It looks like they had a successful suborbital test of SARGE today at Spaceport America (after the earlier successful launch of Crew Dragon early this morning).
[Tuesday noon update]
Russ Blink just posted an explanation of the wobble at Arocket:
The wind picked up as we approached launch and the torque due to the fins at liftoff was getting pretty high, that caused the initial pitch angle and the control PID is pretty close to critically damped, which of course needs to be addressed, however it settled down nicely until we hit a high wind shear which it damped out slowly again after passing through. Still she was heavily influenced by the wind which we are addressing.
The fins on this flight were actually hurting us because of weather-cocking. We intend to remove or reduce them in the future when we have good aero data or modeling to tune the control part of our gnc for that condition.
For those curious in comments…
[Bumped]
Was it just the camera work, or did the rocket wobble coming off the pad? They had a similar wobble on their pathfinder launch last year.
I’m pretty sure it was the rocket. Ignition is at 1:21:54, and it didn’t seem to stabilize until 1:22:01.
Maybe insufficient control authority from gimbals (if they have them) and couldn’t stabilize until the fins could catch enough air.
The text accompanying this video adresses the wobble during the last flight. Presumably the cause this time was different.
https://www.youtube.com/watch?v=AA_tsUOD1gA&app=desktop
Thanks for the link. I think the issue may still be interaction with the launch stool, even if it wasn’t exactly the same problem as the pathfinder mission’s loadcell stool set up.
Is it just me, or does Spaceport America look a little…sparse? 🙂
In any case, big kudos to EXOS Aerospace. Rocket science continues to prove that it is, actually, rocket science and not particularly easy.
What did sounding rockets do before this? Lawn Dart? parachute?
What sort of damage did they take and what sort of damage to they expect from this parasail? I expect some fin damage perhaps.
Sarge recovery:
https://www.youtube.com/watch?v=1xHjbLIeqSo
I saw that.
What I was asking was what did sounding rockets do before SARGE and how much damage did they take?
Rapid scheduled disassembly.
Congratulations to the team. Great job. Some launch stability issues to work but hey that’s what makes it fun and worthwhile…
i was left thinking about variable geometry fins?
Thanks for passing along the update, Rand. To many, I’m sure the test didn’t look like much, and certainly others are much more advanced. However, a flight test answers questions faster than theoretical analysis. Anomalies like that are great learning opportunities as they provide a wealth of information.
The rocket is small enough to use a mobile launcher mounted on the back of a good sized truck. By having the launch truck drive with the wind during launch so that the driver’s cigar smoke keeps pace with his open window, the wobble can be completely eliminated.
For those who might wonder about the method, just tell them the aeronautical reason that the guy driving the launch truck as the rocket takes off is always smoking a cigar. It’s not just to look cool.