SpaceX Falcon 9 Block 5 - GPS III SV04 - Launching November 5, 2020
Screenshot of GPS III SV04 from SpaceX webcast
Mission Rundown: SpaceX Falcon 9 B5 - GPS III SV04
Written: July 28, 2021
We need to find our way in the dark
SpaceX is being commissioned by the US Air Force to launch the first Third Generation Global Positioning System (GPS) satellite to orbit. This was originally planned as the second GPS launch with ULA launching the first. The US Air Force changed the order of launches because SpaceX sued the US Government to get the launch contract in a bidding war with ULA, who had won a 36 launch-block without competitive bidding from SpaceX.
After the lawsuit was dropped, the Air Force followed through on its promise and publicly requested fixed-price contract bids for the launch of the second GPS III satellite. The competitive bid was submitted as part of the Air Force’s Evolved Expendable Launch Vehicle (EELV) program – the “Expendable” part of which being a holdover from the era of full expendability of rockets. The Falcon 9 is an expendable part of the EELV program even though it is capable of being recovered and reused.
SpaceX Falcon 9 rocket B1062-1 will launch the GPS Block III SV04 satellite for the American military. SV04 is part of the United States Space Force’s new generation GPS constellation. It is launching Thursday at 18:24:23 EST on November 5, 2020 from Space Launch Complex-40 - SLC-40 at the Cape Canaveral Space Force Station (CCSFS).
Booster B1062 completed another static fire at SLC-40 on 31 October to validate the fix.
The refurbishment of Merlin 1D# and MVac 1D# was faulty, when masking material was found in the relief valves causing it to abort October 2. Engines on at least three Falcon 9 rockets have been replaced, refurbished and tested in McGregor, Texas. Learn more.
A rare double Landing Zone with three days worth of shifting positions by the recovery fleet
SpaceX is the first entity ever that recovers and reflies its fairings. The recovery vessels, Go Ms. Tree and Go Ms. Chief, will most likely attempt to recover the fairing halves.
After being jettisoned, the two fairing halves will use cold gas thrusters to orientate themselves as they descend through the atmosphere. Once at a lower altitude, they will deploy parafoils to help them glide down to a soft landing for recovery.
The Type 2.2 lifeboat sized fairings - 34 x 17 feet with 8 vents ports, a thermal steel tip, a lowered square protrusion and acoustic tiles mounted on the inside.
This GPS mission didn’t feature another return of the gray stripe around the RP-1 tank on the second stage. The stripe first appeared on July 25, 2019, for the launch of CRS-18.
GPS satellite constellation
GPS, or Global Positioning System, is a medium-Earth orbit satellite constellation which is operated by the United States Space Force. It is America’s global navigation satellite system, providing worldwide coverage for geolocation and time. Currently, there are 31 active GPS satellites in orbit, with an additional 25 planned.
Out of those 31 active satellites, there are four different models, and two different blocks. From newest to oldest there are two operational GPS Block IIIs, which were launched in 2018 and 2019. There are also 12 operational GPS Block IIFs, which launched from 2010-2016. Next, 7 operational GPS Block IIR-Ms; they launched from 2005-2009. Finally, there are 10 operational Block IIRs, launched between 1997 and 2004. Learn more about the block versions here.
The GPS constellation brings impressively accurate readings to the civilian population, with even more accuracy for the branches of the military. For the civilian population, GPS provides an impressive 500-30 cm of accuracy. This is especially impressive as each satellite is a circular orbit with an orbital height of 20,180 km. GPS Block III plans to improve on this even further.
The payload
Under the military designation USA-309, also known as GPS-III SV04 or Sacagawea, is an United States navigation satellite which forms part of the Global Positioning System. It was the fourth GPS Block III satellite to be launched.
USA-309 was launched by SpaceX on 5 November 2020 at 23:24 UTC atop Falcon 9 booster B1062. The launch took place from SLC-40 of the Cape Canaveral Air Force Station, and placed USA-309 directly into semi-synchronous orbit. About eight minutes after launch, Falcon 9 B1062-1 successfully landed on Of Course I Still Love You OCISLY.
As of 2021, USA-309 was in a 54.9 degree inclination orbit with a perigee of 20,181 kilometers (12,540 mi) and an apogee of 20,198 km (12,550 mi).
GPS Block III is the third major iteration of the GPS satellite. Each satellite was designed and manufactured by Lockheed Martin. Each satellite is designed to have a 15 year lifespan, but based on previous blocks lasting over twice as long as their lifespan, each satellite will likely last longer.
The goal of GPS Block III was to provide enhanced signal reliability, accuracy, and integrity. The satellites will build upon, or improve, features included on the Block IIR-M and IIF satellites are including:
L1C signal on the 1575.42 MHz L1 frequency
L2C signal on the 1227.6 MHz L2 frequency
L5 “Safety of Life” signal on the 1176.45 MHz L5 frequency
The first satellite was supposed to launch in 2014, but experienced many delays that pushed the first launch back to December 2018. The 10th, and final, GPS Block III satellite is expected to launch NET Q2 2023.
Under the build contract, Lockheed Martin served as prime manufacturer and provided the A2100 bus structure for the satellites. Additionally, Orbital ATK, now Northrop Grumman Innovation Systems, provided the propellant tanks, the pressure tanks and the propulsion jets, and Northrop Grumman Astro Aerospace provided the eight deployable JIB antennas.
Under the administration of President Barack Obama, the Next Generation GPS Operational Control System contract was awarded to Raytheon on 25 February 2010 to build the ground control system for the GPS III satellites.
The first GPS III satellite was originally to launch in 2014, And was scheduled to be taken to orbit aboard a United Launch Alliance (ULA) Delta IV M+ rocket, but delays due to late technology, late build deliveries and lawsuits pushed the launch into december 2018.
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