SpaceX to launch Eutelsat-10B on final flight of booster B1049

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| 2022-11-21 18:23:28

SpaceX is set to launch the Eutelsat-10B communication satellite into a supersynchronous geostationary transfer orbit. A Falcon 9 Block 5 rocket carrying the satellite will lift off from Space Launch Complex 40 at the Cape Canaveral Space Force Station in Florida with liftoff scheduled for Monday, Nov. 21 at 9:57 PM EST (02:57 UTC on Nov. 22). This will mark SpaceX’s 53rd mission of 2022 – keeping an average of a launch every 6.13 days.

Citing the thick cloud layer, cumulus cloud, and disturbed weather rules, the Space Launch Delta 45 released a launch mission execution forecast putting the probability of violation of weather constraints at 70%. Additionally, the forecast cites recovery weather as a moderate risk and solar activity and upper-level wind shear as a low risk.

In the event of a delay, SpaceX has a backup launch opportunity approximately 24 hours later, on Nov. 22, when the weather deteriorates to just 10% go for launch.

In order for the vehicle to have the performance to place the satellite into its planned higher-energy orbit, the booster, B1049, will be expended, splashing down in the Atlantic Ocean. This will mark the third expended Falcon booster of this year, with SpaceX intentionally expending Falcon Heavy’s center core on the USSF-44 mission and the Falcon 9 booster B1051 during the Galaxy 31 & 32 launch.

Ahead of being expended, B1049 – which last flew on Sep. 14, 2021, on the Starlink Group 2-1 mission – donated its interstage to B1052, which was converted from a Falcon Heavy minus-Y side core to a Falcon 9 booster.

The older Falcon 9 boosters – built before B1056 – feature a different interstage mounting mechanism from the newer boosters, which now consist of fewer pins. It is thought that the reduction of pins mounting the interstage reduces the amount of work needed to convert from a Falcon 9 to a Falcon Heavy side booster, and visa versa.

For this reason, coupled with SpaceX’s intentions to not convert B1053 to a Falcon 9, SpaceX only needed a single old interstage, explaining why B1051 didn’t also lose its interstage before its final mission. To replace the interstage donated to B1052, SpaceX installed a white interstage, left over from the pre-block-5 Falcon 9 v1.2 or “Full Thrust” design.

The oldest active booster in SpaceX’s fleet, B1049 was the fourth Falcon 9 Block 5 produced and has supported 10 previous missions. Following the launch, the Falcon 9 fleet remaining in service will be 12 boosters strong.

Inside the Falcon 9’s 5.2-meter payload fairing lies the Eutelsat-10B spacecraft: a communication satellite built by Thales Alenia Space for Eutelsat Communications to provide maritime and in-flight connectivity. Eutelsat-10B is to replace Eutelsat-10A – which is due to reach its end of life in 2023 – in the 10-degree-East slot where it provides service to North and South America as well as Asia.

The satellite is based on the Spacebus Neo-200 bus; while the mass of the satellite has not been stated by Eutelsat, based on other spacecraft built on this satellite bus, it is estimated to be around 4,500 kg.

The satellite will carry two multi-beam high-throughput satellite (HTS) Ku-band payloads. The first will provide the North Atlantic corridor, Europe, the Mediterranean basin, and the Middle East with high throughput in areas with heavy air and sea traffic. The second payload will extend coverage across the Atlantic Ocean, Africa, and the Indian Ocean. Each of these HTS payloads will have roughly 35 gigabits per second of throughput.

The satellite will also be equipped with 36 Ku-band transponders and 20 C-band transponders. It is equipped with plasma thrusters for control and two large solar arrays to generate power.

🚀 EUTELSAT 10B satellite launching soon!
➡️ Bringing new HTS capacity for in-flight and maritime connectivity
services.
👀 Stay tuned!

Images: @Thales_Alenia_S (#EUTELSAT 10B #satellite constructor)#connectivity #satcoms #launchingsoon #maritime #aviation pic.twitter.com/t2oxigvzz7

— Eutelsat (@Eutelsat_SA) November 17, 2022

At T-38 minutes before Falcon 9 is due to launch, the launch director will verify that the vehicle is go for propellant loading. Pending all teams being go, three minutes later, at T-35 minutes, SpaceX will begin loading cooled RP-1 onto both the first stage and the second stage, as well as superchilled liquid oxygen (LOX) onto the first stage.

Unlike other rockets, the Falcon 9 uses RP-1 which is cooled to -7° C and LOX which is cooled to -205° C. By further chilling, and therefore increasing the density of, propellants SpaceX can get more performance out of the Falcon 9. This comes with the trade-off that SpaceX is unable to hold the countdown once propellant loading has started.

At around T-20 minutes, a large cloud will form and be vented from the strongback, signifying that the second stage is fully fueled with RP-1, and is ready for LOX loading. This large vent from the strong back is the purging and cooling down of the propellant lines ahead of the second stage LOX load, which starts at T-16 minutes.

At T-7 minutes, the Falcon 9 will run small amounts of liquid oxygen through the nine Merlin 1D engines on the first stage. This process, known as engine chill, is done to cool down the engines slowly so that they do not crack from thermal shock when superchilled LOX flows through them at engine ignition.

At T-1 minute, Falcon 9 will enter startup. At this time the rocket is fully in charge of its countdown—all technical aborts from this point forward will be handled by the vehicle itself, and not the ground operators. The ground operators will only abort the countdown after this point in case of a weather or range violation.

Also at T-1 minute, Falcon 9 will begin to pressurize its tanks for flight. The stage is kept at a higher pressure, protecting itself from forces of ascent. 45 seconds before launch the launch director will verify that they are go for launch. 

At T-3 seconds, the booster’s flight computer will command the ignition of the nine Merlin 1D engines. The engines on the first stage ignite in pairs to reduce startup transients and loads on the vehicle. 

Once the vehicle’s onboard computer has ensured that all systems are nominal, it will command the hydraulic clamps at the base of the vehicle to release, letting the Falcon 9 lift off from the pad.

Streak shot of Falcon 9 launching the Starlink Group 4-34 mission to orbit. (Credit: Stephen Marr for NSF)

B1049 will burn for approximately two minutes and 43 seconds before shutting down its first-stage engines — once again staggered to reduce loads on the vehicle. The vehicle will then command a high-pressure helium circuit to release the latches connecting the first and second stages. Four pneumatic pushers—three radially around the interstage and one in the center of the interstage — will push the stages apart. The second stage’s single vacuum-optimized Merlin will ignite several seconds later.

At around three minutes and 36 seconds after launch, the vehicle will command the latches connecting the fairing halves release. Shortly after, the fairing halves will be pushed apart using four pneumatic pushers, stored in the active fairing half. The fairings will then use RCS to reorient themselves as they re-enter the Earth’s atmosphere, before deploying a parafoil to achieve a soft landing in the water. The fairing halves will then be recovered by SpaceX’s fairing recovery vessel, Doug.

About eight minutes and five seconds after launch, the second stage will shut down its Merlin Vacuum engine. The stage will then coast for about 18 minutes before igniting again for a further one minute and nine seconds. This second burn will place the stage in its planned supersynchronous transfer orbit and will also likely reduce the orbital inclination. It is in this orbit that Eutelsat-10B will be deployed from the second stage.

Following Monday’s launch, SpaceX currently has at least three more missions scheduled for November: CRS-26 from Launch Complex 39A (LC-39A) at the Kennedy Space Center to send supplies to the International Space Station, HAKUTO-R Mission 1 which will send a commercial lunar lander to the moon from Space Launch Complex 40 (SLC-40) at the Cape Canaveral Space Force Station, and Starlink Group 2-4 from Space Launch Complex 4E (SLC-4E) at Vandenberg Space Force Base.

(Lead image: Falcon 9 on SLC-40 ahead of the Starlink v1.0 L3 launch. Credit: Thomas Burghardt for NSF)

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