Nearly every rocket that has flown has had some sort of malfunction, and because thousands of parts all need to work in perfect harmony to complete a mission successfully, every once in a while there’s just going to be one part that just doesn’t work.
Witnessing an anomaly during a space flight may not seem that unusual, but as flights become more frequent, it is becoming more unusual. It’s almost expected that the first launch of a new rocket will end up failing at some point during flight. But when a rocket that has been flying smoothly at high speed for more than seven years is no longer able to deliver its payload, the spaceflight community takes notice.
At 10:35 PM EDT on Thursday, July 11 (2:35 AM EDT on Friday, July 12), the Falcon 9 was grounded after a malfunction in its upper stage caused its Merlin Vacuum (MVac) engine to shut down. The anomaly also resulted in the loss of its onboard Starlink satellites, which were unable to reach a stable orbit.
The Falcon 9 is an extremely reliable launch vehicle that has only experienced four malfunctions to date. Most of those failures occurred during the early stages of the design of the Block 2 and Block 3 rockets. The Falcon 9 Block 5 has completed 297 successful launches up until its 298th launch on Saturday, making it one of the most reliable rockets ever flown.
The unusual history of the Falcon 9
The first in-flight failure for the Falcon 9 occurred on June 28, 2015. Following a normal launch of a Falcon 9 Block 2 on the CRS-7 mission, the second stage’s liquid oxygen (LOX) tank overpressurized and ruptured 139 seconds into the flight. The tank rupture destroyed the rocket 11 seconds later. The mission was to use SpaceX’s unmanned Dragon capsule to resupply the International Space Station, but the capsule separated from the rocket and crashed into the ocean, becoming lost.
CRS-7 launch. (Credit: NASA/Charles Babir)
The failure of the vehicle and its payload led NASA to step in to investigate, and it was discovered that a strut inside the second stage LOX tank was unable to withstand the forces it was meant to withstand. SpaceX fixed the issue by replacing the failed strut. The failure was averted by developing a more robust version and mandating further audits of the aircraft’s quality before flight. After the failure, the Falcon 9’s success rate was 95 percent, and it was about six months before its next mission, which was scheduled to fly on December 21, 2015.
After the failure of CRS-7, normal launches resumed and SpaceX’s landings began to be successful. The first successful landing of an orbital rocket occurred on the next launch, when Booster B1019 landed on SpaceX’s Landing Zone 1. Then, in the four launches since the failure, the first successful booster landing was on a drone ship. Of course I still love you OccurredBy September 1, 2016, SpaceX had achieved many more successful launches and landings.
Nine months after CRS-7, the Falcon 9 encountered another anomaly. AMOS-6 was scheduled to be SpaceX’s 29th Falcon 9 launch. During propellant loading for pre-flight static firing testing, a liner in the Composite Overwrapped Pressure Vessel (COPV) tank bent, causing propellant to collect under the liner and spark due to friction. This caused an explosion and destroyed the entire vehicle. The AMOS-6 anomaly reduced the Falcon 9’s reliability to less than 90%. On January 14, 2017, SpaceX resumed flight just four months after AMOS-6.
AMOS-6 static fire anomaly. (Credit: SpaceX)
Recent anomalies in the spaceflight industry.
During the early stages of development of a new rocket or a new iteration of an operational rocket, it is almost expected that something will go wrong. Many startups and even government agencies experience failures during the first few launches of a new system. SpaceX has begun to adopt a “fail fast, iterate faster” approach to rapidly accelerate their designs. No rocket has embraced this philosophy more than SpaceX’s rockets. Starship.
All of Starship’s test flights, from Starhopper to high-altitude suborbital flights to today’s near-orbit flights, have been conducted at a rapid pace. For example, it took the team five attempts to learn how to land the ship. But as flight tests have progressed, SpaceX has learned from failure and rapidly improved the vehicle in ways that could never have been predicted from blueprints alone. Today, Starship is not a reliable vehicle, but with each integrated flight test, many of the system’s requirements are completed, and SpaceX’s goals are increasingly met. It may not be long before Starship is considered a reliable satellite launch vehicle.
Starship’s first flight. (Photo by NSF’s Max Evans)
There are many examples of emerging space companies taking on rocket development and becoming successful profitable aerospace companies. One company currently on that journey is Firefly Aerospace with its Alpha rocket. Alpha has completed five flights, but it hasn’t had the best track record – there was a failure on the first flight, partial failures on the second and fourth flights, and two successes on the third and fifth flights. Building on its recent successes, Firefly is on track for another clean launch later this year in October. If all goes well, Firefly may already be past an inflection point of success.
The European Space Agency (ESA) is the government agency that built and launched the newest rocket, the Ariane 6. The first flight of Ariane 6 went without a hitch until the first hour and 14 minutes of the flight. Ariane 6 successfully circularized orbit and deployed most of its 11 onboard payloads. Then the Auxiliary Propulsion System (APU) failed, causing the planned third deorbit burn to fail. Even after years and billions of dollars of development, one small anomaly can often cause an entire mission to partially fail.
Ariane 6 maiden launch (Courtesy of ESA)
Another government One organization that overcame this problem and ultimately succeeded is the Japan Aerospace Exploration Agency (JAXA), the Japanese space agency. The organization had several issues with its new H3 rocket, which debuted last year. After the first test flight of TF1 in March 2023 failed due to a failure of the second stage engine to ignite, JAXA had just under a full year to prepare the next flight of H3. On its second flight, H3 successfully reached its planned sun-synchronous orbit and deployed the satellite. And just four months later, the first-ever designated flight was a complete success.
Rocket Lab is following a similar path to the other private companies mentioned above. Rocket Lab’s first flight of the Electron survived stage and fairing separation without incident. However, a software failure that caused a loss of telemetry feeds triggered the flight termination system and ended the mission. After this launch, Electron flew safely through its 13th flight, which failed during the second stage burn when a wiring fault killed the electrical connection to the engine’s turbopumps.
Visible sparks at the point where an anomaly occurred during Rocket Lab’s 41st launch. (Courtesy of Rocket Lab)
Then, on Electron’s 20th mission, an ignition failure caused the second stage to shut down early. The ignition failure caused the thrust vector control system to malfunction, sending the rocket off its planned orbit. Twenty more missions flew without incident until Electron’s 41st mission. The Electron failed to reach orbit due to an arcing short, causing the upper stage’s Rutherford engine to lose thrust. After this failure, it took Rocket Lab just under three months to get the Electron back in the air. Rocket Lab has now conducted 50 launches with a 92 percent success rate.
Blue Origin’s New Shepard suborbital rocket has been successfully launched 24 times. However, during the NS-23 mission, the BE-3 main engine, which powered the capsule’s launch escape system, failed. Blue Origin’s booster Tail 3, It was on its ninth flight. New Shepard structurally failed due to a temperature rise in the BE-3PM engine, which was not accounted for in the booster. Fortunately, there was no crew on the capsule, only commercial payloads. The launch escape system worked as intended, and the payload returned safely to Earth. New Shepard achieved a 96 percent success rate in 25 missions, with only one malfunction. It took more than 15 months for New Shepard to resume flight after NS-23 shut down Blue Origin operations.
Anomaly on New Shepard during mission NS-23. (Credit: Blue Origin)
Falcon 9 resumes flying
The Falcon 9 will return from a short hiatus with the Starlink Group 10-4 mission. The launch is scheduled for 12:13 a.m. EDT (4:13 UTC) on Saturday, July 27, from SLC-40 at Cape Canaveral Space Command Station. The FAA announced on July 25 that the anomaly did not pose a public safety issue. While this doesn’t mean the investigation is over, it does mean that SpaceX can resume Falcon 9 launches.
SpaceX revealed that the problem was likely caused by a crack that occurred in the “sense line” during the first burn of the second stage. The sense line is responsible for checking the pressure of the second stage LOX tank. When the second stage burn began, the MVac engine was flooded with cryogenic LOX, which overcooled it and overpressurized the engine. This likely led to an explosion, which ended the burn and caused a loss of attitude control. SpaceX said that the sensor connected to the sense line is not used in the flight safety system and that the sensor is no longer needed by other systems. Therefore, SpaceX plans to remove the faulty sense line and sensor from the vehicle in the future.
The pace of the launch has allowed us to collect an unprecedented level of flight data, and we are ready to resume flight as soon as Saturday, July 27th. https://t.co/DvO0z1NbUm
— SpaceX (@SpaceX) July 25, 2024
That SpaceX was able to recover the Falcon 9 within 14 days of the second stage failure is remarkable in itself. With 355 missions in 14 years of operation and only four malfunctions, the Falcon 9 boasts a 99 percent success rate, making it one of the most reliable rockets ever flown.
(Main image: Falcon 9 launching from SLC-40 at Cape Canaveral Space Force Station. Courtesy of NSF’s Max Evans)
