FAILURE: Relativity Terran 1 Test Flight : CCSFS SLC-16 : 23 Mar 2023 03:25 UTC

[butters]

Not to be a party pooper, but when was the last time ANY rocket failed at Max-Q?  Everyone calls it out, but everyone seems to pass through it without issue.

The forces seem pretty straightforward to compute, and/or measure in a wind tunnel, and surely the ground structural test reproduces those forces quite closely (as opposed to other events that can only be replicated in flight, like second engine ignition after staging).  So the margins should be known as well.

So I'm sure it still makes the structural folks nervous, but the odds of failure due to forces at Max-Q seem pretty low (and especially after the first flight, after all the forces and vehicle responses are measure in practice).  It seems as if it's there for historical reasons (everyone else mentions it) and it helps the hosts fill the air time between launch and staging.

See: SpaceX removing payload bay functionality from several Starships down the production line. It would appear that multiple mistakes were made in calculating aerodynamic stresses on unpressurized sections of Starship prior to physical testing.

Western satellites can no longer be launched on Chinese rockets because of incidents in the 1990s when Western aerospace companies were trying to help China stop their payload fairings from failing near max-q.

The fact that modern rockets rarely get crushed by aerodynamic pressure is a testament to the level of care that's typically put into making sure that won't happen. As commercial launch providers push the envelope of rapid iteration to increase development rate and drive down costs, the risks of not discovering a structural deficiency before launch are increased, and deficiencies may be discovered later in the development cycle than they would have under more conservative program management.

[GWH]

The webcast host losing it at MaxQ and screaming into the mic was beautiful and brought a tear to my eye! Love the passion and excitement of their team!

I could not disagree more. It was both unprofessional and annoying. Sure pipe in some audio from a happy team, but maintain some professionalism by the hosts. It was an excellent webcast (and a very successful test) ruined by the hosts. Suppose it's an American thing.

I’m sorry people who likely worked months if not years on this thing are expressing their excitement to the world. These hosts did amazing, and you hating on them shows how little you probably care for people behind the scenes. Get some respect.

Two highly educated and deeply involved female engineers screaming like little girls on the playground as their rocket pushes past Max-Q!

I can't imagine a better image for a company that is completely reimagining what it is to be a successful aerospace company.

Exactly. That kind of enthusiasm and passion is what a young cutting edge company needs to push through the long grind required. Of course they should learn to contain their excitement as they gain more practice - just as the whole company needs to practice and learn as they work towards carrying customer payloads.

But right now they need that enthusiasm - not a stodgy group of individuals who are so measured and controlled that they're incapable of pushing boundaries.  If that's an "American thing" then the direct contrast would be Arianespace with their dull and uninspired webcast hosts: a perfect reflection of their dull and uninspired rocket that's not only years late but was already obsolete the day the concept was finalized.

[Steve G]

I loved the telecast and the emotion and transparency. They were delighted just to get the rocket out of sight, and honest when the video showed the second stage's sputtering engine and declining speed when they'd wait for the callout on the second stage engine. I don't know what's up with upper stage failures on new rockets, but this is something like the fifth consecutive launch failure due to the "cursed second stage syndrome". My only suggestion is that all commentators watch the Apollo launches and learn from the "Great One", Jack King.

[FutureSpaceTourist]

https://twitter.com/thetimellis/status/1638985593580408841

🚀🤯🥹😭🤘🌌 stunning and visceral first launch, what a first to witness

[punder]

I loved the telecast and the emotion and transparency. They were delighted just to get the rocket out of sight, and honest when the video showed the second stage's sputtering engine and declining speed when they'd wait for the callout on the second stage engine. I don't know what's up with upper stage failures on new rockets, but this is something like the fifth consecutive launch failure due to the "cursed second stage syndrome". My only suggestion is that all commentators watch the Apollo launches and learn from the "Great One", Jack King.

I don't like all the emoting and yelling either (same complaint with the only slightly more restrained Blue Origin launches) but... who the heck cares? More power to 'em.

That was a beautiful launch by the way. Methane is going to make for some awesome launch photography. What am I saying, it already has.

[Robert_the_Doll]

Scott Manley gives us his usual astute commentary:

[edkyle99]

The webcast host losing it at MaxQ and screaming into the mic was beautiful and brought a tear to my eye! Love the passion and excitement of their team!

I could not disagree more. It was both unprofessional and annoying. Sure pipe in some audio from a happy team, but maintain some professionalism by the hosts. It was an excellent webcast (and a very successful test) ruined by the hosts. Suppose it's an American thing.

When Ranger 7 finally hit the moon, journalists at JPL whoooped and threw papers in the air and jumped up and down and SHOUTED. 

Ole Walter Cronkite himself yelled "Oh, Go baby", while he hopped around, at John Glenn's rising Atlas.  He shouted and shouted during the first Saturn 5 launch, overwhelmed by the earthquake forces at play.  He shed tears -  on live TV - when Apollo 11 landed on the Moon.     

Shouting and oohing and aahing during a launch.  I did that more than once -  while I was a nerd engineer working at KSC!  When Challenger blew up in front of my eyes I fell to the ground.  These things are powerful, and dramatic, and real.

 - Ed Kyle

[OneSpeed]

Here is a plot of the webcast telemetry from the Terran 1 test flight. The data stream was quite choppy, and the three largest spikes in acceleration are due to freezes in the stream.

Nevertheless, it is clear from the acceleration after MECO, that the second stage did not ignite, and that the subsequent trajectory was ballistic. From the video, there may have a few subsequent ignition attempts, but none were successful.

On a side note, I was very impressed by the 'disk' comprised of nine shock cones in the exhaust plume, immediately below the nozzles. It will be interesting to compare that effect as produced by the 33 engine Starship booster, hopefully next month.

[Jim]

Computer modeling informing rocket design helps a lot, but when you have a rocket like Terran, which is not made of metal panels and could be more vulnerable to dynamic pressure on its exterior, successfully passing Max Q is something of an achievement.

There are structural tests done on the hardware to simulate Max q.

[edkyle99]

One area where these smaller companies may lack testing is the ability to perform vacuum test stand firings for upper stage engines.  Not sure if Relativity had that kind of testing performed.   If not, yesterday was the test.  Hopefully they have enough telemetry to figure out the start up problem.

 - Ed Kyle

[edkyle99]

Wondering what this one weighed at liftoff.  Thrust was 207,000 lbs reportedly,  A T/W of 1.25 would give GLOW = 165,600 lb.  T/W of 1.20 would be GLOW = 172,500 lbs.  1.15 would be 180,000 lbs.
 Etc.  Seemed to rise relatively quickly, but not super fast.

 - Ed Kyle

[kraisee]

They experienced a start-box criteria abort for one or more of the main engines on the previous launch attempt. They ignited and were shut down again before T-0.

I wonder if the cause of the US engine failure on this flight might not be in exactly the same family?

Ross.

[Jeff Lerner]

They experienced a start-box criteria abort for one or more of the main engines on the previous launch attempt. They ignited and were shut down again before T-0.

I wonder if the cause of the US engine failure on this flight might not be in exactly the same family?

Ross.

Was thinking along the same lines…too tight criteria on a first launch attempt…??..slightly different numbers than expected due to actual results experienced in flight ?…we will see but I’m betting it’s something minor and easily correctable..

[Comga]

One area where these smaller companies may lack testing is the ability to perform vacuum test stand firings for upper stage engines.  Not sure if Relativity had that kind of testing performed.   If not, yesterday was the test.  Hopefully they have enough telemetry to figure out the start up problem.

 - Ed Kyle

There’s vacuum AND freefall AND sloshing and other things, post-vibe, aero-thermal heating, induced thermal gradients, electrical transients. They can’t all be simulated.

So you are repeating what Musk said about Falcon 1 which he parroted from the first launch of the Saturn V.  While the first stage can be tested with a dummy payload, if it flies right, it produces the only real-life test of the second stage. 

So we are in agreement:  Yesterday (Wednesday) was the full-up test of the second stage.

It’s a big jump, one that would terrify me, and one for which Relativity tried repeatedly to manage expectations.

[jimvela]

Hopefully the 2nd stage was well instrumented and that telemetry is sufficient to refine and correct for any issues with the design.

It’s great that they got as far as attempting 2nd stage ignition. There’s just no substitute for flight test data- especially when proper facilities to test in a flight-like regime are so expensive.

Will be interesting to see how many more Terran 1 flights they attempt and what else gets added for next flights (fairing, relights, payload separation?)

[edkyle99]

Autogenous tank pressurization may be a challenge for engine starting too.  Not too many upper stages have used that system over the years.  The Titans did, but that was ambient temperature hypergolics. 

 - Ed Kyle 

[edzieba]

They experienced a start-box criteria abort for one or more of the main engines on the previous launch attempt. They ignited and were shut down again before T-0.

I wonder if the cause of the US engine failure on this flight might not be in exactly the same family?

Ross.

Neither of the two launch attempt aborts were due to issues with first-stage engines. The first was propellant conditioning, and the second was a violated criteria in the stage-sep system followed by upper-stage tank pressurisation. The stage-sep criteria issue was the only one where the first stage engines ignited, and they ignited stably and remained lit (i.e. exited the start box successfully) until the abort was commanded.

[mn]

(as already mentioned earlier)

There's a million miles of difference between first stage ignition launch commit criteria and 2nd stage ignition once you are already halfway to orbit.

It seems to me inconceivable that the 2nd stage engine would have any logic that says abort the ignition attempt because something is (or seems) out of any type of bounds.

[FutureSpaceTourist]

https://twitter.com/thetimellis/status/1640444713630326784

A ton of historic firsts last week. Our @relativityspace team proved more in this first launch than most companies (and even countries) ever have in their maiden attempt:

✅ first methane fueled rocket in the West to reach space, well over the 100km Karman Line (only other is China)
✅ first nearly entirely 3D printed rocket to fly and prove 3D printing is viable by passing Max-Q, the max stress on the rocket
✅ first methane orbital-class rocket to successfully complete stage 1 flight, main engine cutoff, and second stage separation in the West (only other is China)
✅ first-ever second stage ignition attempt during the vacuum of flight for a methane fueled orbital rocket in the West, collected first-ever flight data
✅ continuing data reviews, and will bring learnings to our future rocket including Terran R
✅ one really ecstatic launch viewing experience - here, as close as one can get to the launch pad. INTENSE 12 of 10, the reaction makes perfect sense when being there, surreal 🤯

[ulm_atms]

Relativity must have someone on hand just to find "firsts" at this point.  They drive that point so hard and so constantly even when the "firsts" they are talking about really doesn't mean anything.  I mean, everything has it's "firsts" when it's new.

Their constant hammering of "firsts" and "historic" in every PR piece they release does not instill me with confidence of their long term survival.  It reminds me of fluff PR pieces.....no substance.  It's like they are screaming look at me over and over again.  I've never seen anything that does that ending well long term.