Galaxy 37 | Falcon 9 Block 5

Lift Off Time
(Subject to change)
August 03, 2023 – 04:15 UTC | 00:15 EDT
Mission Name
Galaxy 37, a telecommunication satellite
Launch Provider
(What rocket company is launching it?)
(Who’s paying for this?)
Falcon 9 Block 5, B1077-6; 58.52 day turnaround
Launch Location
Space Launch Complex 40, Cape Canaveral Space Force Station, Florida, USA
Payload mass
Unknown, ~3,500 kg each
Where are the satellites going?
Geostationary Transfer Orbit (GTO)
Will they be attempting to recover the first stage?
Where will the first stage land?
~663 km downrange on Just Read the Instructions

Tug: Crosby Skipper; Support: Bob
Will they be attempting to recover the fairings?
The fairing halves will be recovered from the water ~760 km downrange by Bob
Are these fairings new?
Probably not
How’s the weather looking?
The weather is currently 90% GO for launch (as of July 31, 13:30 UTC)
This will be the:
– 243rd Falcon 9 launch
– 176th Falcon 9 flight with a flight-proven booster
– 184th re-flight of a booster
– 50th re-flight of a booster in 2023
– 213th booster landing
– 139th consecutive landing (a record)
– 53rd launch for SpaceX in 2023
– 136th SpaceX launch from 
– 117th orbital launch attempt of 2023
Where to watch
Official Livestream

What’s This All Mean?

SpaceX is set to launch a single communication satellite to geostationary transfer orbit (GTO) for Intelsat. The Galaxy 37 satellite will be launched from SpaceX’s launch pad Space Launch Complex 40, at the Cape Canaveral Space Force Station, in Florida, USA. Following deployment from the second stage, the satellite will spend the coming months raising its orbits to its operational orbit in geostationary Earth orbit (GEO). It is expected that the satellites will be operational by late 2023.

What Are The Galaxy 37 Satellite?

The Galaxy 37 is a replacement for Intelsat’s aging satellites in GEO. The Galaxy constellation satellites are C-band-only communication satellites, allowing the satellites to service North America with television broadcasting.

The satellites are thought to be based on the GEOStar-3 satellite Bus and is equipped with the IHI BT-4 propulsion module. Built by the Japanese company IHI Aerospace, the BT-4 is a pressure-fed engine that runs on N2O4 and Hydrazine. It produces 500 N of thrust in a vacuum with an ISP of ~320 seconds. This engine is also used on Cygnus and HTV — two ISS resupply vehicles.

The Galaxy 33 satellite is being prepared for shipping (Credit: Intelsat)

These satellites are a part of Intelsat order of six new satellites: four of which will be built by Maxar Technologies and two which will be built by Northrop Grumman. If all of these satellites are operational by December 5, 2023, Intelsat will receive $4.87 billion from the Federal Communication Commission (FCC) in the FCC’s attempts to clear the 300 MHz spectrum, which is used in cellular 5G networks.

The satellites have an expected lifespan of 15 years, and they are powered by two deployable solar arrays and batteries. While neither Intelsat or Maxar have released the mass of the satellite, it is expected that the satellite masses roughly 3,500 kg based on previous satellites and the Falcon 9’s performance.

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 nine 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 the flight, and be able to successfully place the payload into orbit.

The Merlin engines are ignited by triethylaluminum and triethylborane (TEA-TEB), which instantly burst into flames when mixed in the presence of oxygen. 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.

SpaceX is currently flying two different versions of the MVacD engine’s nozzle. The standard nozzle design is used on high-performance missions. The other nozzle is a significantly shorter version of the standard, decreasing both performance and material usage; with this nozzle, the MVacD engine produces 10% less thrust in space. This nozzle is only used on lower-performance missions, as it decreases the amount of material needed by 75%. This means that SpaceX can launch over three times as many missions with the same amount of Niobium as with the longer design.

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 composite-overwrapped pressure vessels (COPVs) for pressurization control, and additional TEA-TEB.

falcon 9 block 5, launch
Falcon 9 Block 5 launching on the Starlink V1.0 L27 mission (Credit: SpaceX)

Falcon 9 Booster

The booster supporting the Galaxy 37 mission is B1077-6. As the name implies, this booster has supported five previous missions; upon successful landing, its designation will change to B1077-7.

B1077’s missionsLaunch Date (UTC)Turnaround Time (Days)
Crew-5May 10, 2022 16:00N/A
GPS III SV06January 18, 2023 12:24104.85
Inmarsat I-6February 18, 2023 03:5930.65
Starlink Group 5-10March 29, 2023 20:0139.67
Dragon CRS-2 SpX-28June 05, 2023 15:4767.82

Following stage separation, the Falcon 9 will conduct two burns. These burns aim to softly touch down the booster on SpaceX’s autonomous spaceport drone ship Just Read The Instructions.

falcon 9 booster, landing, drone ship
Falcon 9 landing on Of Course I Still Love You after launching Bob and Doug (Credit: SpaceX)

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, however, at the end of 2020 this program was canceled due to safety risks and a low success rate. On Galaxy 37, SpaceX will attempt to recover the fairing halves from the water with its recovery vessel Bob.

In 2021, SpaceX started flying a new version 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.

All times are approximate

00:38:00SpaceX Launch Director verifies go for propellant load
00:35:00RP-1 (rocket-grade kerosene) loading underway
00:35:001st stage LOX (liquid oxygen) loading underway
00:16:002nd stage LOX loading underway
00:07:00Falcon 9 begins engine chill prior to launch
00:01:00Command flight computer to begin final prelaunch checks
00:01:00Propellant tank pressurization to flight pressure begins
00:00:45SpaceX Launch Director verifies go for launch
00:00:03Engine controller commands engine ignition sequence to start
00:00:00Falcon 9 liftoff

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