No Trick – all Treat: ULA conducts third October flight with GPS IIF-11 launch
CAPE CANAVERAL, Fla — No ghouls, demons or even ground support gremlins stopped United Launch Alliance (ULA) from sending the 11th Block IIF GPS satellite to orbit on Saturday, Oct. 31. Using the 401 configuration of the venerable Atlas V booster, the Colorado-based company got the third mission of the month underway – at 12:13 p.m. EDT (16:13 GMT).
The launch had been scheduled to take place on Friday, Oct. 30, but a leak in ground support equipment was discovered requiring a 24-hour delay. This meant the mission would be the third flight of an Atlas V for the month of October, and that it would fall on the U.S. holiday – Halloween. ULA issued a statement about the delay which included the following:
“[…] on Thursday, during final launch preparations a leak was discovered in a ground support equipment valve for the launch pad water suppression system. The valve was replaced and verification tests were successfully completed.”
The Atlas V booster delivered the eleventh IIF GPS satellite into a semi-synchronous circular orbit. The mission got underway from Cape Canaveral Air Force Station’s Space Launch Complex 41 located in Florida.
“Today’s flight will be on an Atlas V 401 configuration, which means it has a four-meter payload fairing and no solids as well as a single engine in its upper stage,” Victoria Porto, with ULA and the U.S. Air Force told SpaceFlight Insider. “Today’s flight was the 11th of 12 planned satellites, with the 12th set to launch in February.”
More formally known as a part of the Navstar Global Positioning System (GPS), GPS IIF-11 will be part of a constellation of satellites that will provide navigation services to both military and civilian users. This fleet of spacecraft is managed by the 50th Space Wing, based out of Schriever Air Force Base, in Colorado.
The fleet is comprised of some 24 satellites, which are positioned in six different planes. Each plane will contain a minimum of four satellites which are, in turn, placed in orbit some 11,000 nautical miles (20,372 kilometers) above our world.
These spacecraft are perpetually busy, utilizing atomic clocks to constantly transmitting digital radio signals which denote their exact location – and precise time. The Block IIF GPS satellites have a planned design life of 12 years.
ULA has detailed just how precise the transmissions from these satellites are via a booklet issued by the company: “With the proper equipment, users can receive these signals to calculate time, location, and velocity. The signals are so accurate that time can be measured to within a millionth of a second, velocity within a fraction of a mile per hour, and location to within feet.”
GPS technology has proliferated in the past couple decades, having been developed for use on aircraft, ocean-going vessels, land vehicles, as well as personal devices including smartphones. With all the extra requirements that have been placed on the constellation, the United States Air Force decided to grant the constellation with the following capabilities to both sustain the fleet – while allowing it to be capable of increased performance:
– Two times greater predicted signal accuracy than heritage satellites.
– New L5 signals for more robust civil and commercial aviation.
– An on-orbit, reprogrammable processor, receiving software uploads for improved system operation.
– Military signal “M-code” and variable power for better resistance to jamming hostile environments, meeting the needs of emerging doctrines of navigation warfare (provided by United Launch Alliance).
At roughly 2.7 seconds before liftoff, the rocket’s sole RD-180 engine was activated. It burned for approximately 3.8 seconds before the booster and its precious cargo left the launch pad.
The Atlas V 401 utilizes none of the Aerojet Rocketdyne AJ-60A solid rocket boosters that are employed on other missions. This meant that this morning’s flight was a rather languid affair, with the booster slowly marching across the partly-cloudy Florida skies. Weather could not have been much better with a negligible breeze and a 90 percent chance of favorable conditions for launch.
Almost 17-and-a-half seconds into the flight, the Atlas V booster carried out a roll / pitch / yaw maneuver to place it on the correct trajectory.
It took the Atlas V about a minute and 18 seconds before it was traveling at Mach 1. The booster entered into the region of the atmosphere known as maximum dynamic pressure or max-Q at about a minute and a half into the mission. With this stressful (at least in terms of the rocket) part of the mission past it. Mission managers were able to proceed with the next phase of the flight.
Atlas Booster Engine Cutoff took place roughly four minutes and four seconds after the rocket had left the launch pad far below with separation between the rocket’s first and second stages taking place six seconds after that.
At about 260 seconds into the flight, the rocket’s Centaur upper stage activated. At about four minutes and 28 seconds into the mission, the payload fairing – its role in shielding the GPS IIF-11 spacecraft aloft complete – was jettisoned.
After having been active for a little shy of 13 minutes, the Centaur upper stage had completed its first burn. It reactivated some three hours later for an additional burn which lasted about a minute and 27 seconds.
After a period of about three hours and 23 minutes, and some 13 seconds, the GPS IIF 11 separated from the Centaur upper stage and was ready to begin its mission. With today’s successful mission, there only remains the GPS IIF-12 satellite to complete the deployment of the constellation.
By the numbers – today’s launch was the 101st ULA launch overall, the 59th operational GPS satellite to be launched on a ULA booster, as well as the 59th flight of an Atlas V rocket. The flight of GPS IIF-11 was the 29th time that the 401 configuration of the launcher was employed.
The Atlas V rocket’s various components are produced in Decatur, Alabama (core stage), Harlingen, Texas ( Payload Fairing, Boattail, Centaur Forward Adapter, Aft Stub Adapter, & Launch Vehicle Adapter Fabrication), West Palm Beach, Fl (Centaur’s RL-10C rocket engine) and Khimki, Russia (the NPO Energomash RD-180 rocket engine).
From United Launch Alliance’s point of view, the launch that took place earlier on Halloween will help to strengthen a resource that has become commonplace.
“Congratulations to the entire team on today’s successful launch of the GPS IIF-11 satellite! Today’s launch was made possible by the exceptional performance and teamwork exhibited by the entire team, including the men and women of ULA, our many mission partners, and our U.S. Air Force customer,” said Jim Sponnick, ULA vice president, Atlas and Delta Programs via a release issued by the company. “GPS is omnipresent in our everyday lives and the system provides a critical service to the all of those serving in our military around the world. All of the operational GPS satellites have been launched on Atlas and Delta rockets and the U.S. Air Force does an outstanding job of operating this essential system.”
Video courtesy of SpaceFlight Insider
Jason Rhian spent several years honing his skills with internships at NASA, the National Space Society and other organizations. He has provided content for outlets such as: Aviation Week & Space Technology, Space.com, The Mars Society and Universe Today.