Today, May 22, SpaceX successfully launched five Iridium NEXT satellites and a pair of NASA gravity measurement satellites into orbit. The launch took place at 3:47 p.m. ET from Space Launch Complex 4E at Vandenberg Air Force Base, California.
It is the sixth launch of eight planned by SpaceX for Iridium to put up a new Iridium NEXT constellation with a total of 75 new satellites in orbit, 66 for the operational constellation and nine on-orbit spares. The Iridium NEXT constellation is the company’s new and improved second-generation, replacing the original 95 Iridium satellites launched between 1997 and 2002.
Iridium, like many pioneers, was ahead of its time, using a network constellation of low flying satellites in different orbits (planes) to deliver voice and low-speed data on a truly global basis. The company filed for bankruptcy and was close to shutting down the entire network before it successfully reorganized in 2001 with the U.S. Department of Defense as an anchor customer.
The second generation Iridium NEXT satellites are designed to deliver L-band data speeds of at around 350 Kbps at launch and ramp up to 1.4 Mbps. Iridium NEXT satellites also carry one or two hosted payloads. All carry ADS-B receivers for tracking aircraft, with service available through Aireon, a joint venture of Iridium and several national aviation bureaus. Most — 58 –carry an AIS payload to track maritime traffic for Canada-based exactEarth.
Internet of Things (IoT) service are expected to significantly benefit from the Iridium NEXT upgrade, with more available bandwidth opening up more detailed monitoring capabilities and new applications. Since Iridium NEXT is in low Earth orbit (LEO) with the constellation of satellites a flying router network, it delivers voice and data with minimal latency to anywhere on the planet without the half-second (or more) delays introduced by higher-flying geosynchronous (GEO) satellites.
Not to be slighted, NASA’s GRACE-FO is a joint U.S./German mission to track the continuous movement of water and other changes in Earth’s mass on and beneath the planet’s surface. The twin spacecraft formation fly, measuring slight changes in distance apart as gravity changes due to water movement. Flying for 5 years, GRACE-FO will be able to track changes in underground water storage, soil moisture, ice sheets and glaciers, data applicable to ocean research, drought monitoring, flood potential, and agricultural impacts.
The Iridium-6/GRACE-FO launch is a rideshare mission brokered between Iridium and NASA. GRACE-FO was originally slotted to be launched in 2017 on a Ukrainian-built Dnepr rocket launched by Russia in 2017, but conflict between the two countries ended up shutting down the joint operational arrangement. Splitting the cost of launch with NASA and German, the country responsible for arranging launch services, allows Iridium the opportunity to put more satellites into orbit while saving some money.
Previous and future launches put 10 Iridium NEXT satellites into orbit per mission. Iridium expects to have two more launches by the end of the third quarter this year, putting another 20 satellites into orbit and completing the Iridium NEXT upgrade.
