It’s now been a few days since Starship’s fourth Integrated Flight Test and the company just released some ground footage of the booster’s landing. While short, it gives more details into the exact orientation, engine use, and even proximity to the intended landing site.
This comes in addition to more comments from Musk talking about the boosters landing burn and why they might try to catch it on the next attempt. Based on the time between launches going back to IFT-1, the 5th flight could be sooner than many think. Here I will go more in-depth into the new booster footage, the launch timeline, catching challenges, and more.
New Video
Earlier this morning SpaceX finally showed off some footage from additional angles of the booster landing in the Gulf of Mexico. It starts with what looks like a view from the air and then switches to possibly a buoy out at sea in the intended landing location. The booster comes in at an angle and lights its engines right as it enters the clouds which not only slows but helps orient the booster nearly perfectly vertically. Unfortunately, SpaceX cuts the video back to the onboard footage right as the booster makes contact with the water so we don’t get a view of it bobbing before eventually tipping over. Either way, the initial lead up and engine light showcase some of the exact goals SpaceX had with this mission and landing over the water.
SpaceX stressed before the launch that the fourth flight test turned their focus from achieving orbit to demonstrating the ability to return and reuse Starship and Super Heavy. Specifically, they were quoted saying, “The primary objectives will be executing a landing burn and soft splashdown in the Gulf of Mexico with the Super Heavy booster, and achieving a controlled entry of Starship.” With this in mind, initial video and comments suggest the booster’s landing attempt was just about perfect.
Focusing back on the video you can see some large flames likely related to the one engine that didn’t successfully relight for the landing burn. However, as designed, the other 12 Raptors were plenty to slow the stage for a soft landing. For reference, this landing process simulates an eventual flight profile that brings the booster back to the launch site and performs that exact burn just above the tower. As it slows down it lowers between the two chopstick arms which then close under the catch points on the booster.
It’s important to point out that while on the surface the recent booster splashdown is impressive, there are even more factors to consider on an actual catch attempt. For example, not only do obvious things like the speed and altitude of the stage matter, but much more precise factors like its exact rotation/orientation to positon catching points in line with the arms. Combine that with the fact that the entire launch complex is static with the exception of the chopsticks and it will be an incredibly difficult process.
Fortunately for SpaceX, they seem to be very close to trying. Another interesting detail about the footage is the fact that some of the camera angles for the most part look static. This would suggest that SpaceX landed the booster at basically the exact spot they had planned beforehand. Comments from Elon after the flight also supported this with him mentioning that the booster successfully landed at a precise location.
For an actual catch attempt, the precision needs to be feet if not even closer which lowers the margin of error. Landing on drone ships is one thing but being caught out of the air is another. Either way, this launch was a great step in that direction.
Looking at the footage one more time in conjunction with the onboard telemetry gives us even more details. The onboard view and data highlight that right before the booster ignites its engines it’s traveling around 1200 km/h and is within 1 km of the ground. It initially ignites all 13 engines before switching to just the innermost three as it passes through the clouds. Over the next 15 or so seconds the booster manages to reduce its speed from 1200 km/h to a low of 9 km/h right around the time of contact. This is quite impressive and supports even more ambitious plans in the near future.
The Next Flight
Initially, after the launch, Musk tweeted that he thought they should try and catch the booster on the next attempt. In addition, in an interview with Ellie In Space he was quoted saying, “I need to regroup with the team and confirm that there aren’t any other known issues, but I think given that the booster came to a precise location, came to a potentially zero velocity landing in the ocean, I think we should probably try to catch it with the tower arms on the next flight.”
Based on these comments, he seems serious about the attempt to the point where it very well could be a possibility. The concerns would be damaging the tower or nearby infrastructures however SpaceX is in the process of building another tower and likes to take the occasional risk. As far as when the next attempt could be, looking at the time between the past four launches, it might be very soon.
After Integrated Flight Test 1, it took 212 days of work, FAA approval, and preparation until the second launch in November. After that, it only took 117 days to launch a third time after the second attempt. Most recently, SpaceX managed to launch Starship again after only 84 days. In other words, they went from 212 days, to 117, to 84. In less than three months they were able to get ready to launch the worlds most powerful rocket. This mainly comes down to a more streamlined process with the FAA along with less prep needed from the company. Things like the water deluge system and initial damage requires quite a few repairs and time. At this point they just launch and the pad among other infrastructure is ready to go only days after.
In addition, when the flight goes basically exactly to plan, it makes the process with the FAA much simpler and as a result, quicker. With all this in mind, we could realistically see another launch within three months from now. As far as whether or not they will be able to improve from the 84 days it took on the last flight is not clear. If they do it will likely be not far off. Either way, before we know it SpaceX should be getting ready for a fifth flight attempt.
In a statement released by the company not long after the mission they said, “The fourth flight of Starship made major strides to bring us closer to a rapidly reusable future. Its accomplishments will provide data to drive improvements as we continue rapidly developing Starship into a fully reusable transportation system designed to carry crew and cargo to Earth orbit, the Moon, Mars and beyond. Congratulations to the entire SpaceX team on an inspired fourth flight test of Starship! And thank you to our customers, Cameron County, spaceflight fans, and the wider community for the continued support and encouragement” they said.
In preparation for this most recent flight, SpaceX made a decent number of changes and upgrades to help ensure it was successful. For example, in one statement, SpaceX highlighted that “To accomplish this, several software and hardware upgrades have been made to increase overall reliability and address lessons learned from Flight 3.” They went on to say, “The SpaceX team will also implement operational changes, including the jettison of the Super Heavy’s hot-stage following boostback to reduce booster mass for the final phase of flight.”
We know now that this jettisoning was successful and we could end up seeing it again. Besides that change, there were a few very important upgrades made related to specific problems that occurred on Flight 3. On that test, following stage separation, Super Heavy initiated its boostback burn, and all 13 engines ran successfully until six engines began shutting down, triggering a benign early boostback shutdown. SpaceX confirmed that the booster then continued to descend until attempting its landing burn, which commands the same 13 engines used during boostback to perform the planned final slowing for the rocket before a soft touchdown in the water, but the six engines that shut down early in the boostback burn were disabled from attempting the landing burn startup, leaving seven engines commanded to start up with two successfully reaching mainstage ignition. The booster had lower than expected landing burn thrust when contact was lost at approximately 462 meters in altitude over the Gulf of Mexico and just under seven minutes into the mission.
In a relevant statement, SpaceX said, “The most likely root cause for the early boostback burn shutdown was determined to be continued filter blockage where liquid oxygen is supplied to the engines, leading to a loss of inlet pressure in engine oxygen turbopumps.” As far as upgrades, they said, “Super Heavy boosters for Flight 4 and beyond will get additional hardware inside oxygen tanks to further improve propellant filtration capabilities. And utilizing data gathered from Super Heavy’s first landing burn attempt, additional hardware and software changes are being implemented to increase startup reliability of the Raptor engines in landing conditions.” Based on what we just saw these upgrades were a great addition.
Conclusion
SpaceX just released some new footage of the booster landing which helps highlight the precision and accuracy of this process. It went so well that they might even try to catch the booster during the next flight attempt. With Starship launches continually getting faster and faster, this could be very soon. We will have to wait and see how it progresses and the impact it has on the space industry.
I hope SpaceX can catch the booster in FT-5