Lift Off Time (Subject to change)
Mission Name and what it is
|GPS Block III SV04: The fourth Third Generation Global Positioning System (GPS) satellite|
Launch Provider (What rocket company is launching it?)
Customer (who’s paying for this?)
|United States Space Force|
|Falcon 9 Block 5 B1062.1|
|Space Launch Complex 40 (SLC-40), Cape Canaveral Air Force Station, Florida, USA|
|3,880 kg (8,553 pounds)|
Where’s the satellite going?
|Medium Earth Orbit – 20,200 km (12,500 miles), 55° inclination|
How’s the weather?
Will they be attempting to recover the first stage?
Where will the first stage land?
|The booster will land 635 km downrange on SpaceX’s autonomous spaceport drone ship (ASDS) Just Read the Instructions|
Will they be attempting to recover the fairing?
|Fairing recovery is expected|
This will be the:
Where to watch
|SpaceX official Stream If you happen to be in the area, here’s where you can watch in person!|
What’s all this mean?
SpaceX’s Falcon 9 rocket will launch the GPS Block III SV04 satellite for the US Space Force. SV04 is part of the United States Space Force’s next generation GPS constellation. It is launching from Space Launch Complex-40 (SLC-40) at the Cape Canaveral Air Force Station (CCAFS). This launch will mark the fourth GPS Block III launch 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, providing worldwide coverage for geolocation and time. Currently, there are 31 active GPS satellites in orbit, with an additional 24 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 is another Block III satellite that is not yet in its operational orbit. 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.
What is GPS Block III?
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 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. Block 5 is the final iteration of the Falcon 9; the goal is to apply all the lessons learned from 56 previous Falcon 9 pre-Block 5 flights into a human-rated reusable rocket. The Falcon 9 contains 3 main components: a reusable first stage, an expendable second stage, and a reusable fairing.
Block 5 updates:
SpaceX introduced a lot of changes on Block 5, allowing it to become the crewed-launching reusable rocket that we know today. To start, the Composite Overwrapped Pressure Vessel (COPV) had to undergo a complete redesign. NASA mandated the COPV redesign, as it had been the cause of both of the Falcon 9 failures: AMOS-6 and CRS-7.
Alongside with certification for human spaceflight, Block 5 came with a number of other major changes. To increase the amount of flight each booster could handle, and decrease the turnaround time, SpaceX reinforced the landing legs, upgraded the grid fins, and added a carbon fiber interstage. They also added heat resistant external paint and upgraded the engines. For more information about the changes in Block 5, and the other Blocks of the Falcon 9, check out this video by the Everyday Astronaut:
Falcon 9 Booster B1062
The booster supporting this mission is B1062. This is the booster’s first flight, which will change its designation to B1062.1.
Following stage separation, the Falcon 9 will conduct 3 burns. These burns will softly touch down the booster on Just Read The Instructions.
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.
What is the gray stripe on the second stage?
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. 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 as 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.
GPS Block III SV04 Full Mission Profile
– 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
Launch, Landing, and Satellite Deployment*
00:01:11 Max Q (moment of peak mechanical stress on the rocket)
00:02:31 1st stage main engine cutoff (MECO)
00:02:35 1st and 2nd stages separate
00:02:42 2nd stage engine start (SES-1)
00:03:28 Fairing deployment
00:06:45 1st stage entry burn complete
00:08:07 2nd stage engine cutoff (SECO-1)
00:08:30 1st stage landing
01:03:28 2nd stage engine start (SES-2)
01:04:13 2nd stage engine cutoff (SECO-2)
01:29:14 GPS Block III SV04 deployment
* All times are approximate