The NBC News article Next-generation satellites gave federal officials key data in Boeing 737 Max investigation says:
The Federal Aviation Administration, or FAA, grounded Boeing's 737 Max airplanes on Wednesday, after receiving data from air traffic surveillance company Aireon about the deadly crash of Ethiopian Airlines Flight 302.
Aireon's system piggybacks on Iridium's network of 75 satellites. Expected to become fully operational in a few weeks, Aireon can track airplanes anywhere on the planet. But the company's data is already proving to be critical, as Aireon said in a statement to CNBC that "the system was able to capture information associated with Flight 302."
While Aireon declined to make company officials available for an interview while the investigation is ongoing, the company said it is working with federal officials to provide them with raw data. Even though the Aireon system has not been fully rolled out, the company is able to provide investigators with information about an aircraft's location, velocity, altitude and more.
Since the Aireon systems are physically attached to the Iridium Next satellites, they share the same orbit and attitude control, and most likely power and some other bus functions as well like thermal management.
But do the Aireon systems use Iridium systems to communicate to the ground, or do they make their own contact with their own ground stations?
I wonder if being attached to a data communications and IoT-like service-providing satellite, the Aireon systems could just use Iridium's data messaging service directly?