SpaceX's Falcon Heavy Center Booster Lacked Ignition Fluid To Light Engines and Land On Platform (latimes.com)

An anonymous reader quotes a report from Los Angeles Times: The center core booster of SpaceX's Falcon Heavy didn't land on a floating sea platform as intended during last week's first test flight because it ran out of ignition fluid, company Chief Executive Elon Musk said Monday. Musk took to Twitter on Monday morning to give a few more updates on the Falcon Heavy's first flight. After liftoff, the rocket's two side boosters touched down simultaneously on land, eliciting cheers and applause from the crowd of SpaceX employees gathered in the company's Hawthorne headquarters, as seen on the launch livestream. Those two boosters, which were used in previous launches of SpaceX's workhorse Falcon 9 rocket, will not be reused again, Musk said in a post-launch news conference last week. But the center core booster ended up hitting the Atlantic Ocean at 300 mph and about 328 feet from the floating platform where it was supposed to land. Musk said Monday that there wasn't enough ignition fluid to light the outer two engines of the booster "after several three engine relights."

Comments

Missed it by *that* much.

[ColdWetDog]

Sorry guys, this isn't horseshoes or hand grenades.

It's rocket science.

Re:Missed it by *that* much.

[Anonymous Coward]

Not sure the point you are trying to make here... It was a test flight. The first time they have had to slow down a booster from this sort of burn, with the longest set of three engine burns so far.

Turns out the current build doesn't have enough igniter fluid. But they captured that data, and can now correct for it.

It is exactly the same thing that happened with the early test landings of the Falcon 9 boosters, where they weren't sure how much hydraulic fluid they would need. Now they know, and now they land the Falcon 9 boosters with an incredible success rate.

They can't just calculate exactly how much they need of these things, because the atmosphere adds a highly dynamic variable. They can take a very educated guess, but as the landing is automated and corrects for a wide variety of conditions, this is one of those "we have to do it to see... and we might not even get it right the second... or third... or fourth time."

Re:Missed it by *that* much.

[beelsebob]

I agree with you for the most part. My one surprise in all of this is that they don't over-design the first vehicle. I'd have expected them to give themselves 15% more than they calculated they needed, and then observe "oh hey, we only needed 2% more than we thought" when it landed.

On the other hand, I guess maybe they did do that, and discovered that they needed 17% more than they thought.

Re: Missed it by *that* much.

[c6gunner]

You would think with something like ignition fluid they would just go 100% more right off the bat, and see how much they actually use. It has to be a teeny tiny fraction of the total rocket's weight. Yeah, it would mean having to build larger storage tanks for it, too, but if it saves your multimillion dollar rocket from performing the worlds largest cannonball ....

Re:Missed it by *that* much.

[tquasar]

Thanks, Agent 86.

Re: Missed it by *that* much.

[TWX]

We don't really know how much they actually included. For all we know they already had increased the quantity to what they thought was a safe margin.

The balancing act is pretty insane, any increase in rocket mass means a decrease in payload mass. They literally have to build a rocket that's just equipped to do what it needs to do in order to maximize payload. After all, a rocket is cool and all but it's the payload that really matters.

If they do decide to add more fluid then they'll probably see if they can cut mass anywhere else. It may not take much, but finding 50-100lb is going to be a challenge.

Re: Missed it by *that* much.

[fredgiblet]

Sure, but this is a TEST flight, so I would argue that it's more important to start with a smaller payload. That way you can work down from safe to probably safe and have less risk of losing the test vehicles.

Re: Missed it by *that* much.

[c6gunner]

For a test launch with a minimal payload they had plenty of capacity to spare. That rocket was capable of launching 37,000 pounds out past Mars. Granted that's in the fully expendable mode; I'm not sure what the capacity is when recovering all 3 stages but extrapolating from the figures they provided for LEO and GTO it should still easily exceed 4,000 lbs when launching towards Mars. Meanwhile the roadster clocks in at 2,800 with the batteries in; much less after they removed those.

But yeah, it's definitely complicated. I don't know how exactly they store and dispense the ignition fluid so it's kinda useless to speculate about the practicality of including a lot more of it.

Re: Missed it by *that* much.

[cjameshuff]

It's a minuscule amount of the booster's mass, and mass is less important on the first stage anyway, but it's also a volatile fluid that spontaneously ignites on contact with air. You have more reasons than mass to want to minimize the quantities you're working with, especially when working with experimental hardware where things may go wrong.

Re: Missed it by *that* much.

[Anonymous Coward]

Not really. They had no intention of reusing that core. Its loss is a nuisance because it damaged the drone ship, but its economic value post mission was zero.

Re: Missed it by *that* much.

[Kjella]

Sure, but this is a TEST flight, so I would argue that it's more important to start with a smaller payload. That way you can work down from safe to probably safe and have less risk of losing the test vehicles.

Well, it's less risk to the test vehicle but the more your final configuration deviates from the current configuration the higher the risk of some unexpected side effects. When you can count the number of tests on one hand with fingers to spare it's better to fail on the first test and say that's what tests are for than fail on the second test and raise concerns that it has hidden flaws that might kill missions at random. Despite all that Elon Musk said to manage expectations they did not send a $100 million dollar rocket out there to blow up an equally expensive pad on a 50-50 or 2/3rds chance. They've extensively tested every component and subsystem they could find, simulated it a million times with computers and it would have passed with flying colors.

This is the final integration test, not the first test. The rest is that X factor, what haven't we taken into consideration. Are our assumptions, models and formulas flawed in some way. He can't really lose talking it down, if it blows up on the pad well space is hard. If it works, he's pulled off some amazing feat. So I'd want something very close to the production model flying, as long as the odds remain good you'll get your test data. And in that respect this was an entirely insignificant failure, they got telemetry on everything right up to the final impact. Making this part of the mission fail-safe wouldn't really have any big benefit. Just downsides in redesign, if this was what they thought was the right amount.

Re: Missed it by *that* much.

[fredgiblet]

I don't know exactly how much that unit costs, but I'm pretty that saving it would be a very big benefit.

Re: Missed it by *that* much.

[jimtheowl]

The teeny tiny fraction adds up, because you need more fuel to lift that, then you need more fuel to lift the extra fuel.. and so on.

Remember that this was a test flight. I would have been worried if everything had worked out perfectly.

Re: Missed it by *that* much.

[Anonymous Coward]

The important thing, given this was a flight test is they seem to have enough data to figure out the problem, and to do so fairly quickly.

Of course it could have been something they hadn't instrumented, though I suspect there aren't many things without some kind of logging facility within the limits of available bandwidth..

Re: Missed it by *that* much.

[K. S. Kyosuke]

You would think with something like ignition fluid they would just go 100% more right off the bat, and see how much they actually use.

There's also the issue that the ignition compounds are 1) toxic and pyrophoric crap and 2) gunk up the engines, so you don't really want to carry more than what you need because either people in hazmat equipment would need to deal with safely removing it after landing, or alternatively, you'd have to use it all up during the last ignition and then deal with the gunk.

Re: Missed it by *that* much.

[K. S. Kyosuke]

The test launch used two older boosters running at 92% of thrust, though. And for high energy missions, the performance delta from this difference is going to be the greatest.

Re: Missed it by *that* much.

[Anonymous Coward]

Despite all that Elon Musk said to manage expectations they did not send a $100 million dollar rocket out there to blow up an equally expensive pad on a 50-50 or 2/3rds chance. They've extensively tested every component and subsystem they could find, simulated it a million times with computers and it would have passed with flying colors.

That's false logic. Of course they tested extensively, but that doesn't mean that the actual chance of success was greater than 50%. They probably did their best with the Falcon 1 as well, but they still blew up 3 of them at a total cost of $100 million before they were successful.

Re: Missed it by *that* much.

[Anonymous Coward]

I don't think anything was going to be reused. Something about not being block 5, which I gather is the newest version of the hardware.

Re: Missed it by *that* much.

[fox171171]

The teeny tiny fraction adds up, because you need more fuel to lift that, then you need more fuel to lift the extra fuel.. and so on.

Exactly. Most of the fuel on a rocket is there to lift the weight of the fuel.

Re: Missed it by *that* much.

[Anonymous Coward]

None of them were ever intended to fly again... They were cobbled together from flight proven boosters and were a mix of block 3 an 4 tech.

Re: Missed it by *that* much.

[drsquare]

Rockets are very weight sensitive, you don't have the luxury of over-engineering them.

Re:Missed it by *that* much.

[Anonymous Coward]

Not sure the point you are trying to make here

It's called a JOKE. Woosh...

Re:Missed it by *that* much.

[mcswell]

You're welcome, 99.

Re:Missed it by *that* much.

[Anonymous Coward]

Hear it like I read it.

Re:Missed it by *that* much.

[sysrammer]

"Woof" - 13

If it is true, oh well ;)

[oldgraybeard]

They are trying to perform a complex process and there will be failures and successes, In the real work stuff happens!

Just my 2 cents ;)

Re:If it is true, oh well ;)

[oldgraybeard]

;) lol
In the real work stuff happens!
yes I did mean
In the real world stuff happens!

;) me bad

Re: If it is true, oh well ;)

[Anonymous Coward]

;)
Ya. ;)

It does ;) ;) ;) oh boy ;) ;) ;)

True ;) hmmm ;)
That a fact

Re: If it is true, oh well ;)

[Anonymous Coward]

What is this computer code stuff I don't even

"The fix, he said, was pretty obvious..."

[Anonymous Coward]

Crumple up old newspaper under the engines...

Re:"The fix, he said, was pretty obvious..."

[Anonymous Coward]

A spare gas can in the trunk always works for me.

Captcha: fire man

Fluid levels...

[Anonymous Coward]

I forgot to top off the blinker fluid in my 1973 Pontiac Cadillac and my turn signals failed to blink.

Re:Fluid levels...

[Anonymous Coward]

My muffler bearings went bad. I noticed when I was putting winter air in my tires.

Prompts a question

[arth1]

Those two boosters, which were used in previous launches of SpaceX's workhorse Falcon 9 rocket, will not be reused again, Musk said in a post-launch news conference last week.

Then why spend fuel and other resources on landing them?

Re:Prompts a question

[Snotnose]

Probably as a test. Sure, they landed on their feet. But I'm there there is a wealth of telemetry telling them what went right, what went wrong, and what almost went wrong.

Re:Prompts a question

[DamnRogue]

Practice.

Re:Prompts a question

[beelsebob]

Because this was a test flight, and they needed to verify that separating and landing the side boosters worked. Now they need to verify that in doing all of that, no damage got caused to them, so very likely they're going to completely take them apart and look at every component in detail.

Re:Prompts a question

[Anonymous Coward]

Practice. Data. Expertise.

Re:Prompts a question

[itamihn]

That's a very insightful question. I guess they did it to keep practising the landing, or to do the first double landing and get the nice video that they got, or maybe so that they can disassemble the rockets and reuse or recycle some materials.

Re:Prompts a question

[spire3661]

Because you simply cant buy PR like this. https://upload.wikimedia.org/w... Absolutely spectacular.

Re:Prompts a question

[Anonymous Coward]

Like the titanium grid fins.

https://www.youtube.com/watch?v=sytrrdOPYzA&t=30m05s

Re:Prompts a question

[haruchai]

Those two boosters, which were used in previous launches of SpaceX's workhorse Falcon 9 rocket, will not be reused again, Musk said in a post-launch news conference last week.

Then why spend fuel and other resources on landing them?

The plan is to only use only Block 5 modules from here onwards but this maiden launch gave them a chance to test recovery using expendable boosters.
Even if reuse is not being considered, I'm sure there's plenty to recycle.

Re:Prompts a question

[fahrbot-bot]

Those two boosters, which were used in previous launches of SpaceX's workhorse Falcon 9 rocket, will not be reused again, Musk said in a post-launch news conference last week.

Then why spend fuel and other resources on landing them?

It's possible some of the parts can be refurbished and reused, even if the entire booster won't be. Also, having them all in one piece allows everything to be studied for wear and possible failure points and help refine future boosters.

Re:Prompts a question

[istartedi]

As a highly rated reply said, "practice". I'd like to add that it's also the only nominal way to land them. The alternative is to make a mess on the LZ, or chuck them someplace where they'd be pollution.

Re:Prompts a question

[Michael Woodhams]

To save people video watching:
In the post-flight press conference, Musk said that the titanium grid fins are hard to manufacture and expensive and they currently don't have many, so he was very pleased to get these ones back. Also, the titanium grid fins are larger, and the side boosters need the bigger fins because the nose cone (rather than blunt end) reduces the effectiveness of the fins.

Re:Prompts a question

[sirsnork]

Musk is on record as saying that out of everything that could have been recovered, those two side boosters are the things he most wanted back. They have the upgraded titanium grid fins on them which can and will be re-used, and are seemingly a) very hard to make and b) expensive as hell.

As a side note, putting a nose cone on an F9 core drops the grid fins performance by 30%, so those grid fins may actually be the only 2 in existence since they had to make them larger to account for that

Re:Prompts a question

[BenFranske]

Then why spend fuel and other resources on landing them?

I believe I saw one quote from Elon somewhere that even thought they won't be re-used in entirety there will be some re-use of expensive (in time and money) parts from them. In particular I think he mentioned re-use of the grid fins.

Re:Prompts a question

[dfsmith]

According to the post-launch press conference, they landed them because they wanted the grid fins back. Apparently they're rather expensive machined titanium, and were specially made for the "heavy" configuration.

Re:Prompts a question

[arth1]

As a highly rated reply said, "practice". I'd like to add that it's also the only nominal way to land them. The alternative is to make a mess on the LZ, or chuck them someplace where they'd be pollution.

Quite a few modules that have come down from space with parachutes.

Re: Prompts a question

[Anonymous Coward]

Because it proves their comitment to getting it right. Plus they can now be cheaply recycled for other uses. Once they get it to the point where they can sucussfully land every part every time. Then we may see one of musks other ideas become reality.

Re:Prompts a question

[Mandrel]

Even in science and technology, to maximize funding, sales, and valuation, you have to be shameless promoters. With the car-in-space, cheering crowds, and super-enthusiastic hosts, SpaceX's video stream of this launch had more than a touch of P. T. Barnum. I felt for the older engineering director, behind whose smiling "total success" pronouncement was probably a guy thinking "what the hell happened to my core?"

Re:Prompts a question

[istartedi]

Of course; but this one's not designed to do that. If you're committed to the Falcon style of recovery, the parachute system is dead mass. In space flight, mass is money so you sort of have to commit to one recovery system or another.

Re:Prompts a question

[Anonymous Coward]

Seems like a passive recovery system would just be easier. Surely some parachutes would be lighter than the fuel needed to land the rocket. Sure you have to haul them back from downrange but is that really harder?

Re: Prompts a question

[nitehawk214]

They tried that... It didn't work. The parachutes have no control and the thing spun itself apart.

Also you would need parachutes that can operate at supersonic speeds on an 8 story grain silo.

Re:Prompts a question

[psergiu]

Elon Musk said that the two side boosters were using the newly developed titanium guidance fins - and he's happy those two landed fine as those things were expensive and will be reused for other Falcon9 boosters. The center one used the old-style fins (you can see in the pre-launch photos, the fins look different).

Re:Prompts a question

[Anonymous Coward]

The problem is that people always imagine the Space Shuttle Boosters when they think of "recovery, reuse"... but these were Solid Rockets, when empty not much more than a steel shell. They could dump these in salt water, and still refurbish them for reuse (even though it was not cost effective).. you can't do that with a liquid fueled rocket. They are not built to withstand the stresses of being dipped into water, and certainly not for all the corrosive effects from salt water.

You have to land these on legs, on solid ground (or something like that that is NOT water) - and doing that via chutes might be possible, but then you don't have any authority on final descent and where it lands - and if you have to land on a 50x50m platform on the ocean, that is VERY bad.

Re:Prompts a question

[K. S. Kyosuke]

In addition, the nose-coned boosters hadn't been flown before this test flight so their predicted real-life reentry aerodynamics had to be validated as well.

Re:Prompts a question

[K. S. Kyosuke]

What size of parachutes do you need to softly touch down a 25000 kg boooster at ~1 m/s?

Re:Prompts a question

[Anonymous Coward]

To appreciate the complexity of parachute deployment for space craft re-entry watch this video:

https://www.youtube.com/watch?v=fAMqb77Dmzk

Re:Prompts a question

[SharpFang]

Nitpicking: they had been flown, but in a blunt-nosed configuration.

Re:Prompts a question

[Anonymous Coward]

Because even if they don't reuse the boosters they can recover most of the materials. Something they can't do with boosters that splash down in salt water.

Re:Prompts a question

[SharpFang]

Pretty big, but probably smaller than what the fuel takes.

The problem though isn't just touching at ~1m/s, it's touching within 89 meters of the landing pad radius. Parachute leaves the rocket at mercy of random winds. Soyuz is considered landing "on the spot" when it lands within 1.5km of the planned point.

Re:Prompts a question

[Anonymous Coward]

"then why spend fuel and other resources on landing them?"

Flight data. Basically they had two used first stages, they made some modifications to them to fit them into the basic Falcon Heavy form factor and likely strapped them with untold numbers of sensors. Now that they have the data from that flight they can tweak the final designs of the boosters (and to a lesser degree the core stage) for the final production model. They also have the landed boosters for visual inspections (cracked welds, thermal damage, structural stress, etc). One of the big limiting factors in spaceflight (in addition to lack of reusability) has always been the guesswork involved with trying to assess flight performance due to a lack of the actual hardware for assessment/testing.

Re:Prompts a question

[Anonymous Coward]

Musk said that the titanium grid fins are hard to manufacture and expensive

Musk also said his cock is so big it's almost 3 inches erect.
Titanium is hardly expensive or difficult to work with.
You can buy $300 wristwatch with titanium case.

Re:Prompts a question

[K. S. Kyosuke]

Yep, I meant the their state after the modifications.

Re:Prompts a question

[SamTombs]

Or you can buy the same watch in stainless steel for $25.

Re:Prompts a question

[SamTombs]

Thank you for prompting instead of begging.

Re:Prompts a question

[torkus]

Because the fuel cost to do so is minimal and, even excluding telemetry data and simply practicing the complexity of landing three boosters simultaneously, the scrap/parts value of the boosters is rather substantial.

Re:Prompts a question

[Anonymous Coward]

Or you can buy the same watch in stainless steel for $25.

Citizen Eco-Drive Titanium Perpetual Chrono for $350 (sale price)

same except stainless steel for $300

Grab your friend Dashawn's $25 offer if it's still available.

Re:Prompts a question

[sysrammer]

So sweet it almost looked fake.

Re:Prompts a question

[sysrammer]

Bet it'll be a while before you ask a question on /. again :)

BTW...he wanted the fins back.

An easy fix

[Midnight Thunder]

Given this was a first launch of something so complex it is amazing more didn't go wrong. Sure simulators have vastly reduced the risk (probably not a Kerbal Space Enterprise Edition ;) ), but simulators are still not a good replacement for real world testing.

If it was only a lack of ignition fluid, then that seems like an easy fix, compared to all the other variables they have to deal with.

Fake News

[Anonymous Coward]

Elon hasn't tweeted since Sunday

"About 328 feet"

[Anonymous Coward]

FFS, America, USE METRIC !

Re:"About 328 feet"

[pezpunk]

but a meter is a lot more than a foot -- if they had used metric, it would have landed even farther away.

Re:"About 328 feet"

[dohzer]

They did. Well, at least the engineers did.

There are two types of countries: those that use the metric system, and those that lose wars to Vietnamese farmers.

Re: "About 328 feet"

[Anonymous Coward]

Which category do you put France in?

Re:"About 328 feet"

[kenai_alpenglow]

I didn't know the Chinese didn't use metric.

Re: "About 328 feet"

[Anonymous Coward]

Make love to Vietnamese farmers daughters?

Re:"About 328 feet"

[Chuq]

especially since 328 feet = 100 metres, which is the unit in which the measurement was originally given.

Re:"About 328 feet"

[Anonymous Coward]

Or, ironically, the French.

Re: "About 328 feet"

[Anonymous Coward]

Well played!

Re:"About 328 feet"

[Thelasko]

Or, ironically, the French.

Based on the score, no one gets this joke. However, it is hilarious

See, France has been a major contributor to the development of the metric system, and is the keeper of the international prototype kilogram.

Vietnam was a French colony, known as French Indochina, until a bunch of Viatnamese farmers kicked them out in the First Indochina War.

Wow

[Anonymous Coward]

Was the fuel tank not big enough of not full enough for the mission? Pretty fundamental failure there.

Ignition fluid is TEA-TEB

[JoshuaZ]

The ignition fluid in question is TEA-TEB https://en.wikipedia.org/wiki/Triethylborane#Rocket, a mixture of triethylborane and triethylaluminium. This is a common ignition fluid for rockets which burn RP-1 (rocket grade kerosene), since RP-1 is hard to ignite. The two are mixed because one of the two has really dependable ignition while the other one burns more cleanly. This sort of ignition system has been in use since the 1960s, but SpaceX is the first to use the TEA-TEB ignition system to ignite a rocket engine while the rocket engine is moving quickly *downwards* into the atmosphere. Experiments will sometimes work, and sometimes won't. They are obviously figuring out just how much TEA-TEB they need.

Re:Ignition fluid is TEA-TEB

[psmoot]

Experiments will sometimes work, and sometimes won't. They are obviously figuring out just how much TEA-TEB they need.

That's what seems odd. They've re-lit Falcon engines dozens of times by now. I'm surprised the amount of igniter varies by much so I expected the knew how much they needed. Does the amount of igniter vary much based on, say, the speed and altitude of the booster? Do those parameters vary by that much between normal Falcon 9 and the Falcon Heavy flights?

I'm guessing it must vary by more than I expect. These guys are rocket scientists after all. If it was that simple and predictable, we wouldn't have a new clip for the blooper reel.

Re:Ignition fluid is TEA-TEB

[JoshuaZ]

Center core is heavier than a regular Falcon 9 first stage, so it has a higher terminal velocity. So it may take more TEA-TEB to reliably ignite the engines when they are coming down that way.

Re:Ignition fluid is TEA-TEB

[jimtheowl]

It does vary as much on the speed and altitude as how many times they had to re-ignite it during descent.

Re:Ignition fluid is TEA-TEB

[FormOfActionBanana]

It was probably a leak.

Re: Ignition fluid is TEA-TEB

[psmoot]

I assumed it was the normal three burns: boost back (if needed), reentry, and landing. As another poster mentioned, there might also have been a leak.

Re:Ignition fluid is TEA-TEB

[Anonymous Coward]

Does Assange have anything to do with it?

Re:Ignition fluid is TEA-TEB

[Moskit]

Apparently during ignition TEA-TEB is kept running until engine parameters are within the "I am working correctly" range. Consumption changes depending on various conditions such as engine temperature or air speed, which were different for the center core.
SpaceX has a lot of experience restarting those engines in Falcon 9 conditions, but this is still rocket science - theory is not always good enough.

Remember how a Falcon rocket ran out of hydraulic fluid for steering during sea landing? They had not enough fluid (it is open system) as well.

BTW - information about running out of TEA/TEB was provided by Elon Musk already right after the launch, during the first press conference. This is old news.

Re:Ignition fluid is TEA-TEB

[yes-but-no]

higher momentum; terminal velocity is independent of mass (according to physics).

Re:Ignition fluid is TEA-TEB

[Anonymous Coward]

And if larger then the central booster may have lower terminal velocity due to extra wind resistance.

Re:Ignition fluid is TEA-TEB

[the_other_chewey]

higher momentum; terminal velocity is independent of mass (according to physics).

In an atmosphere? It absolutely is not.

In an atmosphere, the heavier a given shape is,
the faster its terminal velocity is.

It's pretty obvious: A one meter steel ball, a one meter
styrofoam ball, and a one meter helium balloon all fall at the
same rate in vacuum.

Add Earth's atmosphere, and they don't even all fall in the same direction.

Re:Ignition fluid is TEA-TEB

[psmoot]

Apparently during ignition TEA-TEB is kept running until engine parameters are within the "I am working correctly" range. Consumption changes depending on various conditions such as engine temperature or air speed, which were different for the center core.

Ah. I see. That makes a ton of sense. Thanks. This is truly news for nerds, stuff that is totally irrelevant to our daily lives.

Re:Ignition fluid is TEA-TEB

[yes-but-no]

styrofoam/helium are pathological eg. Of course in atmosphere -- terminal velocity is a property of fluids. So you need atmosphere. The difference between say 1 kg iron ball and 25000 kg iron ball is zero wrt terminal velocity.

Re:Ignition fluid is TEA-TEB

[drew_kime]

The difference between say 1 kg iron ball and 25000 kg iron ball is zero wrt terminal velocity.

Is that true? I remember enough college physics to believe it's one of those counter-intuitive things, but don't feel like tracking down the right formulas to confirm.

Re:Ignition fluid is TEA-TEB

[meekers]

I don't see why a 1 kg iron ball and a 25000 kg iron ball would have the same terminal velocity in the atmosphere. Mass would scale with third power of the radius, while surface area would scale with the second power of the radius.

Re:Ignition fluid is TEA-TEB

[Lothsahn]

It's unclear to me if the 1kg and 25000kg ball have the same terminal velocity, but the side cores and center core aren't the same shape. The center core is taller...

Assuming both objects are falling on their face and not flipping (the way that the Falcon 9 travels), a penny will fall slower in atmosphere than a long cylinder with the same density and area, even if the orientation of travel of both is in the direction of the surface of the penny. This is because the air resistance of the penny per unit of mass is much higher than the long cylinder. The same aerodynamic effect can be seen on road trains, which accounts for their improved fuel efficiency.

The center core is also likely denser than the side cores. We know the center core is reinforced to handle the additional structural loads. This would further increase the terminal velocity.

Re:Ignition fluid is TEA-TEB

[yes-but-no]

https://en.wikipedia.org/wiki/...
Under Terminal velocity in the presence of buoyancy force for spherical objects; v_t = sqrt(A/B); A= 4gd/3C_d ...etc which is given in link; no reference to mass. Yeah, it may be counter intuitive just like how until Galileo people believed heavier objects fall faster.

Re:Ignition fluid is TEA-TEB

[yes-but-no]

From the formula, there is d - diameter dependence. So it does depend on mass/size. So my initial claim of mass independence is incorrect. I guess I thought the drag force of heavier objects will compensate enough to counteract the heavier mass. [seems the drag is dependent on d^2 but weight on d^3]

Re:Ignition fluid is TEA-TEB

[Impy the Impiuos Imp]

It is mass divided by cross section of barn door plowing through the air, so no, not really. Mass is one of two variables in terminal velocity.

Re:Ignition fluid is TEA-TEB

[Anonymous Coward]

The harder you push an object through a fluid the faster it goes - yes? For and object moving through the air, the force pushing it is gravity. An object with more mass will be pushed (pulled) through the atmosphere with more force (weight). The harder you push an object through a fluid the faster it goes.

I'm honestly not sure if you're trolling. In case you are not, look at the Wikipedia page. https://en.wikipedia.org/wiki/Terminal_velocity
Force of gravity and force of drag. Mass appears in the equation, inertial does not.

Terminal velocity has nothing to do with the initial conditions of the object. If it is shot into the atmosphere, or dropped from a rest. It has to do with the speed it gravitates to.

Re:Ignition fluid is TEA-TEB

[the_other_chewey]

styrofoam/helium are pathological eg.

Just extreme ones to make it obvious, there's nothing that makes those
different in kind from the steel ball with respect to the physics involved.

Of course in atmosphere -- terminal velocity is a property of fluids. So you need atmosphere. The difference between say 1 kg iron ball and 25000 kg iron ball is zero wrt terminal velocity.

Well, as you have written below: That's not true.

Thank you for correcting yourself by the way, that speaks well of you.

Best possible failure

[vix86]

Of the possible failures that could have occurred, this seems like the best one. This was the newest part on the whole 'kit' so it wouldn't surprise me if it was an issue in calculations or some minor mechanical issue that resulted in this. In the end this was still an 80% success and were this a commercial launch, the buyer wouldn't have been overly disappointed since the payload made it into orbit. I have no doubt the next launch will be a complete success with all 3 rockets landing without problem. A big thing I personally took away from this is that SpaceX's iterative development on their launch system (vs scrap the old and build something new) has worked and they'll carry that forward with the R&D for the BFR/BFS.

Re:Best possible failure

[aussie_a]

The payload went into the wrong orbit. Don't forget that.

Re:Best possible failure

[Goetterdaemmerung]

Of the possible failures that could have occurred, this seems like the best one. This was the newest part on the whole 'kit' so it wouldn't surprise me if it was an issue in calculations or some minor mechanical issue that resulted in this. In the end this was still an 80% success and were this a commercial launch, the buyer wouldn't have been overly disappointed since the payload made it into orbit. I have no doubt the next launch will be a complete success with all 3 rockets landing without problem

Don't skimp on the metrics! The mission was 100% success given it launched successfully and put the payload into high orbit. All buyers would be perfectly satisfied with the result. The landings of 2/3 boosters is extra, and the reignition of the second stage to achieve Mars trajectory was extra - although the angle was slightly off. I'd grant these an additional 50% bonus so 150% successful mission far beyond anyone's expectations. Even Musk said he'd be happy if it blew up far enough from the launch pad to not cause damage.

Re:Best possible failure

[Anonymous Coward]

[Citation Needed]

Re:Best possible failure

[cjameshuff]

The target orbit was one that went at least to Mars orbit. There were no requirements that it only go to Mars orbit. They burned to depletion to demonstrate the amount of second stage performance available after a 6 hour coast (that being a requirement of some defense launches).

Re:Best possible failure

[jimtheowl]

Let us never forget, so we can give Spaceman a speeding ticket next time we see him.

Re: Best possible failure

[Anonymous Coward]

Dude, the only speed limit in space is C!

Re:Best possible failure

[K. S. Kyosuke]

No, you're confused, that was the latest Ariane launch. ;)

Re:Best possible failure

[Headw1nd]

Musk wanted the farthest he could get, to show capability. If he could get out of the solar system he would have. Not to mention Mars is not really a commercial destination, but there has been a lot of interest recently in asteroids as a source of minerals. He's just shown the world he can get there with car-sized equipment for $90m.

Re:Best possible failure

[SamTombs]

Nitpick: It is Starman, not Spaceman.

Re:Best possible failure

[sysrammer]

Don't skimp on the metrics!

They used Imperial for the core.

This is good news.

[Gravis Zero]

Finding out potential problems in a design can be daunting task, especially when something going wrong causes it to explode. What this means is they have found how to improve the design and will likely factor this into other designs. It's only a true failure if you don't learn anything in the process.

The fluid was used in flamethrower tests

[Anonymous Coward]

They didn't have enough lighter fluid cuz they used it all on the tests of the flamethrower

Next time:

[thermowax]

Zippo.

There is no substitute.

Re:Next time:

[K. S. Kyosuke]

Funnily, the chemical compounds used for ignition of the Merlin engines are related to something coincidentally called "zip fuel".

Noting

[fahrbot-bot]

Musk is quoted as saying, "The fix was pretty obvious."

Too bad the problem wasn't and they lost the booster. That's, what, a $30M mistake?

I'll add that I watched the launch online and it was great. Watching the two side boosters land simultaneously was amazing. I actually got a little choked-up.

Re:Noting

[tdelaney]

~$5 million for the centre core IIRC, and it wasn't going to be reused in any case. All-in-all, fairly cheap in aerospace terms for valuable data.

Sometimes there's no substitute for actually trying things out and failing. Aiming to succeed but not being afraid to fail is one of the major reasons why SpaceX has advanced their development so quickly (even with a 5-year delay on original estimates for the first Falcon Heavy test flight).

Re:Noting

[pezpunk]

it's amazing how many people don't know what a test flight is for.

Re:Noting

[DamnOregonian]

I actually got a little choked-up.

Was hard not to. Felt like one of those "Holy shit, humanity... Holy shit." moments.
Shit coming back from space and landing without banging off the ground or splashing into the water... is pretty amazing. Even cooler that the entire thing is autonomous.

Re: Noting

[Anonymous Coward]

Automation is taking hard working American jobs! There should be a pilot on board flying those boosters back

Re:Noting

[K. S. Kyosuke]

It was a $0 mistake, rocket-wise. Barge-wise, some systems have to be fixed or replaced.

They used all the fluid testing their flamethrower

[Anonymous Coward]

They really shouldn't have used all the fluid on the flamethrower tests

May have been the descent, as you mention

[Anonymous Coward]

or possibly they used more TEA-TEB on the first ignition than they expected. I hope we find out which was the problem.

Non-news, ignoring actual news

[Michael Woodhams]

Elon Musk tweeted:

Not enough ignition fluid to light the outer two engines after several three engine relights. Fix is pretty obvious.

Somebody then turned those 19 words into an article, which /. then summarized to about 200 words. Furthermore, Musk's tweet didn't tell us anything he hadn't already said in the post-launch press conference.

There actually was some news in Musk's recent twittering, however: An extra drone ship is being constructed for the east coast, to be named A Shortfall of Gravitas.

Is this new news?

[BenFranske]

I don't know why the LA Times is reporting this as new news. I'm pretty sure I had heard by Wednesday or Thursday that the problem was the rocket rant out of TEA-TEB ignition fluid. Don't journalists watch press conferences and read analysis anymore? Does the CEO need to Tweet about it before they pay attention?

Re:Is this new news?

[Anonymous Coward]

It's last weeks news. Neither the LAT nor slashdot are ever on the ball these days. I just come here to grief.

Re:Is this new news?

[thegarbz]

Does the CEO need to Tweet about it before they pay attention?

I pointed this out in great detail on the discussions of the governor of Hawaii being unable to alert people that the missile strike was false due to not knowing his twitter login, but yes. Yes this is the world we live in. Journalists have been cut left and right. There's no longer armies of people to send to press conferences. Instead people automatically monitor twitter of key public figures of interest and then post something about the tweet.

It was similar with the tsunami warning in Alaska a few weeks ago. Not a single news outlet covered the story without a link or reference to some tweet. The only thing different here is that for a chance the tweet didn't come out faster than the news conference.

Re:Is this new news?

[sysrammer]

Citizen journalists indeed. Perhaps we should start a Committee of Correspondence.

Unlikely unit conversion

[Orgasmatron]

Whenever I see 328 feet, I know that someone said "about 100 meters" and the reporter multiplied it under the assumption that us yokels can't figure out what it means without their help. It really pisses me off when reading an article about something slashdot-worthy, like a rocket. We never went metric in the US, but you'd have a hard time finding one of us today who isn't bilingual enough to grasp 100 meters as easily as 100 yards or 300 feet.

On the other hand, if the SpaceX guy did the conversion because he knew that the moronic reporters would otherwise report it as "328 feet, 1.00788 inches", I withdraw my objection with a chuckle.

Re:Unlikely unit conversion

[Anonymous Coward]

but you'd have a hard time finding one of us today who isn't bilingual enough to grasp 100 meters as easily as 100 yards or 300 feet.

You have clearly never been to the Deep South.

Re: Unlikely unit conversion

[Anonymous Coward]

... Because your bigotry would be exposed.

Re:Unlikely unit conversion

[thegarbz]

We never went metric in the US

Actually you did in 1975. The Metric Conversion Act was signed into law making metric the preferred system for the USA. Unfortunately it also permitted the continued use of USA customary units.

A voluntary law is nothing more than a waste of paper.

Re:Unlikely unit conversion

[jbengt]

Actually you did in 1975.

Much earlier than that, in the mid-to-early 1800s, the US allowed metric units to be used, and the US customary units were defined in terms of metric units, which was codified in the Mendenhall Order of 1893. So, in that sense, you could say that the US has been on a metric standard for over 100 years.

Re:Unlikely unit conversion

[sysrammer]

"That's the great thing about standards. There's so many to choose from."

Gotta fill the tank... Dolt

[wolfheart111]

Before you go to f'n MARS.... gotta fill up that tank. Ain't no petrol stations on the way there.... dont give musk any IDEAS. Hmmmm maybe if we build... hmmmm

Re:Gotta fill the tank... Dolt

[necro81]

SpaceX's eventual plans to go to Mars utilize a different rocket engine - the Raptor. Among other differences from the Merlin enigne (used by the Falcon 9), the Raptor will have spark ignition: no need for these highly combustible lighter fluids.

Re:Gotta fill the tank... Dolt

[fox171171]

SpaceX's eventual plans to go to Mars utilize a different rocket engine - the Raptor. Among other differences from the Merlin enigne (used by the Falcon 9), the Raptor will have spark ignition: no need for these highly combustible lighter fluids.

Yeah, well then... Make sure they bring enough sparks with them.

lost technologies

[harvey the nerd]

What's left after they ran out of igniter fluid and crashed at 300 mph ? Zippo

Ran out of lighter fluid ? Get a Ronson

Ignition!

[mtaht]

A fabulous, deep, funny book on rocket fuels and the crazed chemists that developed them is called "Ignition!", by John D. Clark and forward by Isaac Asimov. Example text:

"Recommended lab attire for working with this volatile compound: Running shoes."

Ignition! has been long out of print. Thankfully archive.org has a copy here: https://archive.org/details/ig...

Re:Ignition!

[damnbunni]

Ignition! is back in print, on Kindle and in paperback.

Re:Ignition!

[mveloso]

Great book, I found it and read it a few years ago. I know nothing about rocket propellent, and afterwards I knew a little bit more.

He's really entertaining, and it makes for a good read. You have to be pretty good to make rocket fuel interesting for someone who knows nothing about rocket fuel.

If only they had enough for several four

[Anonymous Coward]

Perhaps the last try would have worked.

The future is now

[Locke2005]

I think the biggest difference between the government space programs and the private space programs is the private programs will be advertising supported. Much of the SpaceX Falcon Heavy launch was just designed to be good TV; next time expect the rockets to be emblazoned with Durex ads!

Re:The future is now

[K. S. Kyosuke]

You're not entirely right - perhaps the very first launch vehicle adorned with an advertisement was the booster that lifted the Zvezda module to the ISS. And that was a government flight, it's just that the government desperately needed more money.

Re:BeauHD Lacked Enough Spunk To Blow Load

[jimtheowl]

Your not one to criticize if you don't know that it is pronounced "Extra!".

https://en.wikipedia.org/wiki/...

"Extrie" is a joke from American Dad.

https://www.youtube.com/watch?...

It is as if everyone in America been raised by television.. Oh wait! Half of it.

Musk: "It's supposed to land?"

[Anonymous Coward]

Elon has figured out space, all right. Actually landing is another story.

Successful test

[DrYak]

It was a test flight.

And actually quite successful test :
  - It didn't destroy the launchpad
  - It didn't even blow up during the launch
  - As a bonus, even 2 out of the 3 core managed to land back safely.

Yes, everything didn't work out as planned (they planned to recovery the 3rd core, but it crashed).
Still, everything that is needed to launch payload is already working.

Basically, to be useful, the Falcon Heavy just needs not to blow up until it has successfully delivered it's payload at the targeted orbit.
Then even the 3 cores could be blowing up, it won't hamper the launch mission.

In other words, even if it performs exactly as the test including the destruction of the third core, the Falcon Heavy will be able to successfully launch the couple of sattelites that are planned on its next launch / first commercial mission.

this is one of those "we have to do it to see... and we might not even get it right the second... or third... or fourth time."

Now the best part it that Falcon Heavy is functional enough that they can keep doing these times, while at the same time being paid to launch satellites.
Again, for now, for SpaceX, the commercially important part is what happens until the payload has been delivered (satellite has been placed into orbit, or some next stage is able to propel some NASA experiment to transfer to Mars' orbit, etc.).
Everything that happens afterward (including the landing of the reusable cores) is "added bonus".

In the long term, once the re-use will be as successful as with Falcon 9 rocket, that is going to help SpaceX reduce the costs of launches (their whole idea of "Slightly cheaper flights thanks to parts reuse") (in addition of the all the useful engineering knowledge that they can gain by analyzing the returned vehicle)
But for now Falcon Heavy is already 100% usable for commercial flights even in non-fully recovered way.

Re:Successful test

[MightyYar]

One thing that I don't see mentioned is that it would appear this was the first time they attempted to actually land using a multi-engine descent. All of the prior landings (not counting the one deliberately ditched at sea) used a single engine to stick the landing. They are eager to get multi-engine descent working because it will allow them to land boosters with less fuel.

Re:Successful test

[Anonymous Coward]

The Government Mission where the satellite was lost, was a high velocity descent, it used a three engine burn as well. That's the booster that ended up floating in the ocean that the Air Force had to go out and blow up.

Re:Successful test

[MightyYar]

Correct - I don't think that counted as a "landing", or even an attempting landing... the intent was always to have it descend into the ocean. It sounds like this mission was their first attempt to actually land using the three-engine burn.

Ronsonol.

[sabbede]

Shoulda kept some handy.

Ignition fluid, really ?

[cwesley]

Coming from Musk, my first instinct is to grin and assume ignition fluid is the equivalent of blinker fluid.

Re:BeauHD Lacked Enough Spunk To Blow Load

[Anonymous Coward]

Isn't there a TV show that has the catchy tagline, "Extra! Extra!"?

Ask why again

[Anonymous Coward]

First why: "we ran out of starter fluid".
Ok, so why did this happen?
Repeat until have a clear picture

Was this a dog ate my homework, or something unexpected in the mission profile?
If the later, did a different dog get different homework?

SpaceX doesn't need to become NASA studying things to death instead of flying,
  but an after the fact deep study of the process that led to the story would be useful.

It is great that they know so quickly the first cause,
I look forward to the rest of the story.

Light the Candle

[necro81]

for those of you wondering: just how hard is it to light a rocket engine, when it is spewing tons of highly combustible fuel and oxider per second, Scott Manley provides a handy video on rocket ignition technology.

Not everyone believed in Musk

[kaizendojo]

For anyone that missed the interview on 60 Minutes a while back before the FH launch, it's extremely interesting to see Musk's reaction when the subject of resistance from Neil Armstrong and the late Gene Cernan's testimony to Congress. He got very emotional when pressed about the disparaging comments about the program were made and you could tell that it really hurt him personally when his heroes dissed him. It's one of the few times I have ever seen Elon Musk let something 'get to him' and it shows a human side you don't often see. Nice to see how personally vested he is besides the huge monetary investment. Remember that when he started SpaceX, he invested half of his assets from the PayPal sale despite everyone telling him he would likely end up losing it all. Buzz Aldrin, Neil's partner on the Moon, was at the FH launch. As far as I can tell, Armstrong hasn't commented on the launch. https://www.youtube.com/watch?... around 2:21

Re:Not everyone believed in Musk

[lengel]

Buzz Aldrin, Neil's partner on the Moon, was at the FH launch. As far as I can tell, Armstrong hasn't commented on the launch.

https://www.youtube.com/watch?... around 2:21

Ummm...... are you making some weird attempt at humor here?

Re:Not everyone believed in Musk

[kaizendojo]

OMG! WTF! I meant to say that "As far as I can tell, Armstrong wasn't commenting about THIS launch." Meaning they were more about BFR...My brain obviously disengaged. Holy crap I wish I could /. had an edit feature. Thanks for catching that and giving me a chance to clarify before more people saw it and thought I was dissing Neil (as much as I disagreed with some of his testimony).

Re:Not everyone believed in Musk

[cmdr_klarg]

Neil Armstrong won't be commenting, considering he died in 2012.

Re:Not everyone believed in Musk

[kaizendojo]

Please read my reply to the first person who pointed out my error which explains this.

I am interested to know why stater fluid ran out

[c8663]

Does anyone have any insight on why the core booster ran out of starter fluid and was not able to restart the needed 3 engines?

Is it possible that the core was shutting down and restarting engines during the accent to save fuel for when the side boosters separated and therefore used up too much starter fluid?

What would be really impressive....

[Eravnrekaree]

It is amazing what Musk has done. Still, Rocket technology, isnt exactly the most sustainable thing, when you consider the amount of resources which are used. Its also, kind of low tech, we are talking explosions and so on here. What would really be an advance is an anti-gravity electromagnetic drive of some kind powered by clean energy extracted from the aether without the use of dirty nuclear and fossil fuels. Pull that off and then I will be REALLY impressed.

Re:What would be really impressive....

[sysrammer]

I agree. I don't think Michelson-Morley was the last word on the subject.

Re:BeauHD Lacked Enough Spunk To Blow Load

[SamTombs]

I don''t know the origin of the phrase, but it predated American Dad by decades - my Dad used to sing it out when I was a kid, back in the early '60s.