[Merged] SpaceX’s Starship Rocket Explodes After Launch/Starship hop - Page 2

crescent · 9th December 2020, 03:48 PM

Originally Posted by 3point14

Wow.

It blew up - but not until it was done. And it did the thing with the engines, and going sideways, and belly flopping, then back up right again.

That was crazy.

3point14 · 9th December 2020, 03:52 PM

And it 'landed' where they wanted it to.

I suspect that's as much success as they could hope for.

SN9 is just over there, they have a metric ****ton of data to apply to the next go.

cow_cat · 9th December 2020, 04:05 PM

Fare the well, SN8. You gave us good data, burning fairings, beautiful gimbaling recovering raptors, perfect belly flop, an incredible relight manouevre (2 out of 3 ain't bad) then an epic explosion. Mission absolutely accomplished.

smartcooky · 9th December 2020, 04:15 PM

Rocket go BOOM!

Garrison · 9th December 2020, 04:18 PM

Amazing flight and Elon Musk has tweeted that the problem was low pressure in the LOX header tank that lead to reduced thrust in the final stages, so I imagine a few tweaks will be made, the pad will be cleaned up and SN09 will move out, and any more extensive mods will go into SN10 and 11, got to love rapid prototyping.

casebro · 9th December 2020, 06:59 PM

Is he launching from The Interplanetary House Of Pancakes?

a_unique_person · 9th December 2020, 07:34 PM

Originally Posted by cow_cat

Fare the well, SN8. You gave us good data, burning fairings, beautiful gimbaling recovering raptors, perfect belly flop, an incredible relight manouevre (2 out of 3 ain't bad) then an epic explosion. Mission absolutely accomplished.

Epic explosion FTW.

smartcooky · 9th December 2020, 07:42 PM

Tweet from Elon Musk

"Successful ascent, switchover to header tanks & precise flap control to landing point!"

"Fuel header tank pressure was low during landing burn, causing touchdown velocity to be high & RUD, but we got all the data we needed! Congrats SpaceX team hell yeah!!"

I will be watching for Scott Manley's take on today's events

angrysoba · 9th December 2020, 08:12 PM

Chuck Yaeger would not have approved of the landing, but probably not too bad beyond that.

Could someone tell me what was going on with the engine that appeared loose? Was that by design or is that essentially the cause of the problem?

https://youtu.be/ap-BkkrRg-o?t=6601

a_unique_person · 9th December 2020, 08:25 PM

They are on gimbals.

angrysoba · 9th December 2020, 08:28 PM

Originally Posted by a_unique_person

They are on gimbals.

Thanks!

a_unique_person · 9th December 2020, 09:54 PM

My take on this. Everything worked perfectly up to the last minute, which created a spectacular fireball. Accident? I don't think so.

smartcooky · 9th December 2020, 11:38 PM

Originally Posted by angrysoba

Chuck Yaeger would not have approved of the landing, but probably not too bad beyond that.

Could someone tell me what was going on with the engine that appeared loose? Was that by design or is that essentially the cause of the problem?

https://youtu.be/ap-BkkrRg-o?t=6601

Here is the reason, as I understand it.

At this stage of development, the methalox powered Raptor engines can only be throttled down to 40% of maximum thrust, but the test was designed to take the rocket to a specific height, pitch it over and let it fall back to earth. Rather than throttle back the engines, they decided to shut down first one, then two then three engines to slow down and eventually stop the ascent

If you watch closely, at about T+1:40, the whole three engines gimbal to the bottom right of the picture just before the first engine (top left) gimbals outwards as it shuts down. This is done in order to reduce the sideways thrust as the two remaining running engines gimbal sharply to the centre to maintain the correct attitude. Same thing happens again at T+3:12 when the second engine shuts down. You can see that both the shut down engine nozzles are gimballed well away from centre to give the running engine a full range of movement.

You can see that all three nozzles have gimballed back to centre by the time the landing burn happened at T+6:30 with all three engines lighting

smartcooky · 10th December 2020, 01:25 AM

And FYI, here is Scott Manley on today's test, which includes an awesome view from the landing pad camera looking straight up at the rocket bellyflopping and flipping just before it crashes.

https://www.youtube.com/watch?v=egHxiX40eJY

a_unique_person · 10th December 2020, 01:42 AM

So they try, first time, get this to land on the landing pad, right in the middle of the Boca Chita site.

smartcooky · 10th December 2020, 01:53 AM

Originally Posted by a_unique_person

So they try, first time, get this to land on the landing pad, right in the middle of the Boca Chita site.

Err, no! The launch pad is about two miles ENE of the main site where the control rooms and rocket build centre is

angrysoba · 10th December 2020, 04:14 AM

Originally Posted by smartcooky

Here is the reason, as I understand it.

At this stage of development, the methalox powered Raptor engines can only be throttled down to 40% of maximum thrust, but the test was designed to take the rocket to a specific height, pitch it over and let it fall back to earth. Rather than throttle back the engines, they decided to shut down first one, then two then three engines to slow down and eventually stop the ascent

If you watch closely, at about T+1:40, the whole three engines gimbal to the bottom right of the picture just before the first engine (top left) gimbals outwards as it shuts down. This is done in order to reduce the sideways thrust as the two remaining running engines gimbal sharply to the centre to maintain the correct attitude. Same thing happens again at T+3:12 when the second engine shuts down. You can see that both the shut down engine nozzles are gimballed well away from centre to give the running engine a full range of movement.

You can see that all three nozzles have gimballed back to centre by the time the landing burn happened at T+6:30 with all three engines lighting

Thanks for that!

cjameshuff · 10th December 2020, 05:36 AM

Originally Posted by Garrison

Amazing flight and Elon Musk has tweeted that the problem was low pressure in the LOX header tank that lead to reduced thrust in the final stages, so I imagine a few tweaks will be made, the pad will be cleaned up and SN09 will move out, and any more extensive mods will go into SN10 and 11, got to love rapid prototyping.

Fuel header, not the LOX header.
The fuel also being the coolant for the engines and the thing that keeps the oxygen from eating them, which is why that last engine was so unhappy.

crescent · 10th December 2020, 08:19 AM

I thought the "bellyflop" thing was just so "meh!" - I mean they were just totally ripping off the "Adama maneuver from Battlestar Galactica:

YouTube Video This video is not hosted by the ISF. The ISF can not be held responsible for the suitability or legality of this material. By clicking the link below you agree to view content from an external website.

I AGREE

(skip to 1:43 for the relevant part)

Garrison · 10th December 2020, 10:42 AM

Originally Posted by cjameshuff

Fuel header, not the LOX header.
The fuel also being the coolant for the engines and the thing that keeps the oxygen from eating them, which is why that last engine was so unhappy.

My bad. Important thing is they were able to pin down the problem right away.

cjameshuff · 10th December 2020, 10:58 AM

Originally Posted by Garrison

My bad. Important thing is they were able to pin down the problem right away.

Wouldn't surprise me if they had someone watching a line on a plot dip and going "uh-oh" as it happened.

arthwollipot · 10th December 2020, 04:38 PM

Originally Posted by crescent

It blew up - but not until it was done. And it did the thing with the engines, and going sideways, and belly flopping, then back up right again.

That was crazy.

My reaction was that 7 out of 8 criteria for success were met.

Launch successfully - tick
Climb to target altitude - tick
Transition to bellyflop position - tick
Controlled descent - tick
Transition to upright position - tick
Relight engines - tick
On target to landing site - tick
Land without exploding -

a_unique_person · 10th December 2020, 06:43 PM

What's it like for the people in the Starship when it does the aerobatics?

arthwollipot · 10th December 2020, 06:46 PM

Originally Posted by a_unique_person

What's it like for the people in the Starship when it does the aerobatics?

It's not especially aerobatic. Particularly when you consider that on a genuine mission, the craft would approach the atmosphere pretty much already in the bellyflop position, and the only manoeuvring required is the transition to upright just before landing. It'll be rough, but not too bad.

smartcooky · 10th December 2020, 06:54 PM

Originally Posted by arthwollipot

My reaction was that 7 out of 8 criteria for success were met.

Launch successfully - tick
Climb to target altitude - tick
Transition to bellyflop position - tick
Controlled descent - tick
Transition to upright position - tick
Relight engines - tick
On target to landing site - tick
Land without exploding -

A couple of other things it did that were important...

1A. Synchronized engine shutdowns and gimbaling to maintain the vehicle attitude during ascent.
1B. Translation while maintaining attitude to prepare for the pitch-over maneuver at target altitude (the vehicle needed to get "downrange" in order to pitch over and glide/skydive back to the landing pad)

arthwollipot · 10th December 2020, 06:55 PM

Originally Posted by smartcooky

A couple of other things it did that were important...

1A. Synchronized engine shutdowns and gimbaling to maintain the vehicle attitude during ascent.
1B. Translation while maintaining attitude to prepare for the pitch-over maneuver at target altitude (the vehicle needed to get "downrange" in order to pitch over and glide/skydive back to the landing pad)

Indeed. So let's say 9/10 criteria for success.

smartcooky · 11th December 2020, 10:51 AM

SN9 has tipped over in the high bay and is leaning against one corner. Happened about 9:02am Friday morning.

https://twitter.com/BocaChicaGal/sta...24248260993024

Looks like a stand might have buckled.

Trebuchet · 11th December 2020, 12:06 PM

Originally Posted by arthwollipot

My reaction was that 7 out of 8 criteria for success were met.

Launch successfully - tick
Climb to target altitude - tick
Transition to bellyflop position - tick
Controlled descent - tick
Transition to upright position - tick
Relight engines - tick
On target to landing site - tick
Land without exploding -

Not sure I'd give the tick on "relight engines". Yes they relit, but then began consuming themselves.

Mike! · 11th December 2020, 12:13 PM

Originally Posted by a_unique_person

What's it like for the people in the Starship when it does the aerobatics?

Probably not nearly as rough as on them as it is when it blows up.

cjameshuff · 11th December 2020, 12:35 PM

Originally Posted by Trebuchet

Not sure I'd give the tick on "relight engines". Yes they relit, but then began consuming themselves.

They got the vehicle oriented and a good way to the pad before they started having issues. The low fuel header pressure issues only had a visible effect a good bit after ignition, and if they were present at ignition the Raptors only deserve extra credit for successfully igniting under suboptimal conditions.

wardenclyffe · 11th December 2020, 12:46 PM

Can anyone link to a video where there is NOT an edit in the split second before the explosion?

Ward

3point14 · 11th December 2020, 01:00 PM

Originally Posted by Trebuchet

Not sure I'd give the tick on "relight engines". Yes they relit, but then began consuming themselves.

They re-lit. They just had burned a bit engine rich.

Garrison · 11th December 2020, 01:27 PM

Originally Posted by smartcooky

SN9 has tipped over in the high bay and is leaning against one corner. Happened about 9:02am Friday morning.

https://twitter.com/BocaChicaGal/sta...24248260993024

Looks like a stand might have buckled.

Well damn, but its stainless steel so replacing parts should be straightforward, unlike the Orion capsule where a PDU failure could take months to repair:

https://www.theverge.com/2020/11/30/...lure-artemis-i

Garrison · 11th December 2020, 04:34 PM

Bad news is the tilt damaged a fin, good news a replacement fin arrived within a few hours.

smartcooky · 11th December 2020, 05:11 PM

Originally Posted by Trebuchet

Not sure I'd give the tick on "relight engines". Yes they relit, but then began consuming themselves.

That was because of fuel starvation due to low pressure in the header tank, not a problem with the engine.

Lack of fuel causes the engines to run "Oxidizer Rich". AIUI (no doubt Jay will correct me if I'm wrong) when that happens, the oxygen will be chemically reacting with the best available candidate. Since the Raptor combustion chamber and nozzle contains copper, it will combine with that. This will cause the chamber temperature to spike, and since pure oxygen is very corrosive at high temperatures, the copper gets rapidly oxidized away, causing the bright green flame we saw.

The resulting sudden drop in thrust meant that the rocket fell too quickly to get fully upright and land safely.

cjameshuff · 11th December 2020, 05:21 PM

Originally Posted by smartcooky

That was because of fuel starvation due to low pressure in the header tank, not a problem with the engine.

Lack of fuel causes the engines to run "Oxidizer Rich". AIUI (no doubt Jay will correct me if I'm wrong) when that happens, the oxygen will be chemically reacting with the best available candidate. Since the Raptor combustion chamber and nozzle contains copper, it will combine with that. This will cause the chamber temperature to spike, and since pure oxygen is very corrosive at high temperatures, the copper gets rapidly oxidized away, causing the bright green flame we saw.

The resulting sudden drop in thrust meant that the rocket fell too quickly to get fully upright and land safely.

The fuel's also the coolant that keeps them from melting under normal operating conditions.

smartcooky · 11th December 2020, 06:46 PM

Originally Posted by cjameshuff

The fuel's also the coolant that keeps them from melting under normal operating conditions.

Yes, I forgot that. The lack of liquid methane flow was probably the key factor in the engine temperature spiking.

Garrison · 26th December 2020, 07:42 AM

Short video covering the fates of SN01-SN08:

https://www.youtube.com/watch?v=G7Ik089A5nc

From cryo tank test to 12.5km flight test took 10 months.

Trebuchet · 26th December 2020, 11:04 AM

I note that S/N Nine, or Snine as I think of it, has had engines installed without first doing the pressure test with artificial thrust simulator. Definitely moving right along.

Mader Levap · 26th December 2020, 04:48 PM

Originally Posted by smartcooky

SSTO might be possible, but I doubt such a vehicle would or could deliver a significant payload to orbit.

SSTO is already possible. It is just so uneconomical with current tech that no one bothers with it.

9th December 2020, 03:52 PM	#42
3point14 Pi Join Date: Nov 2005 Posts: 21,734	And it 'landed' where they wanted it to. I suspect that's as much success as they could hope for. SN9 is just over there, they have a metric ****ton of data to apply to the next go.
3point14 Pi Join Date: Nov 2005 Posts: 21,734	__________________ Up the River! Anyone that wraps themselves in the Union Flag and also lives in tax exile is a [redacted]

9th December 2020, 04:05 PM	#43
cow_cat Mr. Parodied Join Date: Feb 2006 Location: Between the Sun and the Stars Posts: 2,572	Fare the well, SN8. You gave us good data, burning fairings, beautiful gimbaling recovering raptors, perfect belly flop, an incredible relight manouevre (2 out of 3 ain't bad) then an epic explosion. Mission absolutely accomplished.
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9th December 2020, 04:15 PM	#44
smartcooky Penultimate Amazing Join Date: Oct 2012 Location: Nelson, New Zealand Posts: 24,829	Rocket go BOOM!
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9th December 2020, 04:18 PM	#45
Garrison Philosopher Join Date: Sep 2011 Location: UK Posts: 6,101	Amazing flight and Elon Musk has tweeted that the problem was low pressure in the LOX header tank that lead to reduced thrust in the final stages, so I imagine a few tweaks will be made, the pad will be cleaned up and SN09 will move out, and any more extensive mods will go into SN10 and 11, got to love rapid prototyping.
	__________________ So I've started a blog about my writing. Check it out at: http://fourth-planet-problem.blogspot.com/ And my first book is on Amazon: https://www.amazon.com/dp/B077W322FX

9th December 2020, 06:59 PM	#46
casebro Penultimate Amazing Join Date: Jun 2005 Posts: 19,788	Is he launching from The Interplanetary House Of Pancakes?
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9th December 2020, 03:48 PM	#41
crescent Philosopher Join Date: Jul 2011 Location: Colorado Posts: 5,591	Originally Posted by 3point14 Wow. It blew up - but not until it was done. And it did the thing with the engines, and going sideways, and belly flopping, then back up right again. That was crazy.

9th December 2020, 07:34 PM	#47
a_unique_person Director of Hatcheries and Conditioning Join Date: Jul 2002 Location: Waiting for the pod bay door to open. Posts: 46,005	Originally Posted by cow_cat Fare the well, SN8. You gave us good data, burning fairings, beautiful gimbaling recovering raptors, perfect belly flop, an incredible relight manouevre (2 out of 3 ain't bad) then an epic explosion. Mission absolutely accomplished. Epic explosion FTW.
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9th December 2020, 07:42 PM	#48
smartcooky Penultimate Amazing Join Date: Oct 2012 Location: Nelson, New Zealand Posts: 24,829	Tweet from Elon Musk "Successful ascent, switchover to header tanks & precise flap control to landing point!" "Fuel header tank pressure was low during landing burn, causing touchdown velocity to be high & RUD, but we got all the data we needed! Congrats SpaceX team hell yeah!!" I will be watching for Scott Manley's take on today's events
	__________________ Those who claim that something can't be done need to stop getting in the way of those who are actually doing it! - Anonymous Its TRE45ON season... convict the F45CIST!!

9th December 2020, 08:12 PM	#49
angrysoba Philosophile Join Date: Dec 2009 Location: Osaka, Japan Posts: 35,278	Chuck Yaeger would not have approved of the landing, but probably not too bad beyond that. Could someone tell me what was going on with the engine that appeared loose? Was that by design or is that essentially the cause of the problem? https://youtu.be/ap-BkkrRg-o?t=6601
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9th December 2020, 08:25 PM	#50
a_unique_person Director of Hatcheries and Conditioning Join Date: Jul 2002 Location: Waiting for the pod bay door to open. Posts: 46,005	They are on gimbals.
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9th December 2020, 08:28 PM	#51
angrysoba Philosophile Join Date: Dec 2009 Location: Osaka, Japan Posts: 35,278	Originally Posted by a_unique_person They are on gimbals. Thanks!
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9th December 2020, 09:54 PM	#52
a_unique_person Director of Hatcheries and Conditioning Join Date: Jul 2002 Location: Waiting for the pod bay door to open. Posts: 46,005	My take on this. Everything worked perfectly up to the last minute, which created a spectacular fireball. Accident? I don't think so.
	__________________ *Continually pushing the boundaries of mediocrity.* Everything is possible, but not everything is probable. “Perception is real, but the truth is not.” - Imelda Marcos

9th December 2020, 11:38 PM	#53
smartcooky Penultimate Amazing Join Date: Oct 2012 Location: Nelson, New Zealand Posts: 24,829	Originally Posted by angrysoba Chuck Yaeger would not have approved of the landing, but probably not too bad beyond that. Could someone tell me what was going on with the engine that appeared loose? Was that by design or is that essentially the cause of the problem? https://youtu.be/ap-BkkrRg-o?t=6601 Here is the reason, as I understand it. At this stage of development, the methalox powered Raptor engines can only be throttled down to 40% of maximum thrust, but the test was designed to take the rocket to a specific height, pitch it over and let it fall back to earth. Rather than throttle back the engines, they decided to shut down first one, then two then three engines to slow down and eventually stop the ascent If you watch closely, at about T+1:40, the whole three engines gimbal to the bottom right of the picture just before the first engine (top left) gimbals outwards as it shuts down. This is done in order to reduce the sideways thrust as the two remaining running engines gimbal sharply to the centre to maintain the correct attitude. Same thing happens again at T+3:12 when the second engine shuts down. You can see that both the shut down engine nozzles are gimballed well away from centre to give the running engine a full range of movement. You can see that all three nozzles have gimballed back to centre by the time the landing burn happened at T+6:30 with all three engines lighting
	__________________ Those who claim that something can't be done need to stop getting in the way of those who are actually doing it! - Anonymous Its TRE45ON season... convict the F45CIST!!

10th December 2020, 01:25 AM	#54
smartcooky Penultimate Amazing Join Date: Oct 2012 Location: Nelson, New Zealand Posts: 24,829	And FYI, here is Scott Manley on today's test, which includes an awesome view from the landing pad camera looking straight up at the rocket bellyflopping and flipping just before it crashes. https://www.youtube.com/watch?v=egHxiX40eJY
	__________________ Those who claim that something can't be done need to stop getting in the way of those who are actually doing it! - Anonymous Its TRE45ON season... convict the F45CIST!!

10th December 2020, 01:42 AM	#55
a_unique_person Director of Hatcheries and Conditioning Join Date: Jul 2002 Location: Waiting for the pod bay door to open. Posts: 46,005	So they try, first time, get this to land on the landing pad, right in the middle of the Boca Chita site.
	__________________ *Continually pushing the boundaries of mediocrity.* Everything is possible, but not everything is probable. “Perception is real, but the truth is not.” - Imelda Marcos

10th December 2020, 01:53 AM	#56
smartcooky Penultimate Amazing Join Date: Oct 2012 Location: Nelson, New Zealand Posts: 24,829	Originally Posted by a_unique_person So they try, first time, get this to land on the landing pad, right in the middle of the Boca Chita site. Err, no! The launch pad is about two miles ENE of the main site where the control rooms and rocket build centre is
	__________________ Those who claim that something can't be done need to stop getting in the way of those who are actually doing it! - Anonymous Its TRE45ON season... convict the F45CIST!! Last edited by smartcooky; 10th December 2020 at 02:02 AM.

10th December 2020, 04:14 AM	#57
angrysoba Philosophile Join Date: Dec 2009 Location: Osaka, Japan Posts: 35,278	Originally Posted by smartcooky Here is the reason, as I understand it. At this stage of development, the methalox powered Raptor engines can only be throttled down to 40% of maximum thrust, but the test was designed to take the rocket to a specific height, pitch it over and let it fall back to earth. Rather than throttle back the engines, they decided to shut down first one, then two then three engines to slow down and eventually stop the ascent If you watch closely, at about T+1:40, the whole three engines gimbal to the bottom right of the picture just before the first engine (top left) gimbals outwards as it shuts down. This is done in order to reduce the sideways thrust as the two remaining running engines gimbal sharply to the centre to maintain the correct attitude. Same thing happens again at T+3:12 when the second engine shuts down. You can see that both the shut down engine nozzles are gimballed well away from centre to give the running engine a full range of movement. You can see that all three nozzles have gimballed back to centre by the time the landing burn happened at T+6:30 with all three engines lighting Thanks for that!
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10th December 2020, 05:36 AM	#58
cjameshuff Critical Thinker Join Date: Feb 2013 Posts: 370	Originally Posted by Garrison Amazing flight and Elon Musk has tweeted that the problem was low pressure in the LOX header tank that lead to reduced thrust in the final stages, so I imagine a few tweaks will be made, the pad will be cleaned up and SN09 will move out, and any more extensive mods will go into SN10 and 11, got to love rapid prototyping. Fuel header, not the LOX header. The fuel also being the coolant for the engines and the thing that keeps the oxygen from eating them, which is why that last engine was so unhappy.

10th December 2020, 10:42 AM	#60
Garrison Philosopher Join Date: Sep 2011 Location: UK Posts: 6,101	Originally Posted by cjameshuff Fuel header, not the LOX header. The fuel also being the coolant for the engines and the thing that keeps the oxygen from eating them, which is why that last engine was so unhappy. My bad. Important thing is they were able to pin down the problem right away.
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10th December 2020, 10:58 AM	#61
cjameshuff Critical Thinker Join Date: Feb 2013 Posts: 370	Originally Posted by Garrison My bad. Important thing is they were able to pin down the problem right away. Wouldn't surprise me if they had someone watching a line on a plot dip and going "uh-oh" as it happened.

10th December 2020, 04:38 PM	#62
arthwollipot Observer of Phenomena Pronouns: he/him Join Date: Feb 2005 Location: Ngunnawal Country Posts: 85,474	Originally Posted by crescent It blew up - but not until it was done. And it did the thing with the engines, and going sideways, and belly flopping, then back up right again. That was crazy. My reaction was that 7 out of 8 criteria for success were met. Launch successfully - tick Climb to target altitude - tick Transition to bellyflop position - tick Controlled descent - tick Transition to upright position - tick Relight engines - tick On target to landing site - tick Land without exploding -
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10th December 2020, 06:43 PM	#63
a_unique_person Director of Hatcheries and Conditioning Join Date: Jul 2002 Location: Waiting for the pod bay door to open. Posts: 46,005	What's it like for the people in the Starship when it does the aerobatics?
	__________________ *Continually pushing the boundaries of mediocrity.* Everything is possible, but not everything is probable. “Perception is real, but the truth is not.” - Imelda Marcos

10th December 2020, 06:46 PM	#64
arthwollipot Observer of Phenomena Pronouns: he/him Join Date: Feb 2005 Location: Ngunnawal Country Posts: 85,474	Originally Posted by a_unique_person What's it like for the people in the Starship when it does the aerobatics? It's not especially aerobatic. Particularly when you consider that on a genuine mission, the craft would approach the atmosphere pretty much already in the bellyflop position, and the only manoeuvring required is the transition to upright just before landing. It'll be rough, but not too bad.
	__________________ A million people can call the mountains a fiction Yet it need not trouble you as you stand atop them https://xkcd.com/154/

10th December 2020, 06:54 PM	#65
smartcooky Penultimate Amazing Join Date: Oct 2012 Location: Nelson, New Zealand Posts: 24,829	Originally Posted by arthwollipot My reaction was that 7 out of 8 criteria for success were met. Launch successfully - tick Climb to target altitude - tick Transition to bellyflop position - tick Controlled descent - tick Transition to upright position - tick Relight engines - tick On target to landing site - tick Land without exploding - A couple of other things it did that were important... 1A. Synchronized engine shutdowns and gimbaling to maintain the vehicle attitude during ascent. 1B. Translation while maintaining attitude to prepare for the pitch-over maneuver at target altitude (the vehicle needed to get "downrange" in order to pitch over and glide/skydive back to the landing pad)
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10th December 2020, 06:55 PM	#66
arthwollipot Observer of Phenomena Pronouns: he/him Join Date: Feb 2005 Location: Ngunnawal Country Posts: 85,474	Originally Posted by smartcooky A couple of other things it did that were important... 1A. Synchronized engine shutdowns and gimbaling to maintain the vehicle attitude during ascent. 1B. Translation while maintaining attitude to prepare for the pitch-over maneuver at target altitude (the vehicle needed to get "downrange" in order to pitch over and glide/skydive back to the landing pad) Indeed. So let's say 9/10 criteria for success.
	__________________ A million people can call the mountains a fiction Yet it need not trouble you as you stand atop them https://xkcd.com/154/

11th December 2020, 10:51 AM	#67
smartcooky Penultimate Amazing Join Date: Oct 2012 Location: Nelson, New Zealand Posts: 24,829	SN9 has tipped over in the high bay and is leaning against one corner. Happened about 9:02am Friday morning. https://twitter.com/BocaChicaGal/sta...24248260993024 Looks like a stand might have buckled.
	__________________ Those who claim that something can't be done need to stop getting in the way of those who are actually doing it! - Anonymous Its TRE45ON season... convict the F45CIST!!

11th December 2020, 12:06 PM	#68
Trebuchet Penultimate Amazing Join Date: Nov 2003 Location: Port Townsend, Washington Posts: 38,281	Originally Posted by arthwollipot My reaction was that 7 out of 8 criteria for success were met. Launch successfully - tick Climb to target altitude - tick Transition to bellyflop position - tick Controlled descent - tick Transition to upright position - tick Relight engines - tick On target to landing site - tick Land without exploding - Not sure I'd give the tick on "relight engines". Yes they relit, but then began consuming themselves.
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11th December 2020, 12:13 PM	#69
Mike! Official Ponylandistanian National Treasure. Respect it! Join Date: May 2010 Location: Ponylandistan! Where the bacon grows on trees! Can it get any better than that? I submit it can not! Posts: 52,011	Originally Posted by a_unique_person What's it like for the people in the Starship when it does the aerobatics? Probably not nearly as rough as on them as it is when it blows up.
	__________________ "Never judge a man until you’ve walked a mile in his shoes... Because then it won't really matter, you’ll be a mile away and have his shoes."

11th December 2020, 12:35 PM	#70
cjameshuff Critical Thinker Join Date: Feb 2013 Posts: 370	Originally Posted by Trebuchet Not sure I'd give the tick on "relight engines". Yes they relit, but then began consuming themselves. They got the vehicle oriented and a good way to the pad before they started having issues. The low fuel header pressure issues only had a visible effect a good bit after ignition, and if they were present at ignition the Raptors only deserve extra credit for successfully igniting under suboptimal conditions.

11th December 2020, 12:46 PM	#71
wardenclyffe Master Poster Join Date: Dec 2008 Posts: 2,333	Can anyone link to a video where there is NOT an edit in the split second before the explosion? Ward
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11th December 2020, 01:00 PM	#72
3point14 Pi Join Date: Nov 2005 Posts: 21,734	Originally Posted by Trebuchet Not sure I'd give the tick on "relight engines". Yes they relit, but then began consuming themselves. They re-lit. They just had burned a bit engine rich.
3point14 Pi Join Date: Nov 2005 Posts: 21,734	__________________ Up the River! Anyone that wraps themselves in the Union Flag and also lives in tax exile is a [redacted]

11th December 2020, 01:27 PM	#73
Garrison Philosopher Join Date: Sep 2011 Location: UK Posts: 6,101	Originally Posted by smartcooky SN9 has tipped over in the high bay and is leaning against one corner. Happened about 9:02am Friday morning. https://twitter.com/BocaChicaGal/sta...24248260993024 Looks like a stand might have buckled. Well damn, but its stainless steel so replacing parts should be straightforward, unlike the Orion capsule where a PDU failure could take months to repair: https://www.theverge.com/2020/11/30/...lure-artemis-i
	__________________ So I've started a blog about my writing. Check it out at: http://fourth-planet-problem.blogspot.com/ And my first book is on Amazon: https://www.amazon.com/dp/B077W322FX

11th December 2020, 04:34 PM	#74
Garrison Philosopher Join Date: Sep 2011 Location: UK Posts: 6,101	Bad news is the tilt damaged a fin, good news a replacement fin arrived within a few hours.
	__________________ So I've started a blog about my writing. Check it out at: http://fourth-planet-problem.blogspot.com/ And my first book is on Amazon: https://www.amazon.com/dp/B077W322FX

11th December 2020, 05:11 PM	#75
smartcooky Penultimate Amazing Join Date: Oct 2012 Location: Nelson, New Zealand Posts: 24,829	Originally Posted by Trebuchet Not sure I'd give the tick on "relight engines". Yes they relit, but then began consuming themselves. That was because of fuel starvation due to low pressure in the header tank, not a problem with the engine. Lack of fuel causes the engines to run "Oxidizer Rich". AIUI (no doubt Jay will correct me if I'm wrong) when that happens, the oxygen will be chemically reacting with the best available candidate. Since the Raptor combustion chamber and nozzle contains copper, it will combine with that. This will cause the chamber temperature to spike, and since pure oxygen is very corrosive at high temperatures, the copper gets rapidly oxidized away, causing the bright green flame we saw. The resulting sudden drop in thrust meant that the rocket fell too quickly to get fully upright and land safely.
	__________________ Those who claim that something can't be done need to stop getting in the way of those who are actually doing it! - Anonymous Its TRE45ON season... convict the F45CIST!! Last edited by smartcooky; 11th December 2020 at 05:14 PM.

11th December 2020, 05:21 PM	#76
cjameshuff Critical Thinker Join Date: Feb 2013 Posts: 370	Originally Posted by smartcooky That was because of fuel starvation due to low pressure in the header tank, not a problem with the engine. Lack of fuel causes the engines to run "Oxidizer Rich". AIUI (no doubt Jay will correct me if I'm wrong) when that happens, the oxygen will be chemically reacting with the best available candidate. Since the Raptor combustion chamber and nozzle contains copper, it will combine with that. This will cause the chamber temperature to spike, and since pure oxygen is very corrosive at high temperatures, the copper gets rapidly oxidized away, causing the bright green flame we saw. The resulting sudden drop in thrust meant that the rocket fell too quickly to get fully upright and land safely. The fuel's also the coolant that keeps them from melting under normal operating conditions.