Understand Starship's "Tenth Flight" at a Glance: Spaceship Achieved "Crucial Leap" without "Chopsticks" to Catch Rocket

Starship takes a big step forward.

Elon Musk is still chasing the dream of colonizing Mars.

At Beijing time on August 27, the tenth integrated flight test of Starship (hereinafter referred to as "the tenth flight") was successfully carried out. The flight test was originally scheduled for August 25 but was postponed for two days due to ground system failures and weather conditions.

This flight was executed by the combination of the second - generation Starship S37 and the B16 booster. In addition to testing the performance and reliability of the spacecraft and the booster, one of the important highlights of Starship's "tenth flight" was to execute the deployment mission of the "Starlink satellite simulator", which was not completed in the previous launch due to failure.

It should be noted that this flight does not involve the recovery of the booster and the spacecraft.

Judging from the actual results, the booster successfully completed the test mission during the landing burn phase and splashed down in the Gulf of Mexico. The satellite simulator deployment of the second - stage spacecraft, the space ignition of the Raptor engine, the re - entry into the atmosphere, and the splashdown in the Indian Ocean were all successfully completed.

The "tenth flight" is the fourth flight test of Starship this year. The previous three tests ended in failure, and the tasks were quite similar. This is a typical feature of "rapid iterative verification". However, getting stuck on specific tasks in the previous tests also reflects the limitations of this approach - the model of locating problems through real - launch verification. In addition, the repeated testing and verification of the same - type tasks have continuously pushed up the launch cost.

Currently, the iteration rhythm of Starship far lags behind Musk's expected time to lead humanity into the vastness of space.

Moreover, the prerequisite for manned spaceflight is to ensure a highly stable and reliable repeated flight capability. Before that, a more fundamental condition is to at least ensure the capabilities of payload deployment and spacecraft recovery.

01 Highlights of Starship's "Tenth Flight": No Booster Recovery, Spacecraft Deploys "Satellites"

It is estimated that it will take 1 hour and 6 minutes from the launch of Starship's "tenth flight" to the splashdown of the S37 spacecraft in the Indian Ocean.

During the flight test, the S37 spacecraft will execute the payload deployment mission - releasing the "Starlink satellite simulator" (the simulated satellite is comparable in size to the next - generation Starlink satellites). The simulated satellite will fly in sub - orbit and burn up when re - entering the atmosphere. The spacecraft itself needs to collect reliability data of relevant components after improvements such as heat insulation and capture to prepare for a smooth return to the launch site in subsequent flights. After completing the data collection, it will splash down in the Indian Ocean.

Animated demonstration of Starship deploying satellites

The B16 booster is mainly used for flight limit tests, including collecting real - performance data under future flight profiles and non - standard operating conditions at the offshore landing site in the Gulf of Mexico.

1) Key Tasks of the S37 Spacecraft:

On - orbit test:

Deploy 8 simulated Starlink satellites (a task that was planned in the "seventh flight" but failed to be implemented due to various problems)

Plan for the second ignition of the "Raptor" engine (a task that was also in the "seventh flight", testing the reliability of the engine in extreme environments such as extremely low temperatures and oxygen - free conditions. Otherwise, the engine cannot be ignited, and it will be impossible to return from future landings on Mars or the Moon)

Re - entry and return experiment:

Remove a large number of heat shields to test the tolerance of vulnerable areas and simultaneously test the performance of multiple types of metal heat shields (ceramic heat shields are fragile and have high maintenance costs, and may be reduced or even completely replaced in the future)

Verify the thermal performance and structural limits of the functional "capture connectors" installed on the spacecraft

Verify the reliability of the optimized design scheme for the edges of the heat shields

When the dynamic pressure of the re - entry trajectory is at its maximum, test the structural limits of the trailing - edge flaps

Splash down in the Indian Ocean

2) Key Tasks of the B16 Super Heavy Booster:

Do not return to the launch site for "capture" (there is also no arrangement for the "chopsticks - catching - rocket" this time. The process of take - off, separation of the first and second stages, and booster recovery is relatively mature)

After stage separation, it will first be controlled to flip and then start the return boost burn (using the technology from the "ninth flight" to ensure that more propellant is allocated to the take - off stage to improve the carrying capacity)

During the landing burn, actively shut down 1 central engine. Test the ability of the standby engines in the middle ring to take over. At the end, only use 2 central engines to achieve hovering over the sea surface, and then shut down the engines and crash into the sea (verifying the effectiveness of the redundant design of the engine system and the reliability under non - standard operating modes. Otherwise, if one engine suddenly shuts down, the booster will fall, and this is also the key to reusable recovery)

02 The "S37 + B16" Starship Combination: Old Booster + New Spacecraft

The most intuitive scene of the Starship combination launch is the "chopsticks - catching - rocket" - the super heavy booster is captured by two mechanical arms on the launch tower during its return.

So far, SpaceX has completed three "chopsticks - catching - rocket" tests. The most recent one was during Starship's "eighth flight", when the B15 booster was successfully captured, but this booster was not reused in the "tenth flight" mission.

For Starship's "tenth flight" this time, SpaceX used a brand - new B16 booster (all 33 engines are new). The assembly of this booster started in late October last year and was optimized based on previous flight test data.

The B16 underwent a cryogenic test in February this year and completed a full - duration static fire test at the Starship base in Texas in June (igniting while fixed on the launch pad and operating at full power for 8 - 12 seconds) to simulate the take - off stage state of a real launch.

According to official information, the B16 booster is equipped with 33 second - generation Raptor engines, with a single - engine take - off thrust of up to 230 tons, and the total thrust of the 33 engines exceeds 7,500 tons.

Actual photo of the B16 super heavy booster

Compared with the success and glory of the super heavy booster's "chopsticks - catching - rocket", the launch mission of the spacecraft has not been so smooth. The Starlink satellite deployment and the second space ignition of the Raptor engine proposed in the "seventh flight" failed to be implemented due to spacecraft out - of - control and disintegration.

The "tenth flight" was originally planned to use the S36 + B16 combination, but the S36 spacecraft was damaged due to a fuel - loading failure on June 18.

After the test failure of the S36 spacecraft, SpaceX adjusted the combination of Starship's "tenth flight" to S37 + B16. The S37 spacecraft completed the loading of the "simulated Starlink satellites" on August 23 and was stacked with the B16 booster.

You see, these frequent problems have slowed down the iteration rhythm of Starship, so Musk's statement that "there will be three launches in the future, one every three to four weeks" cannot be fulfilled for the time being.

Regarding the frequent explosions of the spacecraft, some industry insiders believe that SpaceX has not solved the problem of the "separation - to - orbit" of the second stage, that is, the spacecraft part. After the separation of the two - stage rocket, it enters the hypersonic flight stage. At this time, it is still in the atmosphere, and the rocket will be under great aerodynamic pressure, which will cause vibration, possibly leading to fuel pipe rupture, screw breakage, etc.

Normally, this process should be simulated on a ground vibration table to find risk points and formulate solutions. However, the second stage of Starship is too large, and there is no vibration table that can carry it. So, they can only rely on luck with each launch. Now, it's the 10th launch, and the fact proves that there is no luck. So, we'll see if they turn back to build a vibration table.

The "S37 + B16" Starship combination

Finally, let's talk about the scale of Starship. The entire Starship combination is 123 meters tall and 9 meters in diameter, like a stainless - steel "giant". Its payload capacity is 100 - 150 tons. The booster is 71 meters tall, and its propellant capacity is 3,400 tons. According to the official estimated goal, the Starship spacecraft can carry 100 people for long - term interstellar flights, and it can also be used for satellite launches, lunar base construction, and point - to - point flight transportation on Earth.

03 The Glorious Booster and the Troubled Spacecraft

The "ninth flight" used the B14.2S35 combination, but failed to complete the rocket splashdown mission, and the spacecraft exploded and disintegrated.

SpaceX's official investigation report shows that the flight failures of the booster were mainly concentrated in the descent stage after the landing burn. In this stage, a much larger angle of attack was used than in previous flight missions, with a maximum angle of attack of about 17 degrees. This flight experiment aimed to collect data to explore the performance limits of the booster.

Schematic diagram of the angle of attack, the angle between the chord line and the relative wind

In other words, it is to reduce the engine fuel consumption through aerodynamic deceleration and collect data to optimize future designs.

However, when the booster reached the planned splashdown area, 13 engines were supposed to be restarted for the landing burn, but only 12 were successfully restarted. Subsequently, a violent energy release event was observed near the tail of the booster.

SpaceX speculates that the reason might be that the large - angle - of - attack flight caused the booster to bear more pressure than expected, resulting in the failure of the fuel structure. The mixing of methane and liquid oxygen then caused the S14.2 booster to catch fire and explode.

SpaceX's solution to this problem is relatively straightforward. Since the large angle of attack doesn't work, they will reduce it to minimize the possibility of structural failure.

As mentioned before, the booster seems glorious and smooth because of multiple "chopsticks - catching - rocket" operations, but there are more problems with the spacecraft part. In the document submitted by SpaceX to the FFC during the "eighth flight", it was said that if the mission went smoothly, the spacecraft recovery would be tested in the "ninth flight". However, as we can see, the thermal/structural performance of the functional "capture connectors" is just being tested in the "tenth flight".

Regarding the S35 spacecraft in the "ninth flight", it failed to deploy the simulated Starship satellites. The official explanation is that after the shutdown of the second - stage engine, the high pressure in the nose cone area and the planned nose cone exhaust operation together caused a serious attitude deviation, making the spacecraft automatically skip the payload deployment mission.

SpaceX also emphasized that the high pressure in the nose cone caused a failure of the payload bay door. Even if the spacecraft did not skip the deployment mission, it could not be completed.

In addition, the spacecraft subsequently corrected the attitude deviation, and the nose cone exhaust function was restarted. However, liquid methane entered the nose cone, causing the temperature of the sensors and controllers to drop. Then, automatic passivation commands were triggered, skipping the on - orbit burn step, and all the remaining propellants were discharged into space. It re - entered the Earth's atmosphere in an off - nominal attitude and then disintegrated.

Compared with the slightly uncertain conclusion about the B14.2 booster, SpaceX emphasizes that the most likely root cause of the S35 spacecraft failure can be traced back to the failure of the diffuser in the main fuel tank pressurization system. Engineers successfully reproduced the failure process by simulating flight conditions and redesigned the fuel diffuser to more effectively introduce pressurized gas into the main fuel tank and significantly reduce the stress on the diffuser structure.

Regarding the failure of the S36 spacecraft on the test stand, SpaceX explains that the most likely root cause of this accident has been determined to be: an undetected or insufficiently screened damage in a composite - wound pressure vessel in the Starship payload section. After the failure of this pressure vessel, it caused the failure of the spacecraft structure, which led to the mixing and ignition of the propellants.

The solutions for the pressure vessel failure include reducing the working pressure of the pressure vessels in future flight missions and adding additional inspection and verification tests before filling the spacecraft with active propellants.

04 High - Frequency Launches Not Yet Realized, Mars Colonization Plan Needs to Accelerate

Evolution demonstration diagram of the Starship spacecraft part

In recent launches, both SpaceX and Musk have emphasized that the launch frequency of Starship will be higher and higher in the future. The short - term goal is "three launches in the future, one every three to four weeks".

Musk once said that 25 Starship launches would be carried out in 2025. Other future landmark highlights include the return - capture test of the Starship spacecraft and the real deployment of Starlink satellites.

SpaceX also frequently mentions the repeated cycle of "failure - re - verification" in press releases, emphasizing that the improvement of Starship's capabilities cannot be achieved overnight, but flight tests continuously provide valuable experience for the design of the next - generation Starship and the "Super Heavy" booster.

In addition, SpaceX also revealed that with the continuous improvement of the production capacity of the "Starfactory" at the Starship base and the continuous construction of new launch and test infrastructure in Texas and Florida,