Wrapping up its personal-best-beating 21st launch of the year—a 15% uplift on 2017’s achievement—SpaceX has triumphantly delivered the first member of the Global Positioning System (GPS) Block III constellation into Medium Earth Orbit (MEO). Flying only days after Spaceflight Industries’ SSO-A Smallsat Express and NASA’s CRS-16 Dragon, today’s mission marked only the third occasion in SpaceX history that as many as three Falcon 9s have roared aloft within a single calendar month.
All told, 2018 has been hugely successful for the Hawthorne, Calif.-headquartered launch services provider, which has boosted over a hundred discrete payloads into orbit, seen the maiden voyage of the mammoth Falcon Heavy and reflown a dozen Falcon 9 cores, one of which now has three launches to its name.
Primary payload for today’s flight was GPS IIIA-01, the first member of the next-generation GPS Block III constellation of global positioning, velocity and timing satellites, bound for Medium Earth Orbit (MEO). The Air Force awarded a $1.4 billion contract to Lockheed Martin in May 2008 to develop the Block III network, which is anticipated to eventually comprise as many as 32 satellites, launched through 2034. However, the program’s first launch has occurred more than four years later than planned, due to ongoing payload problems.
“Launch is always a monumental event, and especially so since this is the first GPS satellite of its generation launched on SpaceX’s first National Security Space mission. As more GPS III satellites join the constellation, it will bring better service at a lower cost to a technology that is now fully woven into the fabric of any modern civilization,” said Lt. Gen. John F. Thompson, commander of the Space and Missile Systems Center and Air Force program executive officer for Space. “It keeps GPS the gold standard for positioning, navigation, and timing information, giving assured access when and where it matters. This event was a capstone, but it doesn’t mean we’re done. We’re going to run a series of procedures for checkout and test to ensure everything on Vespucci functions as it was designed.”
With 500 times the transmitter power of current GPS systems, the Block III satellites will benefit from improved navigational warfare capabilities, with three times better accuracy and eight times better anti-jamming functionality, enabling them to shut off GPS services to limited geographical locations, whilst maintaining provision for U.S. and allied forces. GPS Block III features a cross-linked command and control architecture, which permits the entire constellation to be updated from a single ground station. Furthermore, the satellites will showcase a new spot-beam capability for enhanced military (‘M-code’) coverage and increased resistance to hostile jamming. These enhancements are expected to contribute to improved accuracy and assured availability for military and civilian users worldwide.
“More than four billion military, commercial and civilian users connect with signals generated by GPS satellites every day,” said Johnathon Caldwell, Lockheed Martin’s Vice President for Navigation Systems. “The launch of GPS III SV01 will be the first step in modernizing the Air Force’s GPS constellation with the most powerful and resilient GPS satellites ever designed and built.”
Based upon Lockheed Martin’s tried-and-true A2100 “bus”, which boasts a modular structure, capable of supplying 15 kilowatts of electrical power, via high-efficiency solar cells, radiation-cooled traveling-wave-tube assemblies and improved heat-pipe design, each GPS Block III weighs around 8,500 pounds (3,900 kg). The A2100’s 15-year operational life span represents a 25-percent quantum leap above the lifetime of the GPS IIF satellites currently in orbit. GPS IIIA-01 was fabricated at Lockheed Martin’s advanced GPS III Processing Facility (GPF) near Denver, Colo., with the spacecraft’s propulsion core—its structural and power-providing “backbone”—on site for assembly, integration and testing by September 2012.
Meanwhile, GPS IIIA-01’s system module was “powered-up” for the first time in February 2013 to demonstrate its mechanical interfaces, ahead of electrical and integrated hardware-software trials. Navigation, communication and hosted-payload antenna assemblies were delivered in mid-2013 and the system module and propulsion core were finally integrated as a complete spacecraft for testing in early 2015.
However, GPS Block III has suffered from a range of developmental issues, including problematic ceramic capacitors, electromagnetic interference between payload components and delays in bringing the constellation’s state-of-the-art Operational Ground Segment fully online. Finally, in September 2017 the Air Force declared GPS IIIA-01 as “Available for Launch” (AFL) and the satellite underwent end-to-end remote connectivity testing, before being placed into storage to await a flight slot. Last June, it was formally called up for launch and in late August 2018 was shipped via C-17 Globemaster III aircraft from Buckley Air Force Base, Colo., to Cape Canaveral Air Force Station, where it then underwent pre-flight processing and fueling at Astrotech Space Operations in Titusville.
By this time, GPS IIIA-01 had also received the official nickname of “Vespucci”, in honor of the 15th-century Italian explorer, navigator and cartographer Amerigo Vespucci. Earlier this month, the satellite was encapsulated in its bulbous payload fairing, ahead of integration with the Upgraded Falcon 9.
As such, SpaceX would loft the first member of the GPS Block III network, having received an $82 million launch services contract in April 2016. In readiness for launch, the Upgraded Falcon 9—featuring a Block 5 core, designated “B1054” and previously unflown—was erected at Space Launch Complex (SLC)-40 at the Cape and completed a smooth Static Fire Test of its nine Merlin 1D+ first-stage engines on 14 December. The booster was returned to the horizontal integration facility for the payload fairing and was then returned to the pad. It was confirmed vertical on SLC-40 in imagery provided by AmericaSpace’s Jeff Seibert as night fell on Monday, 17 December.
Weather conditions for Tuesday’s opening launch attempt—during a 24-minute “window” from 9:11 a.m. through 9:35 a.m. EST—were highly favorable, with a 90-percent likelihood of acceptable conditions, according to the 45th Weather Squadron at Patrick Air Force Base. The primary weather concern centered upon a possible violation of the Thick Cloud Rule, although the optimistic outlook was expected to deteriorate slightly to around 80-percent-favorable in the event of a 24-hour scrub to Wednesday.
In attendance for the opening launch attempt was Vice President Mike Pence, who chairs the National Space Council. Notwithstanding the positive meteorological outlook, upper-level winds were classified as “No-Go” and T-0 was realigned for 9:34 a.m. EST, close to the end of Tuesday’s window, which had by now been extended slightly to close at 9:37 a.m. Fueling of the Upgraded Falcon 9 with liquid oxygen and a highly refined form of rocket-grade kerosene (known as “RP-1”) got underway shortly before 9 a.m. However, a “Hold” condition was declared at T-7 minutes and, as the window approached its closure, Tuesday’s attempt was scrubbed. Launch teams were instructed to recycle for a second attempt at 9:07 a.m. EST Wednesday, 19 December.
SpaceX later identified the reason for the scrub as “an out-of-family reading on first-stage sensors”, which obliged an additional delay from Wednesday until 9:03 a.m. EST Thursday. Unfortunately, Thursday’s weather outlook was only 20-percent-favorable, with forecasters highlighting the action of a developing high-pressure system along the Gulf Coast, which was predicted to bring severe thunderstorms, very high winds and even hail or tornado-like conditions. It was noted that conditions would improve marginally to 40-percent-favorable on Friday, before brightening to 80-percent-favorable on Saturday. Unsurprisingly, Thursday’s attempt was scrubbed before the onset of fueling, so horrendous was the weather outlook, and a 48-hour turnaround was declared. However, Saturday’s attempt—pushed until near the end of the window, due to strong upper-level winds—ultimately came to nothing and SpaceX again recycled 24 hours to Sunday.
In advance of Sunday’s attempt, which opened at 8:51 a.m. EST, SpaceX noted that due to payload mass and energy requirements needed to loft GPS IIIA-01, the B1054 core would not be recovered—either at Landing Zone (LZ)-1 at the Cape or offshore on the Autonomous Spaceport Drone Ship (ASDS)—and, as such, was not equipped with hypersonic grid-fins or landing legs. Launch occurred on time at the opening of Saturday’s window and the Upgraded Falcon 9 speared perfectly into a crystal-blue Florida sky. A little under three minutes into the flight, the first stage burned out and separated, whereupon the single Merlin 1D+ Vacuum second-stage engine ignited for 5.5 minutes to deliver the heavyweight payload into orbit. It shut down a little over eight minutes after departing the Cape and the stack coasted for an hour, ahead of a second “burn”, and deployment of GPS IIIA-01 at just under two hours into the flight.
“In the coming days, GPS III SV01 will use its liquid apogee engines to climb into its operational orbit about 12,550 miles above the earth. We will then send it commands to deploy its solar arrays and antennas, and begin on-orbit checkout and tests, including extensive signals testing with our advanced navigation payload provided by Harris Corporation,” said Johnathon Caldwell, Lockheed Martin’s Vice President for Navigation Systems.
“We are excited to begin on-orbit test and demonstrate its capabilities,” Caldwell added. “By this time next year, we expect to also have a second GPS III on orbit and users should be receiving signals from this first satellite.”
Current plans call for the remaining nine members of GPS Block IIIA to be AFL by around 2022, whereupon the focus will shift towards the delivery of 22 uprated GPS Block IIIF “follow-on” satellites between 2026-2034. These satellites are expected to demonstrate several advanced systems, anchored by four Technology Insertion Points, including on-orbit reprogrammable digital payloads, high-power amplifiers and near-real-time commanding. Last September, the Air Force awarded Lockheed Martin a $7.2 billion contract to build the Block IIIF network.