Was the third flight of SpaceX Starship a success or a failure?

At 8:25 a.m. Central Time on the 14th (21:25 Beijing Time), SpaceX (Space Exploration Technologies Corporation) conducted the third test launch of its new generation heavy-lift rocket "Starship". After the rocket was launched from the base in Boca Chica, Texas, the work went smoothly. Space X founder Musk also posted on social media to congratulate Starship for "reaching orbital speed". However, during the re-entry into the atmosphere, the signal with the ground was lost for nearly 14 minutes, and the third test launch of Starship ended ahead of schedule . Was the third test launch, which attracted so much attention, a success or a failure?

Image source: SpaceX official website

01The total thrust exceeds 7,000 tons. How powerful is the starship?

Starship is a super-heavy space launch vehicle developed by SpaceX . It consists of a first-stage super-heavy booster and a second-stage starship spacecraft, and is called "Super Heavy-Starship", or simply "Starship".

The reason why Starship is so eye-catching is that it is the world's largest and most powerful launch vehicle to date. Starship is made of stainless steel welded throughout, and the overall shape is a cylinder with a diameter of 9 meters. Starship is 121 meters high, equivalent to a 40-story building; its takeoff mass is 5,000 tons, equivalent to the displacement of an entry-level destroyer. Such a takeoff mass is 1.6 times that of Saturn V, 1.8 times that of N1 rocket, 1.9 times that of SLS, 2.1 times that of Energia, 2.5 times that of space shuttle, and 5.7 times that of Long March 5.

In order to lift such a huge rocket into space, the super-heavy booster stage is equipped with a total of 33 "Raptor" liquid rocket engines, with a total thrust of nearly 7,600 tons, enough to lift the Eiffel Tower in France . This type of engine uses liquid oxygen/methane as propellant, and the specific impulse reaches 327s. These engines are divided into two circles and installed at the bottom of the booster stage. The outer circle of 20 engines is fixed, and the inner circle of 13 engines can swing 15 degrees in both directions for thrust vector control, and can adjust the thrust between 20% and 100%.

A photo from the launch tower's perspective of the third flight of the Starship, with all 33 engines of the first stage ignited and launched into space.

Image source: SpaceX official website

02Good news! It didn’t explode this time! Bad news: Maybe it failed again…?

SpaceX has high hopes for this test launch, and deliberately chose March 14, 2024, the 22nd anniversary of SpaceX's founding, for the launch. Compared with the first two test launches in April and November 2023, is this third "early-ended" test launch mission a failure?

Whether it succeeds or fails depends on the mission goal setting of the Starship. In this mission, the super-heavy booster stage code-named B10 flew normally after ignition and takeoff. All Raptor engines were successfully started and maintained normal ignition status throughout the launch process. At the end of the first stage of work, while shutting down most of the Raptor engines on the super-heavy booster stage, the Starship ignited the six engines on the Starship spacecraft stage code-named S28, successfully achieving thermal separation between the first and second stages. After separation, the super-heavy booster stage successfully completed an attitude flip and a complete reverse thrust ignition, allowing the booster to fly to the scheduled landing point in the Gulf of Mexico. After the six engines of the Starship spacecraft worked for 351 seconds, the Starship entered the scheduled orbit with a perigee altitude of only 50 kilometers, completing the entire orbital entry phase for the first time. During the orbital glide phase, the Starship also successfully completed the payload hatch opening and closing test, as well as the propellant transfer test. It can be said that it has successfully completed the entire process from launch to orbit entry .

GIF source: SpaceX live broadcast

In this case, how did the mission end? When Starship's super-heavy booster stage attempted its first landing reverse thrust ignition, it only successfully ignited three engines, and two of them were immediately shut down. The booster stage lost attitude stability and then disintegrated at an altitude of about 462 meters above the sea surface. Starship's orbital stage also lost attitude stability at the end of its orbital glide, and the excessive rolling speed prevented the planned re-ignition of a single Raptor engine in orbit. Starship persisted until the re-entry phase, and the telemetry images sent back showed the hot flames generated by its friction with the atmosphere. At about 49 minutes into the mission, the signal sent back by Starship through Starlink was interrupted, and it should have disintegrated and been damaged in the atmosphere.

This test launch historically verified the overall capability of Starship to launch into orbit, but there is still a long way to go to verify its complete return landing and reuse capability. In view of this, the Federal Aviation Administration (FAA) defined the launch result as a "failure" in a statement issued afterwards according to the Level 4 failure standard, and asked SpaceX to investigate the failure.

03Soaring into the sky, what will the future hold?

SpaceX's interplanetary transport system concept was first proposed by Musk in 2012, aiming to build a fully reusable two-stage rocket system to send humans to Mars in the 2020s and 2030s. After many design and name evolutions, it finally emerged as the current "Super Heavy-Starship".

In addition, the original design goal of the Starship is to be fully reusable, with the super-heavy booster stage able to return to the launch tower for landing, and the Starship spacecraft stage able to return from Earth orbit and land vertically on the predetermined pad. The Starship's payload carrying capacity is 150 tons in low-Earth orbit, and can reach 250 tons if it is not reused. The Starship is also designed to be refueled in low-Earth orbit in order to travel to more distant destinations, such as geosynchronous orbit, the moon, Mars, etc.

Based on SpaceX's outstanding R&D capabilities and the huge carrying capacity of the Starship, the project has also received extensive support from the US government and military. NASA has invested up to $4 billion in the Starship project, hoping to use it to implement the Artemis program and allow Americans to return to the moon. According to the latest schedule, the launch date of the "Artemis-3" manned lunar mission has been postponed to September 2026. It can be said that every step of the current progress of the Starship is related to the future US moon landing and the realization of the longer-term Mars colonization goal . Although the three test launches have made considerable progress, the current state of the Starship is still a long way from this goal. To support the realization of the ultimate goal, the Starship must be able to operate at a high frequency, because whether it is landing on the moon or on Mars, a large number of Starships need to be launched and docked in low-Earth orbit to transfer propellants.

To achieve this goal, SpaceX is making full use of its expertise in large-scale rapid production and rapid testing and iteration. SpaceX has proposed to the FAA that it hopes to be allowed to launch at least nine Starship launches this year. The current production of Raptor engines has reached 7 units per week, and the manufacturing speed of Starship prototypes has reached one every 2 to 3 weeks. The second Starship launch pad has also started construction near the existing launch pad. With SpaceX's past performance, there is still great hope that the Starship will eventually catch up with the US's target node for landing on the moon or even on Mars as scheduled.

04Some Future Outlook

With the advancement of aerospace technology and the increasing demand for space transportation, fully reusable launch vehicles, such as Starship, will be an inevitable trend in the development of future launch vehicles. Although Starship has not yet been completed, the speed of technological breakthroughs demonstrated by its first three test launches has already shocked the world. Difficulties that were previously considered difficult to overcome, such as dozens of high-thrust rocket engines working at the same time, have been successfully proven to be technically feasible twice.

Excellent competitors are not enemies, but best friends. Inspired by SpaceX, a powerful rival, my country's launch vehicle research and production companies have also focused on reusable technology.

GIF source: CCTV News

It is understood that China has completed the vertical take-off and landing hovering test of reusable rockets , breaking through the key technologies of reusable rockets, and some private enterprises have also begun to carry out different degrees of reusable technology demonstration and verification. At this year's two sessions, it was reported that China is currently working hard to develop 4-meter and 5-meter reusable rockets, which are scheduled to fly for the first time in 2025 and 2026 respectively.

Space exploration is never achieved overnight, and every progress is a milestone. Today, my country has cultivated commercial aerospace as a new growth engine. I believe that in the future fully competitive market environment, high-quality resources from all aspects of society will be fully mobilized to jointly meet the challenges brought by the technological revolution and promote the rapid progress and growth of my country's aerospace industry.

Author: Yu Yuanhang, Senior Engineer, Beijing Institute of Aerospace Systems Engineering

Audit:

Liu Yong is China's space science ambassador, director of the Science Popularization Committee of the Chinese Society of Space Science, and researcher at the National Space Science Center of the Chinese Academy of Sciences.

Zhou Binghong, China's space science ambassador, researcher at the National Space Science Center of the Chinese Academy of Sciences

Produced by: Science Popularization China

Produced by: China Science and Technology Press Co., Ltd., China Science and Technology Publishing House (Beijing) Digital Media Co., Ltd.