Article SpaceX’s unmatched streak of perfection with the Falcon 9 rocket is over

[C C]

https://arstechnica.com/space/2024/07/th...t-is-over/

EXCERPTS: A SpaceX Falcon 9 rocket suffered an upper stage engine failure and deployed a batch of Starlink Internet satellites into a perilously low orbit after launch from California Thursday night, the first blemish on the workhorse launcher's record in more than 300 missions since 2016.

Elon Musk, SpaceX's founder and CEO, posted on X that the rocket's upper stage engine failed when it attempted to reignite nearly an hour after the Falcon 9 lifted off from Vandenberg Space Force Base, California, at 7:35 pm PDT (02:35 UTC).

[...] While ground controllers scramble to salvage the 20 Starlink satellites, SpaceX engineers began probing what went wrong with the second stage's M-Vac engine. For SpaceX and its customers, the investigation into the rocket malfunction is likely the more pressing matter.

SpaceX could absorb the loss of 20 Starlink satellites relatively easily. The company's satellite assembly line can produce 20 Starlink spacecraft in a few days. But the Falcon 9 rocket's dependability and high flight rate have made it a workhorse for NASA, the US military, and the wider space industry. An investigation will probably delay several upcoming SpaceX flights.

[...] The Federal Aviation Administration, which licenses all commercial space launches in the United States, will require SpaceX to conduct a mishap investigation before resuming Falcon 9 flights... (MORE - missing details)

[Yazata]

Watching the livestream of the launch, it quickly became apparent that there was unusual ice buildup on the second stage Merlin vacuum engine. Pretty clearly there was a leak.

But the engine kept working on the stage's first burn-to-orbit. Unfortunately, when time came for the stage's second orbit-adjustment burn intended to deliver the Starlinks to their proper orbit, the MVac engine blew up.

https://x.com/NASASpaceflight/Status/181...8520588583

[Yazata]

SpaceX says:

https://www.spacex.com/updates/#falcon-9...-to-flight

FALCON 9 RETURNS TO FLIGHT

SpaceX submitted its mishap report to the Federal Aviation Administration (FAA) regarding Falcon 9’s launch anomaly on July 11, 2024. SpaceX’s investigation team, with oversight from the FAA, was able to identify the most probable cause of the mishap and associated corrective actions to ensure the success of future missions.

Post-flight data reviews confirmed Falcon 9’s first stage booster performed nominally through ascent, stage separation, and a successful droneship landing. During the first burn of Falcon 9’s second stage engine, a liquid oxygen leak developed within the insulation around the upper stage engine. The cause of the leak was identified as a crack in a sense line for a pressure sensor attached to the vehicle’s oxygen system. This line cracked due to fatigue caused by high loading from engine vibration and looseness in the clamp that normally constrains the line. Despite the leak, the second stage engine continued to operate through the duration of its first burn, and completed its engine shutdown, where it entered the coast phase of the mission in the intended elliptical parking orbit.

A second burn of the upper stage engine was planned to circularize the orbit ahead of satellite deployment. However, the liquid oxygen leak on the upper stage led to the excessive cooling of engine components, most importantly those associated with delivery of ignition fluid to the engine. As a result, the engine experienced a hard start rather than a controlled burn, which damaged the engine hardware and caused the upper stage to subsequently lose attitude control. Even so, the second stage continued to operate as designed, deploying the Starlink satellites and successfully completing stage passivation, a process of venting down stored energy on the stage, which occurs at the conclusion of every Falcon mission.

Following deployment, the Starlink team made contact with 10 of the satellites to send early burn commands in an attempt to raise their altitude. Unfortunately, the satellites were in an enormously high-drag environment with a very low perigee of only 135 km above the Earth. As a result, all 20 Starlink satellites from this launch re-entered the Earth’s atmosphere. By design, Starlink satellites fully demise upon reentry, posing no threat to public safety. To-date, no debris has been reported after the successful deorbit of Starlink satellites.

SpaceX engineering teams have performed a comprehensive and thorough review of all SpaceX vehicles and ground systems to ensure we are putting our best foot forward as we return to flight. For near term Falcon launches, the failed sense line and sensor on the second stage engine will be removed. The sensor is not used by the flight safety system and can be covered by alternate sensors already present on the engine. The design change has been tested at SpaceX’s rocket development facility in McGregor, Texas, with enhanced qualification analysis and oversight by the FAA and involvement from the SpaceX investigation team. An additional qualification review, inspection, and scrub of all sense lines and clamps on the active booster fleet led to a proactive replacement in select locations.

Safety and reliability are at the core of SpaceX’s operations. It would not have been possible to achieve our current cadence without this focus, and thanks to the pace we’ve been able to launch, we’re able to gather unprecedented levels of flight data and are poised to rapidly return to flight, safely and with increased reliability. Our missions are of critical importance – safely carrying astronauts, customer payloads, and thousands of Starlink satellites to orbit – and they rely on the Falcon family of rockets being one of the most reliable in the world. We thank the FAA and our customers for their ongoing work and support.

[Yazata]

Falcon is back!

B1069 flew for the 17th time, successfully delivering 23 Starlinks to orbit. Launch was from Pad 39A at KSC and landing was on JRTI.

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SpaceX has two more Falcon 9 launches planned this weekend, one from CCSFS, the other from Vandenberg SFB, as they try to clear up the backlog of launches that would have gone during the last two weeks.

https://arstechnica.com/space/2024/07/sp...t-anomaly/

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And B1077 just launched 23 more Starlinks from SLC 40 at CCSFS. Landing was on ASOG

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[Yazata]

And B1071 departed Vandenberg Space Force Base in California before dawn this morning, successfully putting 21 Starlinks into orbit before landing on OCISLY. This was 1071's 17th flight.

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