmark and Iridi created to implement a space-based ADS-B system.

"This successful first launch brings us one step closer to changing the way the world flies by enabling the ability to track aircraft anywhere on the planet,” said Aireon CEO Don Thoma.

SpaceX launch

The low-Earth orbit of the satellites enables aircraft signals to be transmitted into space without additional equipment or changes to the existing aircraft avionics. The satellites link with each other to pass information on to air traffic control to help ensure aircraft are sufficiently separated in the air and on the ground. In addition to meeting GADSS requirements, the company estimates millions in fuel savings for airlines through flight-path optimization.

Global coverage is planned by 2018 as Iridium and SpaceX replace the original 72 satellite Iridium constellation in seven launches over the next 18 months. Qatar Airways, with much of its route map over the Atlantic and Indian Oceans as well as remote deserts in Africa, is Aireon's first customer.

Iridium is eager to replace its aging first generation network. Ten satellites have been lost since 2001 – nine from in-orbit failures and one when Iridium 33 collided with an inactive Russian military satellite in 2009. The Defense Department's Space Surveillance Network and NASA's Orbital Debris Program Office continue to track hundreds of pieces of debris from that incident for threat to U.S. and other satellites. About a third of that debris remains in orbit according to NASA estimates.

iridium flare

You can spot Iridium satellites

Iridium satellites can be seen with the naked eye, if you know where and when to look. Unlike the international Space Station which appears as a point of light moving steadily across the sky, Iridium satellites flare becoming bright, often very bright, for a few seconds as they rotate.

With clouds expected to begin breaking during the day Wednesday, the next opportunity to see an Iridium flare is Thursday at 5:44 pm. Look up, nearly overhead and just to the north east. At 17:44, Iridium 34 will become brighter than Venus and then fade away over a few seconds. The Heavens Above website provides additional predictions for Iridium flares.

Tony Rice is a volunteer in the NASA/JPL Solar System Ambassador program and software engineer at Cisco Systems. You can follow him on twitter @rtphokie.


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