SpaceX is about to launch one other batch of 56 Starlink web communication satellites into low Earth orbit (LEO) on Sunday, May 14, at 01:03 EDT (05:03 UTC). Launching from Space Launch Complex 40 (SLC-40) on the Cape Canaveral Space Force Station, in Florida, the Starlink Group 5-9 mission will mark SpaceX’s fourth launch in May.
Starlink Group 5-9 can be 2023’s 69th orbital launch attempt; with 4 missions failing to achieve orbit, SpaceX currently makes up just below 50% of all successful orbital launches this 12 months.
On May 11 the Space Launch Delta 45’s weather squadron released a launch mission execution forecast for this mission, giving the weather a 95% probability of supporting the launch. The one concern is the cumulus cloud rule, which states that a launch cannot occur inside 18.5 km of cumulus clouds with tops that reach into freezing temperatures. Within the event of a delay, there may be a backup launch opportunity open on May 15, roughly 24 hours later.
The booster supporting this mission is B1067-11, which has previously supported CRS-22, Crew-3, Turksat-5B, Crew-4, CRS-25, Hotbird-13G, O3b mPOWER 1&2, and three Starlink missions. After stage separation, B1067 will attempt landing atop Just Read the Instructions (JRTI), which is stationed ~660 km downrange within the Atlantic Ocean. The autonomous spaceport drone ship was tugged downrange by Crosby Skipper. SpaceX’s multi-purpose recovery vessel Bob can be providing support to the drone ship and can recuperate the fairings from the water.
Overall, this mission will mark SpaceX’s a hundred and twenty fifth launch from SLC-40, 223rd Falcon 9 launch, one hundred and sixty fifth reflight of a booster, 191st booster landing, and 117th consecutive booster landing. The last booster landing failure was on Starlink v1.0 L19 on Feb. 16, 2021, when a hole within the engine boot led to engine shutdown during descent, resulting in the booster crashing within the Atlantic Ocean.
Atop the Falcon 9 in its payload fairing is 56 Starlink v1.5 communication satellites. These satellites can be placed into an initial LEO of 298 by 340 km at 43.00 degrees. The satellites will then spend the approaching months raising this orbit right into a Starlink generation two shell: a 530 km circular shell inclined at 43 degrees.
The familiar launch sequence of the Falcon 9 will start at T-38 minutes when the launch director will confirm that teams are go for propellant load. Three minutes later, each stages will begin being fueled with chilled RP-1 (a refined type of kerosine) and the primary stage will begin being crammed with super-chilled liquid oxygen (LOX).
Departure! Just Read the Instructions droneship is outbound to support the Starlink 5-9 mission. Tug Crosby Skipper is towing.
B1069 within the background. Via https://t.co/icguJj64A8 pic.twitter.com/GRbEQVLpzO
— Gav Cornwell (@SpaceOffshore) May 10, 2023
Fueling on the second stage can be wrapped up at T-20 minutes when SpaceX will purge the lines of the transporter erector to organize for second stage LOX filling. It will start at T-16 minutes.
At T-7 minutes, the primary stage will flow a small amount of LOX through the turbo pump of the Merlin 1D engines to chill it down ahead of full propellant flow at engine ignition. Doing so ensures that when full propellant flow starts at engine ignition, the propellants won’t boil immediately, making a gas bubble that may damage the engine’s turbines; in extreme cases, this can lead to an engine exploding.
At T-1 minute, the vehicle will enter startup. Presently control of the countdown is handed over to the vehicle. Humans are in a position to call aborts up until T-10 seconds, after which all aborts should be handled by the vehicle itself.
Three seconds before liftoff, the vehicle will command ignition of all nine M1D engines. By T-0.2 seconds the engines can be at full power, and the vehicle will check the health of all of the engines. If all engines and the vehicle are nominal, the hydraulic launch clamps will release, letting the vehicle lift off.
The primary stage will burn for 2 minutes and 28 seconds before shutting down and separating from the second stage. At this point, the primary stage will perform its entry and landing burns, landing on JRTI. Shortly after stage separation, the payload fairings can be deployed from the Falcon 9 second stage, which can then use cold gas thrusters and parachutes to softly splash down within the Atlantic Ocean for recovery.
Fairing reentry on the ViaSat-3 mission was the most well liked and fastest we have ever attempted. The fairings re-entered the atmosphere greater than 15x the speed of sound, making a large trail of plasma in its wake pic.twitter.com/VgdlH6r3yR
— SpaceX (@SpaceX) May 2, 2023
Stage two will burn for just below six minutes before cutting off at T+8:36. At this point the stage will coast for ~45 minutes, before igniting again for lower than two seconds. After the second engine cutoff, the stage will begin to rotate end-over-end before deploying the 4 tension rods at T+1:04:53.
The second stage will then coast for some time longer, before igniting for a deorbit burn, causing the stage to reenter just south of Cape Town, in South Africa.
SpaceX has plenty of other launches planned for the remainder of this month, including Starlink Group 6-3, Iridium-9 & OneWeb flight 19, Axiom Mission 2, and Arabsat 7B next week. The week after that, SpaceX is predicted to conduct several more Starlink flights.