Ag_of_08 said:

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OnlyForNow said:

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Bigger than those MOABs we dropped on the bad guys in the desert?

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Allegedly yes, the one that blew on the pad is supposed to be the biggest non nuke explosion .

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The N1 disaster is listed at 8th all time on Wikipedia. The starship explosion with SH on the pad would be worse, without doubt. The nuclear bomb dropped on Hiroshima was the equivalent of 15 kilotons of TNT, and the total for the stack would be around 14 kilotons equivalent (but it would burn longer than a nuke, I think). So it would be bigger than N1, but a bit smaller in total explosive power vs. Fat Man/Little Boy.

Which sort of explains Musk's position on the abort system question I think. No parachute is gonna save a hundred people if that happens. He has stated;

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You know, parachutes don't work too well and [you can't have] some standard abort system, and just how do you abort 100 people it's just not feasible, the key is to make the spaceship itself extremely safe and reliable, and have redundancy in the engines, high safety margins and have [it be] well tested. Much like a commercial airliner. Like they don't give you parachutes."

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Tim at everyday astronaut addressed this in some detail a couple years ago, as well.

In just a couple of posts down in that Reddit, someone echoed what I said earlier. All of the fuel in the full stack is not likely to detonate in the speed necessary to release all that energy at once like a bomb. Also the speed of the shockwave will be limited as well. You even acknowledge it will burn for longer but fail to append the implication that the energy released per unit time will be lower as a result. It is far from certain that all propellants will even ignite. Starship has crashed before and exploded with a fireball and also a vapor cloud of propellants that never ignited. These mishaps are chaotic with high variances in mixing ratios, concentrations, pressures, and temperatures that result in a lot of limited reactions around the mishap.

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I'll give it a shot! All numbers are approximate. And I'm on my third beer.

Full stack propellant capacity is 4,600,000 kg. The Raptor oxidizer/fuel ratio is 3.8/1, thus including 956,800 kg of methane. The energy density of methane is 50.5 MJ/kg, thus containing 48,318,400 MJ of energy. This converts to 48.3184 TJ (terajoules). 1 kt of TNT contains 4.184 TJ of energy.

49.3184 TJ total fuel energy / 4.184 TJ/kt TNT = 11.5 KT TNT equivalent, which is slightly less yield than the bomb dropped on Hiroshima.

Relax. This is a false equivalent. The propellant in Starship/SuperHeavy cannot explode in the same sense that TNT or a nuclear device does. In TNT, the oxidizer is precisely and uniformly mixed with the fuel, so all of it can combust almost instantaneously, limited only by the velocity of the shock wave traveling through the material. In a liquid fueled rocket, the combustion rate is limited by the speed that the fuel and oxidizer can mix after the tanks are ruptured. This results in a very fast and intense fire, not an explosion. You can clearly see this in the videos of "the AMOS-6 explosion" and the in-flight abort test linked below.

https://www.bbc.com/news/world-us-canada-37247077



The energy contained in the Starship full stack methane is about 13.5 times that of the RP-1 in the Falcon 9 full stack. Obviously, if Starship "blows up", it would result in much larger and longer duration conflagrations than those in the videos, but it's certainly not something that cannot be prepared for.

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Part of what some of those assumptions miss though is that the tanks on the starship/super heavy are very pressurized (and alternatively ordered between the two stacked vehicles). It may not technically be an 'explosion' to some, but it would conflate really really quickly, with bits of steel rapidly moving about to help mix it as well.

On the pad you'd also have a huge amount of water below to add to the explosive shockwaves (water vapor is quite powerful of course), and possibly any residual fuel in the nearby (imho too close) tank farms).

If you've ever seen a large natural gas line rupture (as in, 36 inches or more), it is definitely not a 'fire ball' but very much an explosion, imho.

But natural gas is explosive because it mixes with air well enough until it reaches an ignition source at it's optimum mixing to ignite. This releases a lot of energy in an instant and then it is a fireball. The gas is also room temperature when it detonates. The relatively small amount of lag time for cryogenic liquids to heat to vaporization takes more time due to state change and heat transfer than natural gas and it does not do so homogeneously.

What happened on N1 is because when mixed with air, kerosene is as explosive as gunpowder. Methalox not so much.

The greatest potential for a highly explosive event would be small in comparison to the total amount of propellants in each stage. This would likely happen in the methane downcomer where the two propellants are close to one another. Otherwise the two propellant tanks are rather far from each other. This would be a relatively small explosion followed by a rather large and drawn out BLEVE which would likely have enough infrared to melt paint within a half mile. But that is just a guess. I just don't see the likelihood being high that you would have a high yield detonation of a high percentage of the propellants in an instant like some suggest. I think the launch facility would be damaged but not Hiroshima and not close.

In case anyone's sitting near a computer with nothing to do, they're trying to do another S20 static fire at the moment.

I'm still not convinced, respectfully, that if you have the huge quantity of (cryogenic) methane-liquid oxygen, and sonic/sound/water of the 1st stage SH going off at the bottom, if you have a rupture of the methane/lox tanks stacked above the 'explosion' (or conflagration) won't be quite incredible and rapid, vs. for instance a huge pile of coal with an equivalent newtonian energy power slowly burning.

This was just, what, about 1/1000th of the fuel in what was basically just the empty upper stage waiting to be vented and it seemed to go off quickly (it all burned in basically a couple seconds)? No, it's not a nuclear bomb detonation, but it's not a 'slow burn' either.

As I understand it, SN-10's explosion was the result of a methane tank leak from the hard landing that resulted in the initial explosion. It may look dramatic but it did not leave a giant crater.

If this happens with a full stack, the concussive explosion would be somewhere in the same realm. Perhaps larger or more powerful if the leak takes longer to find an ignition source and more methane vapor is present. But the resulting BLEVE would be considerable. But the difference between ignition of 80% of the propellants over 2-5 seconds is drastically less catastrophic than ignition of 80% of the propellants in 500 milliseconds or less.

I recognize that I could be wrong but Elon has been pretty spot on with his risk assessment so far. He thinks this would be a large BLEVE or fireball.

I think there is considerable probability that we will see a mishap of the full stack at some point. I hope that it does not cause too much of a setback with damage to the launch site or surrounding areas.

I want to agree with you, fwiw, and I think you know more about this than I do (as of course does Musk). Still, it's a scary prospect and I'm just not sure. I just have to assume that at a minimum the entire launch tower would have to be rebuilt.

So Rocket Lab (the guys 3D printing their stuff) had an update on their new Neutron rocket this morning.



Note that they are integrating the fairings with the first stage, and literally shooting the second stage out of the first like a bullet from a gun. That's an interesting idea.

A lot of subtle digs at SpaceX there, LOL. It's a fun rivalry, imho.

Yeah, noticed those. But I don't think it's as bitter as the one with BO. Pretty sure I remember Elon tweeting congrats to these guys at one point.

Meet the new and upgraded #Neutron rocket from @RocketLab, featuring 7 Archimedes engines (1 meganewton engines) on the first stage.

A lot has changed since March -- including the propellants the rocket will use and its recovery plans. ⬇️https://t.co/z7Lvr8YBos

— Chris G - NSF (@ChrisG_NSF) December 2, 2021

A bunch of fairly significant goings-on update for starbase/Boca Chica;

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First up, following a successful six-engine Raptor static fire the first in Starbase history on November 12th, all signs pointed to Starship S20 attempting another static fire (its fourth) on December 1st. In the almost three weeks of inactivity between those planned tests, SpaceX likely performed extensive inspections of the pathfinder prototype and its Raptor engines. Technicians also repaired the minor heat shield damage and tile loss that testing incurred and patched a few other 'holes', effectively leaving Ship 20 with the first fully finished heat shield by the end of November.

Earlier this week, one of the few remaining Boca Chica Village residents received a safety notice from SpaceX indicating that a static fire test was scheduled on Wednesday, December 1st followed soon after by a notice to mariners (NOTAM) warning boaters to keep to a safe distance. Two hours into the 10am to 6pm CST test window, Starship S20 was already venting and starting to get frosty, confirming that propellant loading had begun. A little over an hour later, it was clear that SpaceX had aborted the first static fire attempt of the day. For the next three hours, Ship 20 exhibited some unusual behavior including new vents, an apparent header tank pressurization or fill test, and still more odd venting in new places.

….

Altogether, the weird half-complete test stand and bizarre fusion of ship and booster parts make B2.1's purpose and initial testing a complete mystery. It's unclear what value it provides that makes it more of a priority than, say, finally starting to test the first flightworthy Super Heavy booster (B4). Ultimately, the most interesting thing about B2.1's test debut is the fact that it appears to mark the first use of Starbase's brand new orbital tank farm, which is approaching completion.

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Stumbled across this repost, pretty cool.

NASA exposes first ever footage of a blue sunset on #Mars pic.twitter.com/EE8abNnnS6

— Space Porn (@redditSpacePorn) December 3, 2021

and...

Liftoff! pic.twitter.com/7ZlakB8pSk

— SpaceX (@SpaceX) December 2, 2021

and...

Falcon 9’s first stage has landed on the A Shortfall of Gravitas droneship pic.twitter.com/mvnvL25hrf

— SpaceX (@SpaceX) December 2, 2021

This was another milestone;

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Almost exactly mirroring Blacksky's first August 2020 Starlink rideshare mission, Falcon 9 first deployed the company's two ~60 kg (~130 lb) Earth observation satellites around T+1:03. The second stage then gradually spun itself up end over end before releasing all 48 Starlink V1.5 satellites at once ~90 minutes after liftoff, marking the end of Falcon 9's 101st consecutively successful orbital launch and SpaceX's 27th launch of the year new records for western spaceflight and the company, respectively.

As previously discussed on Teslarati, with Starlink 4-3, SpaceX's Falcon 9 workhorse has become the first western rocket in history to surpass 100 consecutive launch successes, beating out McDonnell Douglas' (and, later, ULA's) Delta II rocket.

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"As pointed out by a Teslarati reader, Starlink 4-3 could also see Falcon 9 become the first American rocket in history to successfully complete more than 100 orbital launches in a row, narrowly beating out McDonnell Douglas' retired Delta II rocket for the title. Earlier this year, many outlets already reported that SpaceX's May 26th Starlink-28 launch was its 100th consecutive launch. While true in a very literal sense, it ignores SpaceX's infamous Amos-6 Falcon 9 failure, which occurred well before liftoff but still destroyed both the rocket and payload.

Only Russia's R-7 (Soyuz) rockets the most-launched rocket family in history have successfully launched more times in a row. Since 1966, Soyuz rockets have launched more than 1900 times and the family has repeatedly completed 100 consecutively successful launches over its decades of operation. Eleven years after its debut, Falcon 9 currently stands at 127 fully successful launches a lifetime away from matching Soyuz but still well on its way to a thoroughly impressive second place."

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SpaceX has also beaten its 2020 record of 26 launches completed in one year and still has at least three or four more launches planned in 2021 potentially pushing the company past the 30-launch mark before the end of the year. Up next, SpaceX is scheduled to launch NASA's Imaging X-ray Polarimetry Explorer (IXPE) no earlier than (NET) 1am EST (06:00 UTC), December 9th; Turkey's Turksat 5B communications satellite NET 10:58 pm EST (3:58 UTC), December 18th; Cargo Dragon 2's CRS-24 space station resupply mission NET 5:06 am EST (10:06 UTC), December 21st; and (potentially) Starlink 2-2 or 2-3 NET late December.

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Elon just tweeted that they have begun construction on a Starship launch pad at 39A in Cape Canaveral.

will25u said:

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NASA exposes first ever footage of a blue sunset on #Mars pic.twitter.com/EE8abNnnS6

— Space Porn (@redditSpacePorn) December 3, 2021

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So superman is screwed on Mars?

SpaceX continues to push. Love it.

That's a big hairy deal. A lot of infrastructure needed (not just tower but methelox) plus probably a lot of delays to 2022 launches to build it.

I guess it will be in the 39A 'circle' but they probably will be building it up next to the structure for the F9, not in the middle/to replace it. First step was taking out some of the original Starship diverters concrete that I suppose the design has changed over the past few years.

Using imagery from last year we can see the changes. The ramp pieces of the flame diverter that were led on the ground are also now gone.

© AIRBUS DS 2021/2020 pic.twitter.com/cQKEmW6y3g

— Harry Stranger (@Harry__Stranger) December 3, 2021

I guess that means we'll see another tower crane/chopstick situation. Should be fascinating to watch.

The question is if they will rent a big crane for construction again or build their own. The next question is if they will simultaneously start a tower construction on the drilling rigs they have reduced basically down to flat decks as of now. It just depends how seriously committed they are to bi-weekly launches in a year.

Where will they launch the Falcon 9s from? And what pad will service the crew dragons?

They'll continue to launch F9 and Crew from 39A as well.

This will look so awesome!

— Elon Musk (@elonmusk) December 3, 2021

Blue Origin to…miss yet another timeline. This time for BE4 engines to be delivered this year.

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We're in the end game now," Tory Bruno said Dec. 3 on CNBC
WASHINGTON Blue Origin is performing "final testing" of the BE-4 engines that will boost United Launch Alliance's Vulcan Centaur rocket, ULA's CEO Tory Bruno said Dec. 3.
"We're in the end game now," Bruno told CNBC in an interview.
Blue Origin's continued delays in BE-4 engine development and production set off an industry guessing game on when ULA would finally receive the two engines it needs for the inaugural flight of its Vulcan rocket.
Bruno had previously said he expected the engines in late 2021 but on Friday he confirmed the BE-4s will not arrive until early 2022.
"I was hoping to get those engines for Christmas. I had giant stockings at home waiting for them," Bruno quipped in the CNBC interview.
"I'll say it's taking them a little longer to fabricate my production engines. They're in the factory now being built at Blue Origin," said Bruno.
"The COVID epidemic has affected them and their supply chain and it's just taking a little bit longer, but they're doing very, very well," he added. "There's been no problems with them and in fact, we're doing the final testing, or what we call certification testing. And that is just going really, really well."
Bruno has said in recent years that the engine delays have been frustrating but on Friday he put a positive spin on it. "This is the hardest and most exciting part of any rocket development program. It is being paced by those brand new engines, their new technology and new fuel."
The first two engines will be used for Vulcan's first launch some time in 2022, said Bruno. He said Vulcan will fly two missions before the year ends.

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Not the worst update overall, still, as with all things BO, I'll believe it when I see their hardware on a pad launching to orbit.

Can't wait till the total eclipse comes through Texas in little over two years. I drove to Missouri for the last one. It's freaking amazing. Make sure you are in the path April of 2024!!

Interesting study done on the 2019 eclipse that came across Chile. They used 24 GPS stations as a lens to see the ionospheric distortion caused by the eclipse. I may have to see if I can organize some other surveyors to have their receivers running at the time to bolster the CORS data.

https://pubmed.ncbi.nlm.nih.gov/33168833/

YellowPot_97 said:

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Can't wait till the total eclipse comes through Texas in little over two years. I drove to Missouri for the last one. It's freaking amazing. Make sure you are in the path April of 2024!!

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I thought about driving to Missouri but decided against it when I learned there would be another visible from Dallas seven years later. I'm really hoping for clear skies.

YellowPot_97 said:

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Can't wait till the total eclipse comes through Texas in little over two years. I drove to Missouri for the last one. It's freaking amazing. Make sure you are in the path April of 2024!!

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I went to Wyoming last time to see the eclipse, which was freaking amazing. I waited 40 years for that one.
My 360 video


Very glad I only have to wait until 2024 this time.

Friend of mine is on an Antarctic cruise and saw it.

A little video of yesterday's total solar eclipse going into totality. Taken aboard the National Geographic Endurance. @LindbladExp @NatGeo #SolarEclipse pic.twitter.com/kh1ERppHLn

— Caroline Lupini (@carolinelupini) December 5, 2021

B2.1 on the move!

@considercosmos

PJYoung said:

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B2.1 on the move!

@considercosmos

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Always amazed at the pictures of moving these things... The vehicles for scale is pretty mindboggling.

I really need to make it down there...

Gratz to the new AsCans!