Author Topic: FAILURE: Astra Rocket 3.3 – STP-27AD1 – Kodiak – August 28, 2021 (22:35 UTC)  (Read 55278 times)

Offline PM3

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This is

- Astra's 6th launch attempt
- Astra's second third orbital launch attempt. The first one on September 12, 2020 failed shortly after liftoff. The second on December 15, 2020 did not reach orbital velocity.
- First launch of Rocket 3.3, which is a stretched version of the prototype Rocket 3.0 / 3.1 / 3.2. Rocket 3.3 is Astra's first production rocket, with many more to be built and launched.

Rocket S/N:  LV0006
Payload:  STP-27AD1 = some launch environment measuring devices
Launch pad:  Kodiak (PSCA) LP 3B
« Last Edit: 08/28/2021 10:38 pm by PM3 »
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Offline PM3

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https://astra.com/news/stp-27ad1/

Quote
ASTRA ANNOUNCES MULTI-LAUNCH CONTRACT AND FIRST LAUNCH WITH DEPARTMENT OF DEFENSE
AUGUST 5, 2021

Space Force expected to fly demonstration launch no earlier than August 27th   
 
Alameda, CA. August 5, 2021. Astra Space, Inc. (“Astra”) (Nasdaq: ASTR), today announced a launch window beginning August 27, 2021 for its first commercial orbital launch with the United States Space Force. Following this launch, Astra is under contract to perform a second launch later this year.
 
“We are thrilled to partner with Astra on this mission and believe this showcases critical low-cost, mobile and responsive launch capability,” said Colonel Carlos Quinones, Director, Department of Defense Space Test Program. 
 
Space Force contracted the launch through the Defense Innovation Unit’s Other Transaction Agreement with Astra. Space Force will be launching a test payload for the Space Test Program (STP-27AD1).
 
“We’re excited to kick off a multi-launch campaign with the Space Force” said Chris Kemp, Founder, Chairman and CEO of Astra. “This orbital demonstration launch allows our team to verify numerous upgrades to our launch system.”
 
STP-27AD1 will be conducted from Astra’s Kodiak Spaceport, located at the Pacific Spaceport Complex in Kodiak, Alaska. The launch window will begin at 1:00PM PT, on Friday, August 27, 2021 and will be open through Saturday, September 11, 2021.

https://twitter.com/astra/status/1423425251858259968

Quote
Successful hot fire test ✅.

bit.ly/hot-fire-LV006

#AdAstra



Possible Astra launch windows?
https://twitter.com/spacetfrs/status/1427725713633857537?s=21

https://twitter.com/spacetfrs/status/1427729496866758663?s=21

https://twitter.com/kemp/status/1429188861964345349

Quote
@Astra just arrived in Alaska this week, and our red team has already deployed the launch system!

https://astra.com/news/on-the-ground-lv0006-static/

Quote
ON THE GROUND: LAUNCH VEHICLE 0006 STATIC TEST
AUGUST 20, 2021



“The hot fire test is the final test of the entire integrated launch system, where we get to test every single component of the rocket,” explains Chris Kemp, Astra’s Founder and CEO. “It allows us to make sure all of the upgrades work before we send the rocket into space.”

During this “dress rehearsal for launch,” the fully assembled vehicle is positioned on the ground while engines are fired at full thrust. The static test — or “hot fire test” as it is sometimes known — allows our team to ensure all mechanics and ground support systems are functioning as expected, ready for a successful launch.

The video above shows the hot fire test for Astra Launch Vehicle 0006 on August 4, 2021. There are three main stages to the hot fire testing process that you can see in the video:

Fire suppression system: Water is sprayed out of the flame deflectors to cool down the vehicle prior to thrust.
All engines go: Engines are fired at full thrust, for 8-10 seconds. Flames erupt from the rocket’s booster, turning water from the fire suppression system into steam.
Shutdown: Systems are shut down, measurements are taken and analyzed, and the rocket is prepared for next steps.

Make sure to catch the live stream for the launch of LV0006. The launch window opens August 27, 2021 and runs through September 11, 2021. Follow us on Twitter for the latest announcements and news.

The FAA has just issued a notification to airlines advising them of a possible rocket launch. This would be between 21:00 UTC on August 27th and 00:30 on August 28th
https://twitter.com/SpaceTfrs/status/1431067936937103362
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Offline PM3

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https://www.nasaspaceflight.com/2021/08/astra-third-orbital-attempt-lv0006/

Quote
Astra to make third orbital launch attempt with LV0006
written by Thomas Burghardt August 27, 2021

Continuing the iterative path toward reaching orbit, Astra is preparing for its third orbital launch attempt. The first Rocket 3.3 vehicle, designated LV0006, is scheduled to lift off within a launch window that opens on Friday, August 27 at 2:00 PM PDT (21:00 UTC), with launch opportunities continuing through September 11.

Offline trimeta

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Nitpick, should the description on that video link to the main Astra thread or this thread?

Offline Ken the Bin

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For reference, the notices that I posted in the Astra general topic.

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Live stream now live!
« Last Edit: 08/27/2021 08:05 pm by FutureSpaceTourist »

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https://twitter.com/nasaspaceflight/status/1431347766190612485

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Prop loading has begun on Astra's Rocket 3.3 (LV0006)

NSF/Astra is live: youtube.com/watch?v=TvGiEt…

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https://twitter.com/nasaspaceflight/status/1431355820755804164

Quote
Coming up on T-20 minutes to the Astra Rocket 3.3 (LV0006) launch from LP-3B at the Pacific Spaceport Complex in Kodiak, Alaska.

There will be a slight hold at T-20 mins for software configuration work.

➡️youtube.com/watch?v=TvGiEt…

Offline cpushack

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Reloading software for each of the 5 main stage engines, and the S2 Ether engine.

Neat to be able to hear the process on the countdown net.  Thanks to NSF

Online FutureSpaceTourist

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Countdown resumed, new T-0 at 45 mins past the hour 

nice views from cameras on 2nd stage
« Last Edit: 08/27/2021 09:26 pm by FutureSpaceTourist »

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Timeline

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Abort at T-0

Edit to add:

https://twitter.com/nasaspaceflight/status/1431372628053278723

Quote
Abort at T-0. Evaluating reycle.

youtube.com/watch?v=TvGiEt…
« Last Edit: 08/27/2021 09:47 pm by FutureSpaceTourist »

Offline RocketLover0119

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SCRUB!

Next attempt NET tomorrow.
« Last Edit: 08/27/2021 09:52 pm by RocketLover0119 »
"The Starship has landed"

Online edzieba

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In the terminal count, there was an interesting callout from the LD to the FSO, advising them to prepare to issue an 'option command' at T+164 (2m 44s into flight) calling out "an event". Going by the timeline that's just prior to MECO. AFTS is not armed and instead in shadow mode (FSO would not be inhibiting an on-board system, the FTS is fired by ground command) so something to listen out for on the next attempt.

Offline Welsh Dragon

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Maybe I've missed it in other thread, but I'm surprised nobody has commented yet on the quality of the stream hosting, great job by Thomas and the Astra crew. Calm, understated and to the point. A great job.

Offline Conexion Espacial

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In the terminal count, there was an interesting callout from the LD to the FSO, advising them to prepare to issue an 'option command' at T+164 (2m 44s into flight) calling out "an event". Going by the timeline that's just prior to MECO. AFTS is not armed and instead in shadow mode (FSO would not be inhibiting an on-board system, the FTS is fired by ground command) so something to listen out for on the next attempt.
You mean it is possible that the FTS could be activated from the ground after the separation of the second stage to maybe test the system?
I publish information in Spanish about space and rockets.
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Offline Conexion Espacial

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« Last Edit: 08/28/2021 03:04 pm by Conexion Espacial »
I publish information in Spanish about space and rockets.
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Offline Conexion Espacial

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« Last Edit: 08/28/2021 08:06 pm by Conexion Espacial »
I publish information in Spanish about space and rockets.
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Offline Conexion Espacial

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« Last Edit: 08/28/2021 08:52 pm by Conexion Espacial »
I publish information in Spanish about space and rockets.
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NSF is live!
« Last Edit: 08/28/2021 09:02 pm by FutureSpaceTourist »

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Explanation for yesterday’s abort: engines appeared to start-up a little slower than expected, so vehicle aborted. Today they’ve preconditioned the vehicle (in an earlier hold) which should resolve the issue for today’s attempt.

Edit to add:

https://twitter.com/nasaspaceflight/status/1431724835571474443

Quote
Astra has made some operational adjustments to counter yesterday's abort (slow engine ramp up), including a reconditioning hold earlier in today's count (thus the more to the right for the T-0).

T-55 mins.

➡️youtube.com/watch?v=O8Tdm7…
« Last Edit: 08/28/2021 09:06 pm by FutureSpaceTourist »

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https://twitter.com/nasaspaceflight/status/1431731140771999744

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Holding at T-30 mins for prop fill requirements.

➡️youtube.com/watch?v=O8Tdm7…

Offline RocketLover0119

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Re: Astra Rocket 3.3 – STP-27AD1 – Kodiak – August 28, 2021
« Reply #26 on: 08/28/2021 10:01 pm »
Count has resumed!

Counting down to 3:30 PM Pacific time.
« Last Edit: 08/28/2021 10:01 pm by RocketLover0119 »
"The Starship has landed"

Offline RocketLover0119

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Re: Astra Rocket 3.3 – STP-27AD1 – Kodiak – August 28, 2021
« Reply #27 on: 08/28/2021 10:15 pm »
Into terminal count, just tested water deluge.
« Last Edit: 08/28/2021 10:16 pm by RocketLover0119 »
"The Starship has landed"

Offline RocketLover0119

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Re: Astra Rocket 3.3 – STP-27AD1 – Kodiak – August 28, 2021
« Reply #28 on: 08/28/2021 10:18 pm »
Clock has stopped at T-12 and a half minutes. Awaiting reason of hold.

Some config changes were made, count has resume at T-14 minutes.
« Last Edit: 08/28/2021 10:21 pm by RocketLover0119 »
"The Starship has landed"

Offline pb2000

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Re: Astra Rocket 3.3 – STP-27AD1 – Kodiak – August 28, 2021
« Reply #29 on: 08/28/2021 10:23 pm »
Count resumed.
Launches attended: Worldview-4 (Atlas V 401), Iridium NEXT Flight 1 (Falcon 9 FT), PAZ+Starlink (Falcon 9 FT), Arabsat-6A (Falcon Heavy)
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Offline RocketLover0119

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Re: Astra Rocket 3.3 – STP-27AD1 – Kodiak – August 28, 2021
« Reply #30 on: 08/28/2021 10:26 pm »
Final poll has occurred. Go for launch. Under 9 minutes to launch.
"The Starship has landed"

Offline pb2000

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Re: Astra Rocket 3.3 – STP-27AD1 – Kodiak – August 28, 2021
« Reply #31 on: 08/28/2021 10:33 pm »
T-2 minutes.
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Offline RocketLover0119

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Re: Astra Rocket 3.3 – STP-27AD1 – Kodiak – August 28, 2021
« Reply #32 on: 08/28/2021 10:34 pm »
T-1 Minute. Godspeed Astra!
"The Starship has landed"

Offline RocketLover0119

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Re: Astra Rocket 3.3 – STP-27AD1 – Kodiak – August 28, 2021
« Reply #33 on: 08/28/2021 10:35 pm »
LIFTOFF!!!

Power slide on liftoff!
« Last Edit: 08/28/2021 10:36 pm by RocketLover0119 »
"The Starship has landed"

Offline pb2000

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Re: Astra Rocket 3.3 – STP-27AD1 – Kodiak – August 28, 2021
« Reply #34 on: 08/28/2021 10:36 pm »
still flying tho
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Offline RocketLover0119

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Re: Astra Rocket 3.3 – STP-27AD1 – Kodiak – August 28, 2021
« Reply #35 on: 08/28/2021 10:37 pm »
T+2 minutes. Still flying!
"The Starship has landed"

Offline northenarc

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Re: Astra Rocket 3.3 – STP-27AD1 – Kodiak – August 28, 2021
« Reply #36 on: 08/28/2021 10:37 pm »
  Their flight computer doesn't quit! (whoops, there she goes, a noble effort)
« Last Edit: 08/28/2021 10:38 pm by northenarc »

Offline RocketLover0119

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Re: Astra Rocket 3.3 – STP-27AD1 – Kodiak – August 28, 2021
« Reply #37 on: 08/28/2021 10:38 pm »
ANOMALY!

vehicle has failed. Spun out of control at burnout.
« Last Edit: 08/28/2021 10:38 pm by RocketLover0119 »
"The Starship has landed"

Offline Jarnis

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Re: Astra Rocket 3.3 – STP-27AD1 – Kodiak – August 28, 2021
« Reply #38 on: 08/28/2021 10:38 pm »
Welp... Max Q and loss of control.

Offline pb2000

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Re: Astra Rocket 3.3 – STP-27AD1 – Kodiak – August 28, 2021
« Reply #39 on: 08/28/2021 10:38 pm »
its tumbling
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Re: Astra Rocket 3.3 – STP-27AD1 – Kodiak – August 28, 2021
« Reply #40 on: 08/28/2021 10:38 pm »
terminated
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Re: Astra Rocket 3.3 – STP-27AD1 – Kodiak – August 28, 2021
« Reply #41 on: 08/28/2021 10:38 pm »
"Terminate sent"
Which booster has the most soot? SpaceX booster launch history! (discussion)

I'll bet it tumbled because it was very low, and suffering under way more aerodynamic forces at burn-out than planned.
Wait, ∆V? This site will accept the ∆ symbol? How many times have I written out the word "delta" for no reason?

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Re: Astra Rocket 3.3 – STP-27AD1 – Kodiak – August 28, 2021
« Reply #43 on: 08/28/2021 10:41 pm »
Terminated!

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twitter.com/nasaspaceflight/status/1431747667177115649

Quote
LAUNCH! Astra's Rocket 3.3 vehicle, designated LV0006, launches from LP-3B at the Pacific Spaceport Complex in Kodiak, Alaska.

#PowerSlide!

Overview: nasaspaceflight.com/2021/08/astra-…

Play by Play:
forum.nasaspaceflight.com/index.php?topi…

NSF/Astra Livestream:
youtube.com/watch?v=O8Tdm7…

https://twitter.com/nasaspaceflight/status/1431748363427491853

Quote
Amazing it got uphill after that powerslide. Got to MECO and then it was terminated.

Offline cpushack

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There was a call out that the vehicle was 'approaching' a nominal trajectory, seems it never got there but WAS trying to get back on track.

Offline jstrotha0975

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How much more cash do they have to keep launching rockets that fail?

Offline chrisking0997

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nothing seemed normal about that, but on the other hand if it wasnt normal why didnt the FTS fire?  Maybe they just really enjoy dirtying up their launch site
Tried to tell you, we did.  Listen, you did not.  Now, screwed we all are.

Online kevinof

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Did they release the hold downs before full power was reached?
« Last Edit: 08/28/2021 10:43 pm by kevinof »

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The fact that it power slid and the TWR was exactly 1 at liftoff, one of the outer engines did not get up to nominal running.  I bet that was the scrub yesterday too and they just "modified" the program to ignore the slow startup.  I guess it was a slow startup for a reason.

Good luck next try Astra!!!!

Offline Mr. Scott

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Liftoff motion was really strange.  The rocket went -> -> -> -> -> -> -> -> -> -> -> -> that way then ^^^^^^^^^^^^ sort of then XXXXXXX*%^%$&$*&%*&%$*%%& KABOOM

wiggy
« Last Edit: 08/28/2021 11:19 pm by Mr. Scott »
Let’s Goooooooooo!

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https://twitter.com/astra/status/1431748557342601219

Quote
🚀 We suffered technical difficulties, but achieved 2.5 minutes of flight data. Every launch, whether successful or not, is an opportunity for us to learn. Our team will study the data and use this information to iterate on our next launch. #AdAstra

Offline RocketLover0119

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Screen grabs of launch. Definitely not nominal.
"The Starship has landed"

Offline DaveS

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The fact that it power slid and the TWR was exactly 1 at liftoff, one of the outer engines did not get up to nominal running.  I bet that was the scrub yesterday too and they just "modified" the program to ignore the slow startup.  I guess it was a slow startup for a reason.

Good luck next try Astra!!!!
Another item to investigate is that the two smaller hoses that was connected to the PLF didn't release on lift-off but several seconds afterwards.
"For Sardines, space is no problem!"
-1996 Astronaut class slogan

"We're rolling in the wrong direction but for the right reasons"
-USA engineer about the rollback of Discovery prior to the STS-114 Return To Flight mission

Offline chrisking0997

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that they had a failure video all ready to queue up doesnt exactly give confidence
Tried to tell you, we did.  Listen, you did not.  Now, screwed we all are.

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IIRC Astra use engine cutoff as their FSS. Engine shutdown occurred immediately before the tumble, and RSO called terminate sent, so the tumble is likely a result of FSS rather than the cause.

That powerslide on launch would have wasted a lot of prop on gravity losses, so unless they had exceptional margin the vehicle would have been outside its safety corridor at MECO anyway. Up until then, it was flying a nominal trajectory within its corridor (at reduced mass and a few seconds behind schedule) so no reason to terminate until then. More data more better.

Offline Bob Shaw

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The failure statement from the boss was gracious, and pre-recorded!

Offline Jrcraft

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The fact that it power slid and the TWR was exactly 1 at liftoff, one of the outer engines did not get up to nominal running.  I bet that was the scrub yesterday too and they just "modified" the program to ignore the slow startup.  I guess it was a slow startup for a reason.

Good luck next try Astra!!!!
Another item to investigate is that the two smaller hoses that was connected to the PLF didn't release on lift-off but several seconds afterwards.
I think we've seen those pop off when liftoff goes as planned, as they're pulled out by force of what should be a vertical liftoff.

Offline Bob Shaw

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that they had a failure video all ready to queue up doesnt exactly give confidence

It reflects realism and forward planning. A bit cynical, but certainly not dishonest.

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On lift off, something at the base of the vehicle is rapidly flipped up and impacts the side. Looks like the cable run aerocover.
« Last Edit: 08/28/2021 10:52 pm by edzieba »

Offline rocketmantitan

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The prelaunch chart showed MECO at T+2:50, I think.  So not sure why we had engine cutoff at T+2:30 ish.  But doesn't look like a planned MECO. I wonder if fairing deployment was tagged to 5 seconds after MECO (as opposed to a T+ time) - didn't see it go past the camera before the webcast cutaway.

Offline aviators99

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No commentary about the anomalous liftoff on the feed.  Don't understand.

Offline MaxTeranous

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When that tip and power slide started I was sure they were about to lose their GSE to a big kaboom. Pleased to see it make it to MECO in the end.

Better to try and fail than to not try at all.

No commentary about the anomalous liftoff on the feed.  Don't understand.

That's par for the course in launch failure commentary.
Wait, ∆V? This site will accept the ∆ symbol? How many times have I written out the word "delta" for no reason?

Offline RocketLover0119

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Initial thoughts: combing through launch it looks like something relating to either GSE or even an engine blowing happens, which cause the dramatic slide. The vehicle used up so much performance on ascent to counter act, and as a result MECO was significantly lower than it should’ve been, causing aerodynamics to be much greater, which in turn causes the vehicle to tumble.
"The Starship has landed"

Offline RocketLover0119

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The prelaunch chart showed MECO at T+2:50, I think.  So not sure why we had engine cutoff at T+2:30 ish.  But doesn't look like a planned MECO. I wonder if fairing deployment was tagged to 5 seconds after MECO (as opposed to a T+ time) - didn't see it go past the camera before the webcast cutaway.

MECO being lower was a result of the anomalous liftoff. Much more performance used, so therefore MECO happened significantly before it should’ve happened.
« Last Edit: 08/28/2021 10:57 pm by RocketLover0119 »
"The Starship has landed"

Offline russianhalo117

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Quote
🚀 We suffered technical difficulties, but achieved 2.5 minutes of flight data. Every launch, whether successful or not, is an opportunity for us to learn. Our team will study the data and use this information to iterate on our next launch. #AdAstra

Was the post-flight failure press conference also pre-recorded?

No he had different attire yesterday and the time of RSO flight termination would have had to have been dubbed in.

Offline Craftyatom

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nothing seemed normal about that, but on the other hand if it wasnt normal why didnt the FTS fire?  Maybe they just really enjoy dirtying up their launch site
Termination at MECO means that they burnt through most of their propellant during flight, and there's plenty of time for the remaining propellant to burn and debris to spread out on the way down.  Far more environmentally friendly than terminating over land - as Astra learned during one of their early attempts when they had to clean up large amounts of contaminated dirt.  Also saved their GSE.

So long as no humans or infrastructure are under increased risk (which is what the corridor is for), it's better to wait it out.  And if their GNC really did manage to keep it in the corridor with an engine out on liftoff, then huge props to their avionics team.

that they had a failure video all ready to queue up doesnt exactly give confidence
Famously, Nixon had a speech written by William Safire in case Neil Armstrong and Buzz Aldrin were stranded on the Moon.  More recently, we got confirmation that SpaceX (as expected) practiced statements to be made on stream in case of failures (something which NASA first learned to do after the Challenger disaster).

The prelaunch chart showed MECO at T+2:50, I think.  So not sure why we had engine cutoff at T+2:30 ish.  But doesn't look like a planned MECO. I wonder if fairing deployment was tagged to 5 seconds after MECO (as opposed to a T+ time) - didn't see it go past the camera before the webcast cutaway.

MECO being lower was a result of the anomalous liftoff. Much more performance used, so therefore MECO happened significantly before it should’ve happened.
  While MECO happened much lower and slower than it should've due to the increased gravity losses, if only 4 of the 5 engines were running then they should've burned for a longer period of time than usual - the opposite of what occurred.  This suggests that there are probably other factors involved, like the state of the non-functioning engine.
« Last Edit: 08/28/2021 11:07 pm by Craftyatom »
All aboard the HSF hype train!  Choo Choo!

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Tumbling after MECO was probably due to aerodynamic loads as it was to low in atmosphere. Booster spent almost 30s clearing pad, not most efficient launch but definitely coolest ever.

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Offline mrhuggy

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I have made a quick video of the launch frame by frame. It looked like it tipped over then managed to correct itself then took off. It also looks like they was either part of the hold down mechanism attached to it after launch or part of the rocket flipped up. There is also possible explosions, might be a engine failing. Actually it was hovering next to the pad for a while then when the fuel was burnt off it took off, again suggest a engine failed.

Source - NASASpaceflight and Astra Rocket Livestream.


« Last Edit: 08/28/2021 11:13 pm by mrhuggy »

Offline AirmanPika

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Not gonna lie...that was possibly the coolest "failure" ever. That powerslide...

Offline MarcPol

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Initial thoughts: combing through launch it looks like something relating to either GSE or even an engine blowing happens, which cause the dramatic slide. The vehicle used up so much performance on ascent to counter act, and as a result MECO was significantly lower than it should’ve been, causing aerodynamics to be much greater, which in turn causes the vehicle to tumble.

I'm inclined to think an engine blew just after the hold downs released, so it couldn't abort.  Scrubbing through the launch sequence frame by frame, there are a few frames during the power slide where the engine plumes can be seen between the clouds, and it does not look like 5 distinct plumes.  There's also a piece of raceway that slams up towards the camera, possibly from the shock of the engine in that slot blowing, and the rocket leans in that direction.  TVC compensates and keeps it vertical, while the thrust to weight ratio isn't high enough to accelerate upwards, and it hovers until enough propellant burns off for the TWR to be over 1 and it heads upwards. 

Offline Remes

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The channel for cables et al was blown away.

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https://twitter.com/nextspaceflight/status/1431751673312022528

Quote
Thank you to @Astra for letting the NASASpaceflight team cover the LV0006 test flight and for being willing to fail in front of a live audience. Not all companies have streamed launches before they have reached orbit for the first time.

Offline hartspace

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It reminded me a lot of an old Atlas missile that power slid off the pad.  It flew for a bit before it gave out.  I didn't think that the Astra was going to fly as long as it did after it started tipping and power sliding.  A pretty solid structure, if nothing else. Hopefully, they can fix the problem and fly again.

Offline tgr9898

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The channel for cables et al was blown away.

When the tumble starts you can see part of the rear skirt flapping as well.

Offline RocketLover0119

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GIF of launch zoomed in at the base of the rocket. Something relating to the GSE seems to have given way.
"The Starship has landed"

Offline brussell

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That's too bad. I hope for a quick recovery.

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I bet that the reason that it was slow and meco was early (unless it was from FTS) was cuz it was carrying a big heavy and draggy piece of GSE along for the ride so the engines never had to G-limit throttle down. Not to mention that it dramatically reduced the TWR and added a whole lot of drag possibly.

Offline Skyway

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What a tough design. This thing just insists to fly! Recover from that inclination demonstrate a very good flight computer and also excellent command authority, and of course, a well-projected structure to withstand that.

It gave a new meaning to the term " s*** going sideways".
Everything is fail-proof until it fails.

Offline panjabi

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Giant congrats to the dreamers, the believers, the doers, the workers who keep amazing the rest of us with their ingenuity and hard work.  Today did not end like the Astra team wanted to, but prayers and best wishes to the team for a fantastic success on your next launch.

You still did something today that is in the realm of dreams for most of us. The correction at launch was impressive and the fact that the rocket reached 40+ kms was completely unexpected (after the "electric slide" launch).

Look forward to future success with your amazing team! Keep those chins high and keep them rockets coming!
« Last Edit: 08/29/2021 03:32 am by panjabi »

Offline exilon

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Doubt it dragged much GSE along with it. Either a failed disconnect took out the nearest adjacent engine or the engine blew up and took out the other end of the GSE attachment. Motion is consistent with 1 failed engine; barely above 1 TWR and power sliding until it burned enough prop to start accelerating.

Offline Damon Hill

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I think that was the first lateral liftoff I've ever seen.  How did it even clear the launch hold-downs--was that why it tilted? Hopefully there's more footage from another angle.  SpaceX isn't the only company keeping the adventure alive in space technology development.
« Last Edit: 08/29/2021 12:09 am by Damon Hill »

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https://twitter.com/tgmetsfan98/status/1431770928627650564

Quote
In a post-launch media briefing, Astra CEO Chris Kemp says that 1 of the 5 Delphin engines on Stage 1 shut down less than 1 second into flight.

About 2.5 minutes into flight, the range commanded shutdown of all 5 engines.

https://twitter.com/nextspaceflight/status/1431770900534157315

Quote
Astra CEO Chris Kemp says that an engine shutdown less than 1 second into flight. Rocket managed to return to its trajectory for a bit until the range terminated the flight. The rocket returned to Earth without causing any damage to property.

Edit to add:

https://twitter.com/nextspaceflight/status/1431773524335599616

Quote
Spaceflight is crazy unforgiving. LV0006 seemed to recover amazingly well after it lost an engine. Who knows how far the rocket would have gone had that problematic engine worked properly. Will be interesting to see how quickly Astra can fix this issue and return to the pad.
« Last Edit: 08/29/2021 12:24 am by FutureSpaceTourist »

Offline kdhilliard

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Quote from: Thomas Burghardt
...
About 2.5 minutes into flight, the range commanded shutdown of all 5 engines.
Huh.  I wonder what the range violation was at that point.

Offline OneSpeed

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I'd take this with a grain of salt, but here is the available LV0006 telemetry, and a guess at the velocity before data resumed.

Offline meekGee

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The way the commentator says "Our next objective - Max Q!!!" as in  "What do you know...  I don't believe what I just saw but I'll take it!"

It lost 7 meters that I don't think it had on the pad.  Either it was following the hill down (Ground effect ?!?!?!?!) or the way the system figures altitude goes haywire when you're at ground level but a quarter mile away.

I agree with those that concluded it was able to climb since it burned fuel, and so this was an beautiful example of how a large number of engines creates redundancy.  A slightly higher number (hmm...  9?) and some propellant reserve (e.g for recovery) would have allowed T-0 engine loss and full mission recovery.

This system today was the opposite of brittle.
ABCD - Always Be Counting Down

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twitter.com/planet4589/status/1431770946717749250

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Launch of Astra LV0006 didn't go well, yet demonstrated impressive robustness of the design in extremis. Congrats to @Astra @Kemp on a good try and on an excellent, transparent livestream in collaboration with @NASASpaceflight. Hopefully next time will be the charm.

https://twitter.com/nextspaceflight/status/1431772300823588867

Quote
100%. Never thought a launch provider would be open enough to let us stream a launch for them, let alone let us pick which cameras go to air. We showed the flight all the way through termination. I think the YT comments speak for themselves. Transparency is the way to go.

Offline AirmanPika

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Remember that Homer gif into the bush? Well now we have...


Offline LouScheffer

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that they had a failure video all ready to queue up doesnt exactly give confidence
Famously, Nixon had a speech written by William Safire in case Neil Armstrong and Buzz Aldrin were stranded on the Moon.  More recently, we got confirmation that SpaceX (as expected) practiced statements to be made on stream in case of failures (something which NASA first learned to do after the Challenger disaster).
Eisenhower had a speech ready in case D-day failed.  The atomic bomb press crew had one statement in case of success (a remote ammo dump blew up) and three other statements in case of problems, ranging from "a few scientists were killed" up to "caused serious damage in the surounding communities".  Other similar speeches can be found here.

Smart people trying complicated things are all too well aware that failure IS an option.
« Last Edit: 08/29/2021 12:51 am by LouScheffer »

Offline thirtyone

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I have a feeling NSF is at least partly responsible for ensuring everyone was prepared for all potential failures in advance. They must be well aware of how to and how not to handle livestreamed rocket failures after seeing so many in the past with new LVs. As a previous poster mentioned, most experienced rocket companies do exactly the same.

Glad we all got to see that powerslide instead of a series of vague tweets about a rocket failure. Imagine if NSF weren't covering this! Great coverage for a developmental LV!

Also very happy to hear details about the failure so soon from the company. Admittedly it was probably a very obvious failure (loss of engine soon after liftoff, and no catastrophic failure until well after liftoff), but sometimes it takes forever for companies to even acknowledge that.
« Last Edit: 08/29/2021 01:04 am by thirtyone »

Offline kuldan

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I've been wondering that this has not been mentioned here - can anyone answer what might have happened at T-4 seconds? There's a loud "pop" that sounds kind of like a COPV that blew - not sure if Rocket 3.3 is even using COPVs anywhere near the engines, but could that be a possible failure mode - an overpressure event shortly before spinning up the engines, leading to one COPV blowing up and basically damaging an engine enough so it also blows on ignition? 

Offline AirmanPika

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So thing is...the rocket clearly performed. The fact that it made it to MECO means that it was working and likely the engines did not fail or underperform (maybe). Problem was it spent so much time compensating for whatever happened that it couldn't get to an optimal position to continue. I feel like something simply held on too long at release...or an engine didn't spin up as quickly as it should have but eventually hit full thrust.

Offline russianhalo117

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So thing is...the rocket clearly performed. The fact that it made it to MECO means that it was working and likely the engines did not fail or underperform (maybe). Problem was it spent so much time compensating for whatever happened that it couldn't get to an optimal position to continue. I feel like something simply held on too long at release...or an engine didn't spin up as quickly as it should have but eventually hit full thrust.
The CEO of Astra stated in his briefing an engine shutdown immediately at liftoff. The other liftoff anomalies were not mentioned. MECO is the stage one FTS system. With an engine shutdown the burn time would be longer not shorter. MECO was commanded followed by termination of the upper stage.The upper stage uses toxic propellant and was destroyed for protection.. Stop with the misinformation and speculation as it will not get you anywhere on this forum thanks to the report to moderator's function.
« Last Edit: 08/29/2021 01:49 am by russianhalo117 »

Offline cpushack

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So thing is...the rocket clearly performed. The fact that it made it to MECO means that it was working and likely the engines did not fail or underperform (maybe). Problem was it spent so much time compensating for whatever happened that it couldn't get to an optimal position to continue. I feel like something simply held on too long at release...or an engine didn't spin up as quickly as it should have but eventually hit full thrust.
The CEO of Astra stated in his briefing an engine shutdown immediately at liftoff. The other liftoff anomalies were not mentioned. MECO is the stage one FTS system. With an engine shutdown the burn time would be longer not shorter. MECO was commanded followed by termination of the upper stage.The upper stage uses toxic propellant and was destroyed for protection.. Stop with the misinformation and speculation as it will not get you anywhere on this forum thanks to the report to moderator's function.

Nothing toxic about the pressure fed Aether engine, it uses LOX/RP-1 just like the first stage.

Offline Pete

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Astra is really taking rocket launches in a new direction!






But seriously folks, I'm amazed the rocket managed to recover.
It is very good that the failure did not total their launch facility.
That the avionics managed to cope that well with an engine out *at launch* is quite impressive.
And I think they got some good data from the launch.
A.. successful failure, as such things go.

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Video of powerslide from LVs camera would be nice to see. Hope Astra release it in future.

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Offline RoadWithoutEnd

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Seems they got served a heaping helping of overt anomalies, rather than a sneaky head-scratcher like Rocket Lab was dealing with.  Hopefully that means solutions and RTF will be quicker in coming.
Walk the road without end, and all tomorrows unfold like music.

Offline russianhalo117

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Presser Permalink: https://investor.astra.com/news-releases/news-release-details/astra-conducts-test-launch

ALAMEDA, Calif.--(BUSINESS WIRE)--Aug. 28, 2021-- Astra Space, Inc. (“Astra”) (Nasdaq: ASTR) conducted a test launch of its launch vehicle, LV0006.

The launch vehicle lifted off at 3:35PM PT on Saturday, August 28, 2021. One of the five main engines shut down less than one second after liftoff, causing the vehicle to slowly lift off the pad before resuming its trajectory. After approximately two minutes and thirty seconds of flight, the range issued an all engine-shutdown command, ending the flight. The vehicle achieved an altitude of approximately 50 kilometers, before safely returning to Earth.

“We regret that we were unable to accomplish all mission objectives for the U.S. Space Force; however, we captured a tremendous amount of data from this test flight,” said Chris Kemp, Founder, Chairman and CEO of Astra. “We will incorporate learnings from this test into future launch vehicles, including LV0007, which is currently in production.”

Astra has opened a mishap investigation and is working closely with the Federal Aviation Administration (FAA).

About Astra Space

Astra’s mission is to improve life on Earth from space by creating a healthier and more connected planet. Astra’s first flight to space was within 4 years of its inception, making it the fastest company to reach space. Visit www.astra.com to learn more about Astra.

Safe Harbor Statement

Certain statements made in this press release are “forward-looking statements”. Forward-looking statements may be identified by the use of words such as “anticipate”, “believe”, “expect”, “estimate”, “plan”, “outlook”, and “project” and other similar expressions that predict or indicate future events or trends or that are not statements of historical matters. These forward-looking statements reflect the current analysis of existing information and are subject to various risks and uncertainties. As a result, caution must be exercised in relying on forward-looking statements. The following factors, among others, could cause actual results to differ materially from those described in these forward-looking statements: (i) our failure to meet projected development targets, including as a result of the decisions of governmental authorities or other third parties not within our control; (ii) changes in applicable laws or regulations; (iii) the ability of Astra to meet its financial and strategic goals, due to, among other things, competition; (iv) the ability of Astra to pursue a growth strategy and manage growth profitability; (v) the possibility that Astra may be adversely affected by other economic, business, and/or competitive factors; (vi) the effect of the COVID-19 pandemic on Astra and (vii) other risks and uncertainties discussed from time to time in our other public filings with the Securities and Exchange Commission.



View source version on businesswire.com: https://www.businesswire.com/news/home/20210828005021/en/

Media Contact:
Kati Dahm
[email protected]

Investor Contact:
Dane Lewis
[email protected]

Source: Astra Space, Inc.
« Last Edit: 08/29/2021 02:31 am by russianhalo117 »

Offline AirmanPika

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So thing is...the rocket clearly performed. The fact that it made it to MECO means that it was working and likely the engines did not fail or underperform (maybe). Problem was it spent so much time compensating for whatever happened that it couldn't get to an optimal position to continue. I feel like something simply held on too long at release...or an engine didn't spin up as quickly as it should have but eventually hit full thrust.
The CEO of Astra stated in his briefing an engine shutdown immediately at liftoff. The other liftoff anomalies were not mentioned. MECO is the stage one FTS system. With an engine shutdown the burn time would be longer not shorter. MECO was commanded followed by termination of the upper stage.The upper stage uses toxic propellant and was destroyed for protection.. Stop with the misinformation and speculation as it will not get you anywhere on this forum thanks to the report to moderator's function.


Offline AirmanPika

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Seems they got served a heaping helping of overt anomalies, rather than a sneaky head-scratcher like Rocket Lab was dealing with.  Hopefully that means solutions and RTF will be quicker in coming.

I think their circumstances were lucky also. In many cases a failure like this would result in an immediate abort/termination. Thanks to location they could continue to fire and gather data which is insanely valuable. As mentioned in the press release (that I am aware of now) an engine failed but it kept trying hard and kept chugging along. That's quite a testament to the guidance system.

Offline illectro

Chris Kemp posted another camera angle, showing the flip side of this, but nothing new I can make out:

https://twitter.com/kemp/status/1431812555324854272?s=21

Offline Steven Pietrobon

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There was something poking out during the burn. After MECO, it rotates into view, but then appears to have been ripped off while the vehicle spun up.
« Last Edit: 08/29/2021 04:31 am by Steven Pietrobon »
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline cscott

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Pretty sure that's the cable cover you can see being dislodged at takeoff.


GIF of launch zoomed in at the base of the rocket. Something relating to the GSE seems to have given way.


The channel for cables et al was blown away.

« Last Edit: 08/29/2021 04:35 am by cscott »

Offline sghill

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Holy moly!!

The only thing missing from this insane launch video is a bunch of technicians in lab coats running down the road after the rocket while the Benny Hill theme plays!

Chris Kemp posted another camera angle, showing the flip side of this, but nothing new I can make out:

https://twitter.com/kemp/status/1431812555324854272?s=21
Bring the thunder!

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Holy moly!!

The only thing missing from this insane launch video is a bunch of technicians in lab coats running down the road after the rocket while the Benny Hill theme plays!

Chris Kemp posted another camera angle, showing the flip side of this, but nothing new I can make out:

https://twitter.com/kemp/status/1431812555324854272?s=21

Someone was smart enough to open the perimeter gate so the rocket could escape out.;-)
Tony De La Rosa

Offline AirmanPika

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Holy moly!!

The only thing missing from this insane launch video is a bunch of technicians in lab coats running down the road after the rocket while the Benny Hill theme plays!

Chris Kemp posted another camera angle, showing the flip side of this, but nothing new I can make out:

https://twitter.com/kemp/status/1431812555324854272?s=21

heh

Offline PM3

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MECO being lower was a result of the anomalous liftoff. Much more performance used, so therefore MECO happened significantly before it should’ve happened.
  While MECO happened much lower and slower than it should've due to the increased gravity losses, if only 4 of the 5 engines were running then they should've burned for a longer period of time than usual - the opposite of what occurred.  This suggests that there are probably other factors involved, like the state of the non-functioning engine.

Except if the four engines run at much higher throttle (and thus less efficient combustion?) than planned throughout flight, trying to compensate for the engine-out and gravity losses. Flying too low also can mean less engine effiency due to higher atmospheric pressure.
« Last Edit: 08/29/2021 07:17 am by PM3 »
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Offline Steven Pietrobon

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Except if the four engines run at much higher throttle (and thus less efficient combustion?)...

Generally, rocket engines are more efficient as you increase the chamber pressure and thus the thrust.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline tyrred

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Chris Kemp posted another camera angle, showing the flip side of this, but nothing new I can make out:

https://twitter.com/kemp/status/1431812555324854272?s=21

The more I watched it from this angle, the more it appeared the flamey end bumped and rebounded slightly off of the strongback, reversing the topple over and instead helping to reorient the pointy end back up.

Strongback assisted powerslide?

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twitter.com/robotbeat/status/1431755207835373574

Quote
It was awesome. I’ve never seen that before. I thought it was an immediate explosion, but it proved it wanted to reach for the stars anyway. Ad astera per aspera.

https://twitter.com/rocketrepreneur/status/1431830674034642945

Quote
Their original GN&C lead was Masten's GN&C lead during the NGLLC. He left a while ago, but I'm not surprised he and the others made something that kept fighting that hard.

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They're very lucky that the engine that failed caused it to pitch downrange, and not straight into the strongback! They're also lucky it had that little vertical kick of ~1m before the engine fully stopped, otherwise they might have got snagged on part of the launch structure.

I wonder if the umbilical check valve / purge system didn't work, causing an overpressure / explosion (I think the 2nd F9 launch had that happen? But to the ground side side hose luckily)

Offline Stan-1967

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There could be some very relevant data on the effect of ground plume impingement on unprepared surfaces.  I think I can see in the video the moment it slides/flies off the concrete over bare earth.  The plume gets dirtier.   Lucky it didn’t hit a tree.

Offline Vonbraun

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The effect on the ground surface is surprisingly benign.

I wonder if you could perhaps tilt eg. Starship launch structure 1 degree towards the coast and have simple sand pit laid over there. This way it would provide "guaranteed" infrastructure clearance or abort to higher altitude when things go haywire, on normal launch the ship would just re-orient in an instant.
« Last Edit: 08/29/2021 03:30 pm by Vonbraun »

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I have had so many kerbal launches that look exactly like this one

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The effect on the ground surface is surprisingly benign.
The exhaust plume did benign its way through the upper layer of concrete as it passed over the pad.

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<snark>
definitely not controlled by Boeing software!
</snark>

Seriously - major props to Astra for their flight control software - never gave up , never surrendered.

They will get to orbit next launch or two - if they don't run out of money.
"Better a diamond with a flaw than a pebble without." - Confucius

Offline kdhilliard

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...
Someone was smart enough to open the perimeter gate so the rocket could escape out.;-)
Ha!
Attached is a screenshot from 3:41 in Scott Manley's video showing a before-and-after view of the launch pad, with an engine-plowed trench straight out through the middle of the gate!


Also, Manley's take on the timing of the flight termination, from 9:53 in his video:
Quote from: Scott Manley
I think the reason they called the flight termination before MECO was that they wanted to make sure that the booster fell into this first exclusion zone.  They wanted to keep it flying long enough that it wouldn't land on the island. I think they were happy to get some flight time on it to verify other systems.  But if they let it run too long, it would have probably ended up between those two zones and that would have caused a bit of consternation with the FAA.
Attached exclusion zone image from 10:00 of the video.
Credited by Manley to this post upthread by Ken the Bin.

But...
That Up-Range hazard area runs out to about 180 km from the pad.
The Down-Range hazard area runs from about 1330 km to 2200 km from the pad.

Just how far down range did Astra expect the first stage to fall had this flight gone to plan?
Naively, I would have expected a distance somewhere between those hazard areas.
« Last Edit: 08/29/2021 08:19 pm by kdhilliard »

Offline Greg906

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Thanks for creating a side by side of the pad before and after!

What kind of risk was there of FOD impact on the booster as it blew apart the concrete?  Any guesses?


Offline Vonbraun

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The effect on the ground surface is surprisingly benign.
The exhaust plume did benign its way through the upper layer of concrete as it passed over the pad.

I think that is just dirt over the concrete.

Offline joek

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What Astra just showed is why you need to thoroughly check that all your engines are running correctly before liftoff. If you do that correctly, then the failure Astra had isn't possible, no matter how many engines you have.

Astra stated the engine failed less than a second after liftoff--which I take as after all engines were verified to be performing nominally prior to clamp release (liftoff). Engine failure could happen to any LV, whether 1ms, 1 second, or 1 minute after release. Maybe Astra needs to improve verification of nominal engine performance prior to release; maybe it was GSE-related. We don't know enough to say at this point.

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What Astra just showed is why you need to thoroughly check that all your engines are running correctly before liftoff. If you do that correctly, then the failure Astra had isn't possible, no matter how many engines you have.

Astra stated the engine failed less than a second after liftoff--which I take as after all engines were verified to be performing nominally prior to clamp release (liftoff). Engine failure could happen to any LV, whether 1ms, 1 second, or 1 minute after release. Maybe Astra needs to improve verification of nominal engine performance prior to release; maybe it was GSE-related. We don't know enough to say at this point.

They scrubbed the day before because of a slow startup of one or more engines.

Explanation for yesterday’s abort: engines appeared to start-up a little slower than expected, so vehicle aborted. Today they’ve preconditioned the vehicle (in an earlier hold) which should resolve the issue for today’s attempt.

Edit to add:

https://twitter.com/nasaspaceflight/status/1431724835571474443

Quote
Astra has made some operational adjustments to counter yesterday's abort (slow engine ramp up), including a reconditioning hold earlier in today's count (thus the more to the right for the T-0).

T-55 mins.

➡️youtube.com/watch?v=O8Tdm7…

So they did check and something was off.  They "adjusted" things and tried again.  The engine tried to warn them the first time in my opinion.

Can anyone verify if the slow startup engines was the one that died?

Offline chrisking0997

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so the consensus seems to be that this was an acceptable anomoly profile, lateral movement until vertical velocity occurred vs FTS activation.  So were they just lucky that the engine that failed caused to vehicle to pitch in probably the most optimal direction to allow that path (which you have to wonder if they put the gate there for that very possibility?) or do we think the vehicle commanded that movement?  Would be interesting to know, and if its the later then that is pretty darn impressive
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Offline darkenfast

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so the consensus seems to be that this was an acceptable anomoly profile, lateral movement until vertical velocity occurred vs FTS activation.  So were they just lucky that the engine that failed caused to vehicle to pitch in probably the most optimal direction to allow that path (which you have to wonder if they put the gate there for that very possibility?) or do we think the vehicle commanded that movement?  Would be interesting to know, and if its the later then that is pretty darn impressive

There seem to be three sections of fencing removed just before launch because of the way the pad diverts the jet.
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Offline launchwatcher

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so the consensus seems to be that this was an acceptable anomoly profile, lateral movement until vertical velocity occurred vs FTS activation.
Earlier posts on this thread suggest that Astra does not have a pyrotechnic FTS; the "FTS" just cuts the engines.
No doubt there's enough wide open unpopulated space around their launch area in on Kodiak Island that this is sufficient to keep regulators and insurers happy.

Offline SpeakertoAnimals

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There could be some very relevant data on the effect of ground plume impingement on unprepared surfaces.  I think I can see in the video the moment it slides/flies off the concrete over bare earth.  The plume gets dirtier.   Lucky it didn’t hit a tree.
Cool, we are entering a new age. If I may paraphrase, "We are lucky our orbital rocket didn't hit a tree."

Offline AstroDave

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  Looking at Astra wiki page, it showed a tentative schedule of two more flights (#7 & #8) before year end. Launch schedules are always optimistic, but with the anomaly on this past flight does Astra attempt another launch again before year end? Or, is their next attempt pushed into 2022? Is there any good information about status of hardware for future orbital attempt?
  Aware there are lots of unknowns here, but was interested in some informed opinions.

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Someone was smart enough to open the perimeter gate so the rocket could escape out.;-)

That's the understatement of the month. Probably without that , it would have tumbled immediately after hiting the fence.

Does anyone know the T/W of Astra ? I mean it perfectly hovered sideways which is really strange, what's the likelyhood of that ?
« Last Edit: 08/30/2021 10:39 am by savantu »

Offline Yggdrasill

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That's the understatement of the month. Probably without that , it would have tumbled immediately after hiting the fence.
Probably not, imho. I think the fence would lose that encounter.

The rocket could have hit the masts for cameras/lights/etc, though, not to mention the launch tower, so it was quite lucky that it didn't explode right next to the pad.

Does anyone know the T/W of Astra ? I mean it perfectly hovered sideways which is really strange, what's the likelyhood of that ?
Scott Manley mentioned a T/W of 1.25, which makes perfect sense. Losing one out of five engines would then drop the T/W to exactly 1. And then it would climb from there as it burns though propellant and gets lighter.

I think for this specific design, it's maybe not that unlikely. Typical T/W is often around 1.2-ish, so this scenario where you lose an engine and end up with a T/W of approximately 1 is really only likely to occur on a vehicle with 5-6 engines. That excludes every(?) other launch vehicle.
« Last Edit: 08/30/2021 11:00 am by Yggdrasill »

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Does anyone know the T/W of Astra ? I mean it perfectly hovered sideways which is really strange, what's the likelyhood of that ?
Scott Manley mentioned a T/W of 1.25, which makes perfect sense. Losing one out of five engines would then drop the T/W to exactly 1. And then it would climb from there as it burns though propellant and gets lighter.

I think for this specific design, it's maybe not that unlikely. Typical T/W is often around 1.2-ish, so this scenario where you lose an engine and end up with a T/W of approximately 1 is really only likely to occur on a vehicle with 5-6 engines. That excludes every(?) other launch vehicle.

1.2 is very much at the low end. Saturn V was around 1.2, and they were really pushing the mass as far as they could while bumping against the limits of 1960s engine technology. The Falcons are over 1.4, even Electron is well over 1.3, not to speak of solids. Atlas exceeds 1.6 with only two solids. The Russians like to go over 1.5, as high thrust and good density play into the strengths of kerolox.

At 1.2, gravity losses become more noticeable and more importantly for an early attempt, they will need to uprate their engines or put in more for any stretch or payload increase.
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Offline Ken the Bin

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Chris Kemp provided this information about the TWR:

https://twitter.com/Kemp/status/1431831601445425157

Quote from: Chris Kemp
Five engines is 1.25:1 by design, in case this exact scenario happened.  With one out ~1:1 - for a few seconds - until some fuel is burned.

Offline meekGee

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Someone was smart enough to open the perimeter gate so the rocket could escape out.;-)

That's the understatement of the month. Probably without that , it would have tumbled immediately after hiting the fence.

Does anyone know the T/W of Astra ? I mean it perfectly hovered sideways which is really strange, what's the likelyhood of that ?
It was too precisely balanced..  If the T/W ratio was 1.24 or 1.26, it would have crashed in seconds or taken off..

Not to mention that propellant was being expended, and 10 seconds of almost full thrust is a lot of weight.

I think it was a sort of ground effect, even though the traditional type is not possible with a supersonic exhaust.  Call it blow back.  Just enough to balance the books.
« Last Edit: 08/30/2021 12:11 pm by meekGee »
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Offline Yggdrasill

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1.2 is very much at the low end. Saturn V was around 1.2, and they were really pushing the mass as far as they could while bumping against the limits of 1960s engine technology. The Falcons are over 1.4, even Electron is well over 1.3, not to speak of solids. Atlas exceeds 1.6 with only two solids. The Russians like to go over 1.5, as high thrust and good density play into the strengths of kerolox.

At 1.2, gravity losses become more noticeable and more importantly for an early attempt, they will need to uprate their engines or put in more for any stretch or payload increase.
Fair enough. My point was really that there is a limited number of launch vehicles with 3-6 engines, which is where the scenario is most likely to occur. The number of engines must match the T/W of the launch vehicle, to drop down to a T/W of exactly 1 in the event one engine dies.

1. A LV with three engines needs a T/W of 1.5 to drop down to a T/W of 1 in the event one engine fails.
2. A LV with four engines needs a T/W of 1.33 to drop down to a T/W of 1 in the event one engine fails.
3. A LV with five engines needs a T/W of 1.25 to drop down to a T/W of 1 in the event one engine fails.
4. A LV with six engines needs a T/W of 1.2 to drop down to a T/W of 1 in the event one engine fails.

I can really only think of Astra that is close to one of the above scenarios. (And there are also some considerations like gimbal range that also matter. It's more likely to work with 5-6 engines than with 3-4 engines.)
« Last Edit: 08/30/2021 01:48 pm by Yggdrasill »

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Will be interesting to see what caused the engine failure if it was the engine or something related to the running design changes from the previous unit that nearly reached the target. Hope Astra is ready to try again very soon. Tremendous faith in the team!

Offline Craftyatom

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So they did check and something was off.  They "adjusted" things and tried again.  The engine tried to warn them the first time in my opinion.

Can anyone verify if the slow startup engines was the one that died?
So far, this is what has been said on the matter, AFAIK (link):
Quote from: SpaceNews
A launch attempt the previous day was aborted an instant after engine ignition, which Astra later said was because the engine thrust wasn’t ramping up as fast as expected. “Right now we have no reason to believe these are related,” Kemp said.
All aboard the HSF hype train!  Choo Choo!

Offline Lars-J

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Someone was smart enough to open the perimeter gate so the rocket could escape out.;-)

That's the understatement of the month. Probably without that , it would have tumbled immediately after hiting the fence.

Does anyone know the T/W of Astra ? I mean it perfectly hovered sideways which is really strange, what's the likelyhood of that ?
It was too precisely balanced..  If the T/W ratio was 1.24 or 1.26, it would have crashed in seconds or taken off..

Not to mention that propellant was being expended, and 10 seconds of almost full thrust is a lot of weight.

I think it was a sort of ground effect, even though the traditional type is not possible with a supersonic exhaust.  Call it blow back.  Just enough to balance the books.

Huh? That makes no sense. What alternate form of physics are you using to assert that 1.26 would have been catastrophic where 1.25 was not?  :o
« Last Edit: 08/30/2021 05:43 pm by Lars-J »

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Huh? That makes no sense. What alternate form of physics are you using to assert that 1.26 would have been catastrophic where 1.25 was not?  :o

I think the claim is basically "if with 4/5 engines functioning, it had 1.01 TWR instead of 1.00, it would've ascended ("taken off") rather than hovered; that wouldn't have ultimately changed the rocket's fate, but it wouldn't match what we saw happen." However, I doubt that it was that sensitive to the exact TWR.

Offline Lee Jay

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Huh? That makes no sense. What alternate form of physics are you using to assert that 1.26 would have been catastrophic where 1.25 was not?  :o

I think the claim is basically "if with 4/5 engines functioning, it had 1.01 TWR instead of 1.00, it would've ascended ("taken off") rather than hovered; that wouldn't have ultimately changed the rocket's fate, but it wouldn't match what we saw happen." However, I doubt that it was that sensitive to the exact TWR.

Yeah - it would have "taken off" at an acceleration of 0.01g = 0.098m/s^2 which means after 10 seconds it would have been ascending at a whopping 0.98m/s.  Since the smoke/dust/whatever obscured the camera view, we can't tell if it was in a perfect hover or not.  It may have descended slightly, hovered for a moment and started ascending slightly as fuel burned off, all before we saw it emerge from the smoke/dust/whatever and start picking up acceleration.

Online TrevorMonty

Huh? That makes no sense. What alternate form of physics are you using to assert that 1.26 would have been catastrophic where 1.25 was not?  :o

I think the claim is basically "if with 4/5 engines functioning, it had 1.01 TWR instead of 1.00, it would've ascended ("taken off") rather than hovered; that wouldn't have ultimately changed the rocket's fate, but it wouldn't match what we saw happen." However, I doubt that it was that sensitive to the exact TWR.

Yeah - it would have "taken off" at an acceleration of 0.01g = 0.098m/s^2 which means after 10 seconds it would have been ascending at a whopping 0.98m/s.  Since the smoke/dust/whatever obscured the camera view, we can't tell if it was in a perfect hover or not.  It may have descended slightly, hovered for a moment and started ascending slightly as fuel burned off, all before we saw it emerge from the smoke/dust/whatever and start picking up acceleration.
May have been camera angle but after smoke cleared LV seem quite a distance away an well downhill before it started slow ascent.

I think it followed land down hill to some cliffs over the sea before gaining height. Shows negative speed ie falling in bottom right of video.


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Offline Yggdrasill

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It showed negative speed while clearly ascending. So the telemetry from the feed can't be trusted.

My impression from the video is that is started climbing right from the start, although very slowly, and didn't decend (until after termination).



(Jump to 30 seconds in.)
« Last Edit: 08/30/2021 06:55 pm by Yggdrasill »

Offline Lars-J

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Huh? That makes no sense. What alternate form of physics are you using to assert that 1.26 would have been catastrophic where 1.25 was not?  :o

I think the claim is basically "if with 4/5 engines functioning, it had 1.01 TWR instead of 1.00, it would've ascended ("taken off") rather than hovered; that wouldn't have ultimately changed the rocket's fate, but it wouldn't match what we saw happen." However, I doubt that it was that sensitive to the exact TWR.

Yes but keep in mind that the 5th engine provided thrust for a significant fraction of a second which would have resulted in a slight upwards motion which would turn into a linear motion once the engine died. (keeping the slight upwards momentum) I don't see any evidence that a ground effect was necessary to explain what we saw.
« Last Edit: 08/30/2021 09:51 pm by Lars-J »

Offline meekGee

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Someone was smart enough to open the perimeter gate so the rocket could escape out.;-)

That's the understatement of the month. Probably without that , it would have tumbled immediately after hiting the fence.

Does anyone know the T/W of Astra ? I mean it perfectly hovered sideways which is really strange, what's the likelyhood of that ?
It was too precisely balanced..  If the T/W ratio was 1.24 or 1.26, it would have crashed in seconds or taken off..

Not to mention that propellant was being expended, and 10 seconds of almost full thrust is a lot of weight.

I think it was a sort of ground effect, even though the traditional type is not possible with a supersonic exhaust.  Call it blow back.  Just enough to balance the books.

Huh? That makes no sense. What alternate form of physics are you using to assert that 1.26 would have been catastrophic where 1.25 was not?  :o
The type that reads what I wrote....

I said that the precise balancing was odd.  If it was 1.26, the rocket would have ascended.  If it was 1.24, it would have crashed.  What are the odds?

I also noted that as the rocket got lighter, it didn't immediately start to ascend.

So instead of miracles, I was suggesting a simple feed-back loop that would balance it at a constant distance from the ground until it got light enough to ascend.
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Offline meekGee

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Huh? That makes no sense. What alternate form of physics are you using to assert that 1.26 would have been catastrophic where 1.25 was not?  :o

I think the claim is basically "if with 4/5 engines functioning, it had 1.01 TWR instead of 1.00, it would've ascended ("taken off") rather than hovered; that wouldn't have ultimately changed the rocket's fate, but it wouldn't match what we saw happen." However, I doubt that it was that sensitive to the exact TWR.

Yes but keep in mind that the 5th engine provided thrust for a significant fraction of a second which would have resulted in a slight upwards motion which would turn into a linear motion once the engine died. (keeping the slight upwards momentum) I don't see any evidence that a ground effect was necessary to explain what we saw.

Actually that fits the profile.

It had positive T/W for a second.  But not quite 1.25.  Something lower.

Then when the engine was lost, it stopped ascending and settled back down.    Until it got close enough for the blow-back to balance it.

There it maintained the status quo even as it burned propellant, until it eventually got light enough for T/W to get back over 1.0 and off it went.

According to my strange version of physics, if it had an upwards velocity and then T/W was "exactly" 1.0, then it would have continued to rise, since air resistance at that velocity is zero.  It would not have suddenly stopped.
« Last Edit: 08/31/2021 02:27 am by meekGee »
ABCD - Always Be Counting Down

Offline Comga

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Huh? That makes no sense. What alternate form of physics are you using to assert that 1.26 would have been catastrophic where 1.25 was not?  :o

I think the claim is basically "if with 4/5 engines functioning, it had 1.01 TWR instead of 1.00, it would've ascended ("taken off") rather than hovered; that wouldn't have ultimately changed the rocket's fate, but it wouldn't match what we saw happen." However, I doubt that it was that sensitive to the exact TWR.

Yes but keep in mind that the 5th engine provided thrust for a significant fraction of a second which would have resulted in a slight upwards motion which would turn into a linear motion once the engine died. (keeping the slight upwards momentum) I don't see any evidence that a ground effect was necessary to explain what we saw.

Actually that fits the profile.

It had positive T/W for a second.  But not quite 1.25.  Something lower.

Then when the engine was lost, it stopped ascending and settled back down.    Until it got close enough for the blow-back to balance it.

There it maintained the status quo even as it burned propellant, until it eventually got light enough for T/W to get back over 1.0 and off it went.

According to my strange version of physics, if it had an upwards velocity and then T/W was "exactly" 1.0, then it would have continued to rise, since air resistance at that velocity is zero.  It would not have suddenly stopped.

"Engineering is done with numbers"
Lots of numbers
Fortunately we have good sources of numbers.
Someone (Onespeed?) could go frame by frame, using the 1.32 m diameter of the rocket for scale and derive the rocket's altitude vs time.
We could then play with the three basic variables:
Time from clamp release to engine failure
Thrust to Weight ratio PER ENGINE
Some form of mass decrease with time or acceleration increase with time.
Then calculate a series of accelerations, velocities, and altitudes.
Shy of a good, grownup way to crunch the numbers, they can be put in an all-purpose spreadsheet.
Here is a graph of one such scenario
It uses 0.23 TWR/engine, which goes from 1.15 at T<Tout=0.61 to 0.92 afterwards
It includes 0.02 g/sec "jerk" (rate of change of acceleration) per engine as the fuel burns off.
The nosecone goes up a bit under 2 meters by T=3, falls off to just over 1 m around T=7 and then takes off.
After 2 min 30 sec (150 sec) the vehicle is just below 80 km, but that's in the absence of drag.
That's not a terrible match.
It could be improved, but it doesn't need new physics like ground effect with supersonic flow.

So the TWR is significantly less than 1.25 at clamp release, and the engine goes out at well less than one second.
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline high road

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Someone was smart enough to open the perimeter gate so the rocket could escape out.;-)

That's the understatement of the month. Probably without that , it would have tumbled immediately after hiting the fence.

Does anyone know the T/W of Astra ? I mean it perfectly hovered sideways which is really strange, what's the likelyhood of that ?
It was too precisely balanced..  If the T/W ratio was 1.24 or 1.26, it would have crashed in seconds or taken off..

Not to mention that propellant was being expended, and 10 seconds of almost full thrust is a lot of weight.

I think it was a sort of ground effect, even though the traditional type is not possible with a supersonic exhaust.  Call it blow back.  Just enough to balance the books.

Huh? That makes no sense. What alternate form of physics are you using to assert that 1.26 would have been catastrophic where 1.25 was not?  :o
The type that reads what I wrote....

I said that the precise balancing was odd.  If it was 1.26, the rocket would have ascended.  If it was 1.24, it would have crashed.  What are the odds?

I also noted that as the rocket got lighter, it didn't immediately start to ascend.

So instead of miracles, I was suggesting a simple feed-back loop that would balance it at a constant distance from the ground until it got light enough to ascend.

The rocket could have been actively balancing it, using whatever reserves it had to gimbal the engines and reduce the lateral movement, reducing vertical thrust. The rocket was no longer moving sideways by the time it came above the trees.
« Last Edit: 08/31/2021 05:45 am by high road »

Offline OneSpeed

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Lots of numbers

Here's a plot of the first 8 seconds of flight. Normally, we just analyse the magnitude of the position vector, but in this case, it's worth looking at the X and Y components separately.

So, in the first second, the horizontal acceleration 'X (m/s²)' is minimal, as you would expect for a nominal launch. Meanwhile, the vertical acceleration 'Y (m/s²)' is building steadily.

But, at T+0:01 an engine fails, and from the rotation evident in the video, it is not a centre one. The remaining engines have not yet gimballed at this point, so the rocket quickly rotates, and vertical acceleration goes briefly negative, as horizontal acceleration rapidly increases.

By T+0:02, the flight computer has begun to compensate for excessive rotation with gimbal, and by T+0:05 it is vertical again, but still travelling horizontally at a constant 1.5m/s.

At the same time, vertical acceleration goes slightly positive, and the rocket begins it's gradual recovery from a marginal situation. It's perhaps worth noting that at no point does the rocket's vertical velocity ever go negative.

Edit: not a centre engine
« Last Edit: 08/31/2021 01:36 pm by OneSpeed »

Offline brussell

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But, at T+0:01 an engine fails, and from the rotation evident in the video, it is not the centre one. The remaining engines have not yet gimballed at this point, so the rocket quickly rotates, and vertical acceleration goes briefly negative, as horizontal acceleration rapidly increases.

Nice! (Just a quick comment, there's no center engine)

Offline Skyrocket

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Lots of numbers
But, at T+0:01 an engine fails, and from the rotation evident in the video, it is not the centre one. The remaining engines have not yet gimballed at this point, so the rocket quickly rotates, and vertical acceleration goes briefly negative, as horizontal acceleration rapidly increases.

Just a note: The Astra Rocket 3 does not have a center engine.

Offline MaxTeranous

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To add, the thrust in the Y axis (and therefore the numerator of the T/W ratio) for each engine is not a constant, it will vary with gimballing, and we know the engines will have had to do that to recover the X axis powerslide. So the depleting weight of the rocket isn’t the only component of the changing T/W over time, at least in the “going up” axis!
« Last Edit: 08/31/2021 01:47 pm by MaxTeranous »

Offline Lee Jay

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To add, the thrust in the Y axis (and therefore the numerator of the T/W ratio) for each engine is not a constant, it will vary with gimballing, and we know the engines will have had to do that to recover the X axis powerslide. So the depleting weight of the rocket isn’t the only component of the changing T/W over time, at least in the “going up” axis!

Yeah, but that's a cosine change, which is very small at small angles (cos(small angle) ~= 1).

Offline MaxTeranous

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To add, the thrust in the Y axis (and therefore the numerator of the T/W ratio) for each engine is not a constant, it will vary with gimballing, and we know the engines will have had to do that to recover the X axis powerslide. So the depleting weight of the rocket isn’t the only component of the changing T/W over time, at least in the “going up” axis!

Yeah, but that's a cosine change, which is very small at small angles (cos(small angle) ~= 1).

Certainly, 8 degrees is about 1%. But we’re talking about a situation very near a T/W of 1.0, 1% in this could make a larger impact than nominal use.

Offline illectro

For those doing math, you don’t need to spend much time thinking about total mass and thrust, it’s all about specific impulse which is probably around 310 (Rocketlab’s electron is 311)

Specific impulse tells us how long 1 unit mass of propellent can lift itself from gravity.

Therefore the rocket mass is being reduced by the inverse of the specific impulse every second. I.e. 1/310 => 0.32% every second.

Also, if you’re analyzing the images remember that the camera is at an angle and the rocket is moving away from this, so while it looks mostly level it’s actually going up.

Offline mother

If I look at photos of the engine bell collar, which are pear-shaped, it would seem like the only significant motion the engines are allowed is along the circumference of the vehicle, only affecting roll.

Are we totally sure they don't use differential thrust? I also don't see the plumes move as they obviously do on F9 first stage recoveries, when adjustments of similar pitch changes are made. The F9 is not vertical until very close to the barge, when a thrust vector change is clearly observed, cancelling the lateral motion, placing the vehicle vertical, and finally landing.

IMHO the Astra rocket was using differential, and as such it needs to have a thrust overhead for positive authority over pitch and yaw. I have attached the normal configuration of forces around one of the control axis, and what happens when we lose an engine.

It seems evident that the two engines closes to the axis have a hard time to overcome the thrust exerted by the other two engines further away. In order not to topple, the guidance system would need to leave the thrust of engines 3 & 4 at their present level, and increase thrust on 2 & 5 to the maximum afforded by the differential control overhead. Slowly but surely, lateral motion is cancelled out, leading to the ability to increase thrust on 2 & 5 again, increasing rate of ascent.

I could be totally off-piste here, I'll let the experts tell me I'm a idiot :-)

Offline Steven Pietrobon

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If I look at photos of the engine bell collar, which are pear-shaped, it would seem like the only significant motion the engines are allowed is along the circumference of the vehicle, only affecting roll.

The pear shape could be due to leaving room for the turbo pump. The Saturn IB also had a pear shaped collar for the four outer engines, each of which could move in two directions.

https://www.alamy.com/stock-photo-saturn-ib-rocket-the-rocket-garden-kennedy-space-center-visitor-complex-41489040.html

Go to 17:43 in the video below to see an outer engine move.

« Last Edit: 09/01/2021 07:41 am by Steven Pietrobon »
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Online edzieba

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Falcon 9 is another example with 2-axis engine gimbal and pear-shaped flex sections (the Merlin turbopump exhausts have their own separate openings).

Offline Lars-J

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If I look at photos of the engine bell collar, which are pear-shaped, it would seem like the only significant motion the engines are allowed is along the circumference of the vehicle, only affecting roll.
Incorrect. (As others have noted)
Besides if your assumption was right, the engines could only gimbal in one direction to roll the rocket, but not roll it the other way.

No they can certainly gimbal in all directions.

No they can certainly gimbal in all directions.

Not that they need to of course. 1-axis of gimbal on a ring of only 3 engines would be enough to give you full control. It's just as possible with a ring of 5, although I imagine the TVC programming would be pretty annoying.
Wait, ∆V? This site will accept the ∆ symbol? How many times have I written out the word "delta" for no reason?

Offline MaxTeranous

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No they can certainly gimbal in all directions.

Not that they need to of course. 1-axis of gimbal on a ring of only 3 engines would be enough to give you full control. It's just as possible with a ring of 5, although I imagine the TVC programming would be pretty annoying.

And not resilient to an engine out worth a damn!

Offline brussell

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If I look at photos of the engine bell collar, which are pear-shaped, it would seem like the only significant motion the engines are allowed is along the circumference of the vehicle, only affecting roll.

Are we totally sure they don't use differential thrust? I also don't see the plumes move as they obviously do on F9 first stage recoveries, when adjustments of similar pitch changes are made. The F9 is not vertical until very close to the barge, when a thrust vector change is clearly observed, cancelling the lateral motion, placing the vehicle vertical, and finally landing.

IMHO the Astra rocket was using differential, and as such it needs to have a thrust overhead for positive authority over pitch and yaw. I have attached the normal configuration of forces around one of the control axis, and what happens when we lose an engine.

It seems evident that the two engines closes to the axis have a hard time to overcome the thrust exerted by the other two engines further away. In order not to topple, the guidance system would need to leave the thrust of engines 3 & 4 at their present level, and increase thrust on 2 & 5 to the maximum afforded by the differential control overhead. Slowly but surely, lateral motion is cancelled out, leading to the ability to increase thrust on 2 & 5 again, increasing rate of ascent.

I could be totally off-piste here, I'll let the experts tell me I'm a idiot :-)
No. Full 2 axis gimbal and not differential.

Differential is a bad idea for multiple reasons.

No they can certainly gimbal in all directions.

Not that they need to of course. 1-axis of gimbal on a ring of only 3 engines would be enough to give you full control. It's just as possible with a ring of 5, although I imagine the TVC programming would be pretty annoying.

And not resilient to an engine out worth a damn!

Plenty resilient on the TVC front. In principle you could lose 3 engines and still have total control in every axis. The programming would be a nightmare, and your control margins will still be tiny, but in terms of the physics it's an option.
« Last Edit: 09/04/2021 07:40 am by JEF_300 »
Wait, ∆V? This site will accept the ∆ symbol? How many times have I written out the word "delta" for no reason?

Offline LouScheffer

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Plenty resilient on the TVC front. In principle you could lose 3 engines and still have total control in every axis. The programming would be a nightmare, and your control margins will still be tiny, but in terms of the physics it's an option.
The programming should be much easier then the all-engines available case.  You have two vectors you can choose, and they need to sum to a third vector.  There's no ambiguity - it's two equations in two unknowns.   In the regular case, you have many more variables than you need, and you have to pick one solution among many, optimizing for other constraints.  It's a much harder math problem.

Offline FlatFootShift

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Any update on when a next launch is being planned for?

Online TrevorMonty

Its little details that matter, like engines that run till MECO.

https://twitter.com/Astra/status/1435987623902842883?s=19

Sent from my SM-G570Y using Tapatalk
« Last Edit: 09/09/2021 05:36 pm by TrevorMonty »

Offline edkyle99

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Firefly has kept the public informed about the broad path of its early-engine-shut-down investigation.  Anything from Astra on its somewhat similar issue?

 - Ed Kyle

Offline harrystranger

Imagery from Sentinel-2 shows the scar left by Rocket 3.3 as it did it's slide off of the pad. Comparison in the gif attached below  :)
Measured to be ~80m long.
It can be really hard to interpret satellite imagery! Local knowledge & an understanding of an area’s history are crucial pieces of the puzzle.
- Rob Simmon

Offline Comga

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So Firefly got up 50,000 ft without getting offshore and Astra got offshore without gaining any altitude.

We could suggest they collaborate but the combination might be a pad explosion.
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline Chris Bergin

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