Falcon 9 launches Arabsat 7B following weather delays

by Trevor Sesnic

SpaceX finally launched the Arabsat 7B satellite to geostationary transfer orbit (GTO) for Arabsat atop its Falcon 9 rocket.

The launch occurred May 27 at 00:30 PM EDT (04:30 UTC) from Space Launch Complex 40 (SLC-40), at the Cape Canaveral Space Force Station in Florida. The launch suffered several delays due to unacceptable launch weather.


This launch utilized B1062-14; the -14 signifies that this was the booster’s 14th flight to space and back. B1062 has previously supported the GPS III SV04 and SV05 missions, Inspiration4, Axiom-1, Nilesat-301, OneWeb 17, and seven Starlink missions.

Following launch, the booster landed on SpaceX’s autonomous spaceport drone ship Just Read the Instructions (JRTI), which was tugged east into the Atlantic Ocean by SpaceX’s multi-purpose recovery vessel Bob.

Falcon 9’s 5.2-meter payload fairing transported Arabsat 7B (also known as Badr 8) satellite for launch, which is Arabsat’s first seventh-generation satellite, built on Airbus’ Neostar-neo satellite bus. After launch, the satellite will spend the next four-to-five months raising its orbit into the 26-degree East slot in geostationary Earth orbit (GEO). 

This bus uses electric propulsion and is designed to last 15 years in orbit. Giving the satellite 17 kilowatts of power are two large deployable solar arrays, which are backed up by batteries to maintain spacecraft operations during the solar night.

Badr 8 carries the new TELEO optical communications payload demonstrator, enabling high-capacity analog optical feeder link communications. Airbus expects this method of data transfer to be highly robust to jamming.

The satellite will provide satellite TV and telecommunication services to central Africa, Europe, and the Middle East.

Falcon 9’s now very familiar countdown sequence starts at T-38 minutes when the launch director will verify that all systems are go for propellant load. Loading of propellant starts at T-35 minutes with liquid oxygen (LOX) being loaded on the first stage and rocket propellant 1 (RP-1) being fueled on both the first and second stages.

RP-1 load wraps up on the second stage by T-20 minutes when the transporter erector purges its lines ahead of LOX load. This is done to cool down and clean the lines ahead of super-chilled LOX flowing through them at T-16 minutes.

At T-7 minutes, the Falcon 9 runs small amounts of liquid oxygen through the nine Merlin 1D engines on the first stage. Known as engine chill, this process cools down the engines slowly, ensuring that they do not crack from thermal shock when LOX flows through them at engine ignition.

At T-1 minute, Falcon 9 enters start-up. This is when the vehicle’s onboard computers take control of the countdown. Also at this time, the vehicle begins to increase pressure in all four main tanks, making them more rigid for flight loads.

45 seconds before launch, the Launch Director verifies that they are go for launch. 

Manual aborts can be called by the launch operators up until T-10 seconds; after T-10 seconds, technical aborts will only be handled by the vehicle itself and not the ground operators.

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

Falcon 9 (B1058-9) launch Starlink Group 4-1. (Credit: SpaceX)

Once Falcon 9 ensured that all systems are nominal, it commanded for the hydraulic clamps at the base of the vehicle to release, letting the Falcon 9 lift off from the pad.

B1062 burned for two minutes and 33 seconds before commanding shutdown of all nine of its engines. The stages then separated and the second stage ignited its singular vacuum-optimized Merlin engine, in an event known as second engine start one (SES-1). At T+3:22, the fairing halves deployed from the second stage. Both halves then use parafoils and cold gas thrusters to softly splash down in the Atlantic Ocean, for recovery by Bob

The first stage then completed a reentry and landing burn, softly touching down on JRTI. This marked SpaceX’s 195th booster landing and 121st consecutive landing.

After SES-1, stage two coasted until T+29:03, when it ignited its engine again for 59 seconds. Badr 8 then deploy at T+37:13. 

Arabsat 7B marked SpaceX’s eighth launch of the month, and it has two more planned. This will be the most SpaceX launches in a single month to date.

(Lead image: Falcon 9 launches latest mission. Credit: NSF)

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