Featured image credit: SpaceX
| June 17, 2021 – 16:09:35 UTC | 12:09:35 EDT |
|---|---|
Mission Name | GPS III Space Vehicle 05, the 5th GPS block 3 satellite named Neil Armstrong |
Launch Provider | SpaceX |
Customer | United States Space Force |
Rocket | Falcon 9 Block 5 B1062-2; 224 day turn around |
Launch Location | Space Launch Complex 40 (SLC-40), Cape Canaveral Space Force Station, Florida, USA |
Payload mass | ~3,880 kg (~8,550 lb) |
Where did the satellite go? | 20,180 x 20,180 km medium-Earth Orbit |
Did they attempt to recover the first stage? | Yes |
Where did the first stage land? | B1062-2 successfully landed 647 km downrange on Just Read the Instructions Tug: Finn Falgout; Support: GO Quest |
Did they attempt to recover the fairings? | Yes, Hos Briarwood attempted fairing recovery from the water 758 km downrange; outcome TBD |
Were the fairings new? | Yes |
This was the: | – 1st fairing recovery mission for Hos Briarwood – 122nd Falcon 9 launch – 63rd Falcon 9 flight with a flight proven booster – 67th re-flight of a booster – 29th 2nd flight of a booster – 18th re-flight of a booster in 2021 – 88th booster landing – 19th launch for SpaceX in 2021 – 73rd SpaceX launch from SLC-40 – 56th orbital launch attempt of 2021 |
Where to watch | Official replay |
How did it go?
SpaceX successfully launched the GPS III SV05 mission to a medium-Earth orbit on the Falcon 9 for the United States Space Force. The Falcon 9 lifted off from Space Launch Complex 40 (SLC-40) at the Cape Canaveral Space Force Station and the booster successfully landed on Just Read the Instructions (JRtI) about 8 minutes after launch. This launch marked the fifth launch of a GPS block III satellite to date.
What is the GPS 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 (GNNS), providing worldwide coverage for geolocation and time; Russia uses their own GLONASS for GNNS and the European union uses Galileo. Currently, there are 31 active GPS satellites in orbit, with roughly two dozen more satellites planned.
Active GPS Satellites:
Out of the 31 active satellites in orbit, there are four different versions with two different blocks. The block of a GPS satellite is given by Roman Numerals in its name and the version is given by a letter after the numerals. The newest satellites in the constellation are the four block III satellites. The first block III satellite was launched on a Falcon 9 in 2018, with other launches occurring in 2019 and 2020. There are also 12 operational GPS Block IIFs, which launched from 2010 to 2016. Next, 7 operational GPS Block IIR-Ms; they launched from 2005-2009. Finally, there are 8 operational Block IIRs, launched between 1997 and 2004. Through the progression of these blocks, the Space Force has increased satellite lifespan, increased the precision and accuracy of both position and time, and made the constellation significantly harder to jam.
For the civilian population, GPS provides an impressive 30 cm to 500 cm of accuracy, with even more accuracy for the United States department of defense. This is especially impressive as each satellite is a circular orbit with an orbital height of 20,180 km.
What is GPS Block III?
GPS Block III is the third major iteration of the GPS satellite and is designed and manufactured by Lockheed Martin. Each satellite is designed to have a 15 year lifespan; however based on previous blocks lasting over twice as long as their planned 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 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
- Military M-code
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.
What is Falcon 9 Block 5?
The Falcon 9 Block 5 is SpaceX’s partially reusable two-stage medium-lift launch vehicle. The vehicle consists of a reusable first stage, an expendable second stage, and, when in payload configuration, a pair of reusable fairing halves.
First Stage
The Falcon 9 first stage contains 9 Merlin 1D+ sea level engines. Each engine uses an open gas generator cycle and runs on RP-1 and liquid oxygen (LOx). Each engine produces 845 kN of thrust at sea level, with a specific impulse (ISP) of 285 seconds, and 934 kN in a vacuum with an ISP of 313 seconds. Due to the powerful nature of the engine, and the large amount of them, the Falcon 9 first stage is able to lose an engine right off the pad, or up to two later in flight, and be able to successfully place the payload into orbit.
The Merlin engines are ignited by TEA-TEB. During static fire and launch the TEA-TEB is provided by the ground service equipment. However, as the Falcon 9 first stage is able to propulsively land three of the Merlin engines (E1, E5, and E9) contain TEA-TEB canisters to relight for the boost back, reentry, and landing burns.
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 grey strip, which helps keep the RP-1 warm, an increased number of COPVs for pressurization control, and additional TEA-TEB.
Falcon 9 Booster B1062
The booster supporting the GPS III SV05 mission is B1062. B1062 previously supported the GPS III SV04 mission on November 5, 2021. This mission marked the first flight proven Falcon 9 to launch a Space Force mission.
Following stage separation, the Falcon 9 successfully conducted two burns. These burns softly touched down the booster on SpaceX’s autonomous spaceport drone ship Just Read the Instructions.
Falcon 9 Fairings
The Falcon 9’s fairing consists of two dissimilar reusable halves. The first half (the half that faces away from the transport erector) is called the active half, and houses the pneumatics for the separation system. The other fairing half is called the passive half. As the name implies, this half plays a purely passive role in the fairing separation process, as it relies on the pneumatics from the active half.
Both fairing halves are equipped with cold gas thrusters and a parafoil which are used to softly touch down the fairing half in the ocean. SpaceX used to attempt to catch the fairing halves in nets on GO Ms. Tree and GO Ms. Chief. However, at the end of 2020 this program was canceled due to safety risks and a low success rate. On GPS III SV05, SpaceX attempted to recover both of the fairing halves from the water with their recovery vessel Hos Briarwood.
SpaceX is currently flying two slightly different versions of the Falcon 9 fairing. The new “upgraded” version has vents only at the top of each fairing half, by the gap between the halves, whereas the old version had vents placed spread equidistantly around the base of the fairing. Moving the vents decreases the chance of water getting into the fairing, making the chance of a successful scoop significantly higher.
An active Falcon 9 fairing half (Credit: Greg Scott) 
Falcon 9 passive fairing half (Credit: Greg Scott) 
Half of the fairing being taken off Go. Navigator. (Credit: Lupi) 
A passive fairing half being unloaded from Shelia Bordelon after the Starlink V1.0 L22 mission (Credit: Kyle M)
GPS III SV05 Full Mission Profile
Hr/Min/Sec Event
– 00:38:00 SpaceX Launch Director verifies go for propellant load.
– 00:35:00 RP-1 (rocket grade kerosene) loading underway.
– 00:35:00 1st stage LOx (liquid oxygen) loading underway
– 00:16:00 2nd stage LOx loading underway
– 00:07:00 Falcon 9 begins engine chill prior to launch
– 00:01:00 Command flight computer to begin final prelaunch checks
– 00:01:00 Propellant tank pressurization to flight pressure begins
– 00:00:45 SpaceX Launch Director verifies go for launch
– 00:00:03 Engine controller commands engine ignition sequence to start
– 00:00:00 Falcon 9 Liftoff
GPS III SV05 Launch, Landing, and Satellite Deployment*
Hr/Min/Sec Event
00:01:12 Max Q (moment of peak mechanical stress on the rocket)
00:02:32 1st stage main engine cutoff (MECO)
00:02:35 1st and 2nd stages separate
00:02:43 2nd stage engine starts (SES-1)
00:03:27 Fairing deployment
00:06:18 1st stage entry burn begins
00:08:07 2nd stage engine cutoff (SECO-1)
00:08:33 1st stage landing
01:03:35 2nd stage engine starts (SES-2)
01:04:19 2nd stage engine cutoff (SECO-2)
01:29:20 GPS III SV05 payload deploy
* All times are approximate
