SpaceX Falcon 9 Block 5 - GPS III SV03 - Launching June 30, 2020
Screenshot of GPS III SV03 from SpaceX webcast
Mission Rundown: SpaceX Falcon 9 B5 - GPS III SV03
Written: January 10, 2021
So We got ourselves another new rocket.
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 B1060-1 will launch the GPS Block III SV03 satellite for the American military. SV03 is part of the United States Space Force’s new generation GPS constellation. It is launching on June 30, at 20:10:46 UTC, from Space Launch Complex 40 - SLC-40 at the Cape Canaveral Space Force Station (CCSFS).
This GPS mission marks the 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.
Copy and lift of the GPS III SV03 mission view by Geoff Barrett from Tim Dodd’s homepage
The payload
Under the military designation USA-304, also known as GPS-III SV03 or Matthew Henson, is an United States navigation satellite which forms part of the Global Positioning System. It was the third GPS Block III satellite to be launched.
USA-304 was launched by SpaceX on 30 June 2020 at 20:10 UTC atop Falcon 9 booster B1060. The launch took place from SLC-40 of the Cape Canaveral Air Force Station, and placed USA-304 directly into semi-synchronous orbit. About eight minutes after launch, Falcon 9 B1060 successfully landed on Just Read the Instructions.
As of 2021, USA-304 was in a 55.2 degree inclination orbit with a perigee of 20,164 kilometers (12,529 mi) and an apogee of 20,214 km (12,560 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.
Screenshot of GPS III SV03 deploying from SpaceX Webcast. It’s still a big friggin house
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.
The Falcon 9 second stage
The Falcon 9 second stage is the only expendable part of the Falcon 9. It contains a singular MVacD# engine that produces 992 kN of thrust and an ISP of 348 seconds. The second stage is capable of doing several burns, allowing the Falcon 9 to put payloads in several different orbits.
For missions with many burns and/or long coasts between burns, the second stage is able to be equipped with a mission extension package. When the second stage has this package it has a gray stripe, which helps keep the RP-1 warm in the sunlight, and has an increased number of COPVs for pressurization control, plus additional TEA-TEB.
As objects in space are really hot while in the sun, and really cold while in a shadow, maintaining the cryogenic temperature of liquid oxygen is no easy feat. SpaceX has added the gray stripe because it acts as a “heatsink” for the LOX tank, warming up the RP-1 instead of the LOX. This is done to ensure that the propellent temperatures are good for a second engine start (SES) over an hour after launch. This is ideal as RP-1’s boiling point is around 220 K higher and can handle the slight increase in temperature. Furthermore, RP-1 has a higher specific heat capacity further increasing the stripe’s effect.
For some unknown reason or source the second stage is designated B2100 by Tim Dodd. Well be that as it may, B2100 conducted three burns in its short glorious career. The first insertion burn from T+00:02:45 to SECO at T+00:08:13 in order to circularize the LEO Low Earth Orbit. The second transfer burn from T+01:03:32 to SECO-2 at T+01:04:18 to raise the GPS satellite halfway towards its MEO Medium Earth Orbit, where it on its own will circularize itself in its operational position.
Having delivered its payload only one deorbit burn remains with what little fuel is left in the tanks, so a brake burn is performed at apogee lowering the perigee towards the Indian Ocean south east of Africa.
- So rest in peace. B2100 - In Davy Jones locker -
