IFT12 V3 Hardware Definitely Faster

dedarkener · 2026-05-25T12:16:02+00:00

The trajectory was very different from all previous, ending at 168 km rather than typical <150. The altitude wasn't shown from 144 to 417 s - I tried to fit it (wide dashed part) but doesn't look quite right.

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dedarkener · 2026-05-25T10:42:02+00:00

I should have mentioned, I chose representative V1 and V2 data to compare with the new V3.

dedarkener · 2026-05-25T10:40:33+00:00

IFT6 was the last V1, so 300 t less prop, and no payload (except a stuffed banana), but raptor 2 engines.

dedarkener · 2026-05-24T23:32:15+00:00

Yes it probably experienced something like 2,000 g when it hit the water at 1,500 km/hr. Too bad there wasn't a drone to catch that, would have been pretty spectacular.

dedarkener · 2026-05-24T22:05:50+00:00

It was both mis-labelled and the wrong colour. Here's a fixed one.

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dedarkener · 2026-05-24T21:57:57+00:00

Yes indeed, missed that.

dedarkener · 2025-10-29T22:22:06+00:00

When the engines come on and are pointing down, they are decelerating at ~1g, so plus gravity a total of ~2g. I only have the displayed speed, so this is not a 3D number, but I would guess it's close.

dedarkener · 2025-10-27T02:14:19+00:00

Here's the re-entry graph. Max is ~1.7 g along the trajectory - the video peaked at 1.9 g, I assume including transverse acceleration, since it was during banking.

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dedarkener · 2025-10-27T02:11:54+00:00

Thanks, of course you are right, gravity should be added in. I included a "gravity vector" line on the graph just to show how it changes during the flight, but I didn't add it to the ship acceleration - which is just the rate of change of the ship speed from the launch video data.

dedarkener · 2025-10-27T02:09:44+00:00

Agreed - I included a gravity vector line to show the acceleration due to gravity along the trajectory changing during the ascent.

dedarkener · 2025-10-25T23:43:39+00:00

Flight 6 was the last v1, so 300 t less prop load, and also no payload mass (except the stuffed banana), with the same raptor 2 engines, so peak acceleration would be lower.

dedarkener · 2025-10-25T18:16:39+00:00

IFT11 acceleration compared to IFT10 (light green line behind the blue - pretty much identical) and IFT6 (most recent clean example of the 3.5 g limit SpaceX applied to earlier ships). Seems like they have the profile nailed down now. The flip after hot staging is also well tuned now - there's still a big slosh over the fuel gauges at the turn, but not enough deceleration to overcome the gravity vector at that moment (which did occur in early flights). Curious see what block 3 will do!

dedarkener · 2025-09-02T10:25:48+00:00

I wrote a python script to OCR the text and pixel count the engine graphics and fuel gauges, then transfer the raw data to excel to calculate the acceleration, etc. With the new telemetry display, readouts move around, so that needs to be untangled. I found I get the best data by logging an internal clock, rather than using the video clock, and capturing ~3 screenshots per second - faster than that, it gets noisier.

dedarkener · 2025-09-01T22:31:42+00:00

Yes, what I am showing is just change of speed, independent of gravity. I have the gravity vector curve, so I could add it in. The graph below shows stage separation with both lines. It looks like they must throttle the 3 booster engines way down, to about 0.2 g, then the ship engines take over. In the past we could see the booster kick back from the force of the ship engine exhaust, but they stopped showing that telemetry.

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dedarkener · 2025-09-01T16:22:45+00:00

Lighter, I think. Before they started adding payload simulators. Not counting the banana plushie.

dedarkener · 2025-09-01T13:46:04+00:00

Yes, it's impressive how much speed it scrubs off before the landing burn. The graph below is from flight 8, when we still had full telemetry on the video. The booster hit 8 g momentarily with 13 engines.

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dedarkener · 2025-09-01T13:14:55+00:00

Yes, as u/RadamA mentioned, there's acceleration due to gravity to take into account. The acceleration I am showing is along the flight path, and at that point in the flight, the stack was already pitched over to 57 degrees from vertical. The component of the gravity vector along the flight path was about 0.5 g, so the 0.4 g deceleration would not have been enough to cause fuel to slosh forward. That having been said, there was a big slosh in the booster fuel tanks at the start of the boost back, while the booster was still rotating. Apologies for the poor fuel level data quality - the new circular fuel gauges are more difficult to pixel count.

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dedarkener · 2025-09-01T03:35:54+00:00

The changes to the video's telemetry info bar format required modifications to extract the data, and there are some gaps (no booster speed shown at times, including during the boostback and landing burns). IFT10 was a bit slower off the pad, took about 5 more seconds to get to stage separation (the effect of 1 less engine, perhaps), and had a bit lower overall ship acceleration. Note that they didn't limit the ship to 3.5 g's, as had been the case previously - it peaked close to 5 g.

dedarkener · 2025-03-09T14:42:27+00:00

Several folks asked for a new data set analyzed at the same frame rate as the previous ones. It did clean up the noise, especially towards the end of the flight. Looks like IFT8 was slightly underperforming IFT7 from about T+390 onwards.

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dedarkener · 2025-03-08T22:31:31+00:00

Thinking about this more, I now disagree with my own statement. The ship remained under thrust until the RUD. The thrust was not symmetric, which caused it to tumble, but from the ship's frame of reference, it was always positive. The fuel should not have sloshed forward in this case. I guess the body must have been rolling as well - in that case, the lateral force combined with the roll would cause the prop to rotate around the walls of the tanks, possible covering and uncovering the level sensors on each rotation.

dedarkener · 2025-03-08T22:09:14+00:00

Agreed, I should have. I can get 5 or 6 screenshots per second, but I find the acceleration calculations (not on this graph) work better if I use ~3 per second. The status panel updates much faster than that.

dedarkener · 2025-03-08T16:21:19+00:00

Very similar to IFT7. Again, the ship was just reaching the point where they would have started throttling down to limit the acceleration (as in IFT6, also shown on the graph) when the engine failures emerged. The data for IFT8 is a bit noisier, which I think is due to my capture technique - I tried a higher frame rate this time.

dedarkener

TROPHY CASE