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"We lost the flight late into the mission. I am incredibly sorry that we failed to deliver our customers satellites today. Rest assured we will find the issue, correct it and be back on the pad soon."
https://twitter.com/Peter_J_Beck/status/1279532331838009345
Space is hard.
https://twitter.com/Peter_J_Beck/status/1279532331838009345
Space is hard.
At the point where kick stage sep was supposed to occur there was no announcement, and nothing at the end of the webcast to indicate there were any issues. So...?
Actually the timing was right around the time of the battery hot swap. It definitely didn't get to orbit which is where the kick stage would separate. The video they were showing us shut off at 190 km in altitude and 13,680 km per hour in speed. Right around that time the telemetry (which still seemed to be working) showed the speed dropped off to a trickle and altitude continuing to gain from the upward momentum. Maybe a turbopump failure that wasn't from the batteries.
Here’s a screen cap a second before they shut off the speed/altitude display. The altitude had fallen from a peak of of about 194km to 166, while the webcast host is talking as if nothing bad had happened.
EA livecast play by play of the launch - and failure. Interesting to see his reaction to the failure:
Watched Scott’s stream of that launch and now realize that the speed slowed and then started increasing as the altitude decreased, something I had missed the first time. I hope Rocket Lab can identify the issue quickly and resume their amazing launch cadence.
OneSpeed at NSF have scrubbed telemetry data from the videos, and made graphs of flights 11 and 13, (not flight 12, because it was DARPA mission without S2 telemetry)
FAILURE: Electron - Flight 13 - Pics Or It Didn't Happen - July 4, 2020 21:19UTC
You can see that acceleration and altitude start to lag down compared to F11 near Rocket Lab's given four minutes mark (edit by me), but only slightly. The throttle down before lost of thrust looks similar both graphs and video as before hot-swap at F11. It looks like a battery problem but call-out "Battery Discharge Nominal" after lost of thrust would rule it out.
FAILURE: Electron - Flight 13 - Pics Or It Didn't Happen - July 4, 2020 21:19UTC
You can see that acceleration and altitude start to lag down compared to F11 near Rocket Lab's given four minutes mark (edit by me), but only slightly. The throttle down before lost of thrust looks similar both graphs and video as before hot-swap at F11. It looks like a battery problem but call-out "Battery Discharge Nominal" after lost of thrust would rule it out.
Why does the acceleration have so many jitters and not a smooth line? If you are burning propellant at a constant rate, then your acceleration should steadily and smoothly increase as the overall mass is reduced, which I would think should be a smooth line too.
How does the speed curve not reflect the acceleration jitters?
How does the speed curve not reflect the acceleration jitters?
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I know nothing about the source of that data, but the noisy telemetry is likely just function of the dynamic environment vs sample rate on non-averaged data. It’s not real with respect to the overall vehicle’s acceleration, at least not to the magnitude represented. For instance, an accelerometer alone can’t separate structural vibrations from [the acceleration from] engine thrust, so points on the vehicle may see local +/- accelerations based on the sum of the two.
A velocity analogy would be kids in a car throwing a ball between the front and the back seat while going down the freeway. If the car is going 75mph and the kids are throwing the ball at 5mph, someone on the side of the road would often see a ball moving at 70 or 80mph...but the average ball velocity would always be 75mph.
A velocity analogy would be kids in a car throwing a ball between the front and the back seat while going down the freeway. If the car is going 75mph and the kids are throwing the ball at 5mph, someone on the side of the road would often see a ball moving at 70 or 80mph...but the average ball velocity would always be 75mph.
Data is not official. Like I said, it is read from the video by script -frame by frame with Optical Character Recognition (ORC). Both SpaceX and Rocket Lab's stream telemetry seems to be raw data, with no round-up e.g. digits cut. And no filtering just lower frame rate. Method which OneSpeed uses to "derivate" acceleration from velocity seems to produce jitters. I guess he doesn't want to filter it either, and just show it raw as possible.
And "jitters" are in the velocity data (due digit cut and frame rate) it just doesn't show in velocity, due... you know physics... Further reading:
Noise and Vibration Analysis: Signal Analysis and Experimental Procedures written by Anders Brandt
Well it certainly was visually noticeable. I have no idea if that much roll was nominal or not.
If this mission successfully put the payload on the surface of Mars, intact, it will be an impressive accomplishment!
Rocket Lab update (Sorry no video):
"Rocket Lab to Resume Electron Launches in August
Long Beach, California. July 31, 2020 – Rocket Lab today announced that it has received approval from the Federal Aviation Administration (FAA) to resume launches this month after identifying an anomalous electrical connection as the cause of an in-flight failure on July 4, 2020.
...Rocket Lab’s AIB was able to confidently narrow the issue down to a single anomalous electrical connection. This connection was intermittently secure through flight, creating increasing resistance that caused heating and thermal expansion in the electrical component. This caused the surrounding potting compounds to liquefy, leading to the disconnection of the electrical system and subsequent engine shutdown..."
Rocket Lab to Resume Electron Launches in August | Rocket Lab
"Rocket Lab to Resume Electron Launches in August
Long Beach, California. July 31, 2020 – Rocket Lab today announced that it has received approval from the Federal Aviation Administration (FAA) to resume launches this month after identifying an anomalous electrical connection as the cause of an in-flight failure on July 4, 2020.
...Rocket Lab’s AIB was able to confidently narrow the issue down to a single anomalous electrical connection. This connection was intermittently secure through flight, creating increasing resistance that caused heating and thermal expansion in the electrical component. This caused the surrounding potting compounds to liquefy, leading to the disconnection of the electrical system and subsequent engine shutdown..."
Rocket Lab to Resume Electron Launches in August | Rocket Lab
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