Future provider of space-based ADS-B air traffic management (ATM) surveillance services Aireon will see its aircraft positional-data collection and validation capabilities go up by an order of magnitude in November as a result of the successful October 9 launch from Vandenberg Air Force Base of a SpaceX Facon 9 booster ferrying to low-earth orbit 10 Iridium NEXT communications satellites.
Each of the 10 NEXT satellites, as well as 20 already in orbit and 45 more scheduled for orbit over the next 10 months, carries an automatic dependent surveillance-broadcast (ADS-B) transceiver developed by Aireon and Harris Corporation for Aireon to use to capture ADS-B positional signals from space, allowing it to circumvent the 250-mile-range line-of-sight restriction to which ground-based ADS-B receivers are subject. In this manner, Aireon expects its space-based ADS-B service to offer active ATM surveillance of all ADS-B-equipped aircraft wherever they fly in the world, including remote areas of oceanic and territorial airspace in which procedural ATM control is now required because of the line-of-sight restriction affecting ground-based ADS-B and radar systems.
During November, assisted by customers Nav Canada, Enav, Naviair, the Irish Aviation Authority (IAA) and South Africa’s Air Traffic and Navigation Services (ATNS), all of which now have the server-and-terminal equipment installed that allows them to receive feeds of Aireon's ATM surveillance data (as does the UK’s NATS), Aireon will take over control from Iridium the space-based ADS-B payloads on the 10 newly orbited satellites. By then Iridium will have completed its initial evaluation of the performance of the 10 newly orbited NEXT satellites.
The payloads on the 10 additional satellites will increase to 23 the number of operational orbiting space-based ADS-B payloads collecting and re-transmitting data to Aireon, via its ground station on the far-north island of Svalbard. Aireon doesn't yet control seven satellites orbited in the first two launches of NEXT satellites, because Iridium is intentionally drifting the seven satellites into different orbital planes, according to Vincent Capezutto, Aireon’s chief technology officer and v-p of engineering.
Iridium and Space X plan a further five Falcon 9 launches—putting into orbit 45 more NEXT satellites to complete the constellation of operational orbiting satellites plus spares—at intervals of approximately two months from October 9. Assuming they achieve that schedule, Aireon should take full operational control of all of its orbiting payloads by September 2018, allowing it and major customers such as Nav Canada to begin testing space-based ADS-B for live, everyday ATM surveillance by the beginning of 2019, Capezutto estimated.
On October 9 SpaceX launched a Falcon 9 booster carrying 10 Iridium NEXT communications satellites and their accompanying Aireon space-based ADS-B transceiver payloads for air traffic management surveillance use into its planned low-earth orbit. The booster then deployed all 10 satellites into their planned orbital positions.
The launch, which is the third of eight planned Falcon 9 launches performed to ferry 75 NEXT satellites in all into orbit, took place at 5:37 a.m. local time at Vandenberg Air Force Base in California. Allowed only a one-second window of delay before it would otherwise have been postponed, the launch happened precisely on time. The satellite-dispenser ring on the booster’s second stage deployed the 10th NEXT satellite into its planned orbit 1 hour, 12 minutes and 14 seconds after the booster launched.
SpaceX characterized as “nominal” all the performance targets for the launch. The targets achieved included the successful landing of the reusable Stage 1 main booster stage on SpaceX’s drone landing ship, located in the Pacific Ocean some 300 kilometers (160 nautical miles) down-range.
Capezzuto told AIN that all 10 satellites orbited in the third launch deployed into number four of the six orbital planes that the six rings the NEXT constellation will occupy. Each ring will contain 11 operational satellites as well as either one or two orbiting spares, three rings—in the NEXT orbital planes numbers 2, 3 and 6—each being given two orbiting spares and the rings in orbital planes 1, 4 and 5 each being given one.
Capezutto said the first launch carrying 10 NEXT satellites, on January 14, placed eight satellites into orbital plane 6 as well as two that Iridium is drifting into the adjacent plane 5. The second launch, on June 25, put five NEXT satellites into plane 3 plus one being drifted to plane 4 and four to plane 2.
Iridium expects SpaceX to perform at intervals of approximately two months the next five launches of Iridium NEXT satellites with Aireon space-based ADS-B payloads. Four launches will have 10 satellites and one will have five, launch number eight being a “ride share” with satellites for NASA's Gravity Recovery and Climate Experiment (GRACE) mission.
The company plans for launch four to put eight satellites into NEXT orbital plane number 2, plus two that it will drift to plane 1. Launch five will orbit 10 satellites into plane 1. Launch six will orbit 10 into NEXT orbital plane 5. Launch seven will place eight into plane number 3 plus one for drifting to plane 2 and one to plane 4. Launch eight will place five NEXT satellites into plane 6.
SpaceX’s October 9 launch will give Aireon a total of 23 operational space-based ADS-B payloads. (The payloads on seven satellites now being drifted to new orbits aren’t available to Aireon yet.) By late August, the 13 payloads then available to Aireon had generated more than 6 billion ADS-B position reports at an average position-update rate of five seconds.