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SpaceX Falcon rocket explodes on landing after delivering satellite to space

222 points| FrejNorling | 10 years ago |bbc.com

211 comments

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marvin|10 years ago

SpaceX actually got very close to sticking this landing. Sea conditions were reasonably rough, with 3-meter waves. It's also the first time SpaceX launches in fog, IIRC. Everything about the landing except the stuck leg seemed to be perfect.

So IMHO, the fact that the rocket exploded is not the most pertinent fact about this experiment. The main piece of news is that SpaceX is exceedingly likely to be able to recover rocket boosters intact from sea, even in non-perfect weather conditions.

smoyer|10 years ago

As a former gymnast, I like the sticking the landing analogy but a human (even on an unstable mat) has far more control over their balance point (we do much of our balancing by bending at the waist - if only the rocket had one).

In any case, I agree that this was very close. I've also spent a reasonable amount of time on "big water" and was specifically watching the attitude of the landing deck with respect to the horizon. I didn't see much movement of the barge (but that doesn't mean there wasn't some instantaneous movement that together with the force of landing exceeded the leg's load rating).

The other thing that's struck me is that the SSTO advocates could end up becoming irrelevant. Who's going to argue we need SSTO at all if we can recover and reuse all the stages anyway? Multiple stages will remain dramatically more efficient (Yes - I know we don't get space planes with two hour flight times from New York to Tokyo quite as easily).

Finally ... I just have to say "I LOVE THIS". I remember as a child watching the Apollo missions and, as an engineer, I haven't been this excited about a project for a long time. Isn't this exactly the type of thing we can rally humanity around? Who's going to argue that it's not a great accomplishment?

noobie|10 years ago

>It's also the first time SpaceX launches in fog

Musk said the "root cause may have been ice buildup due to condensation from heavy fog at liftoff."

ctdonath|10 years ago

There's a pragmatic difference between recovering the booster over some period of time, vs literally parking the booster right where it took off & ready to re-launch within hours/minutes.

dwc|10 years ago

> Everything about the landing except the stuck leg seemed to be perfect.

And there's the issue: it only takes a tiny bit of imperfect to ruin a landing.

I do think that SpaceX is going to get to the point where they are recovering enough of their rockets to make it pay off. But there will probably always be a significant chance that some little thing will go wrong. Don't be fooled later by "we've landed 5 in a row" about that.

smegel|10 years ago

> explodes on landing

This is a pretty unfair characterization. It actually made the landing for most purposes, then a specific failure occurred - a leg failed to lock and it fell over. And yes, when a rocket falls over it will often explode.

myth_buster|10 years ago

As someone mentioned on Reddit

  Succeeded to land. Failed to stand.

mikeash|10 years ago

"Explodes after landing" would be more accurate, I think.

ars|10 years ago

> And yes, when a rocket falls over it will often explode.

Why? Why would a small hit make it explode, when the stress of going from orbit does not?

charleypyn|10 years ago

It's not an unfair headline. It did explode when it landed. This is not good, no way how you twist it.

JoeAltmaier|10 years ago

Speaks volumes for Mr. Musk's character that they're being completely open and honest about this problem. Turns the conversation from "What happened? What are they hiding?" to "Interesting Engineering problem. How can it be addressed?"

kardos|10 years ago

They don't have much in the way of competition to keep 'trade secrets' from

Animats|10 years ago

This is progress. They got a good landing, then the landing gear collapsed, and not because of a hard landing. Next time they'll have a design that forces the landing gear down and locked, ice or no ice. Somewhere down in Hawthorne, someone is probably freezing one of those mechanisms in a cold chamber right now.

This is way better than back in July, when the booster blew up because of a strut failure. That was a major quality control failure.

Rooster61|10 years ago

This just in: Elon Musk has reportedly terminated all employees who uttered the phrase "Break a leg!" before launch.

In all seriousness though, this was by and large a successful landing, not to mention that they successfully put their payload into orbit without a hitch. The number of things that have to go right to even get that rocket to touch down on the barge is mind boggling. Truly impressive, and bodes well for the future of SpaceX.

verytrivial|10 years ago

I like to think that with these videos SpaceX is also making a very worthy contribution to more realistic movie special effects.

Havoc|10 years ago

Not enough lens-flare.

ChuckMcM|10 years ago

That was pretty much exactly what I expected to see from the video given the description of a broken landing leg yesterday.

Elon's twitter comment about the ice is interesting because it adds some interesting twists. If the stage is icing up as it descends it would change the mass calculation, however it does not seem to shed ice when it lands in the video. He suggested that ice at launch may have interfered with leg locking, which would mean that ice survived travelling supersonically through the atmosphere. But hard to figure how that could be.

marvin|10 years ago

In an earlier re-entry video, the camera lens ices up during the re-entry burn, presumably due to water from the engine exhaust. So I don't think that re-entry is necessarily enough to heat up the stage enough to melt all the ice on it.

Symmetry|10 years ago

In this case the ice would have been protected by being enclosed or mostly enclosed by the leg mechanisms.

jsumrall|10 years ago

The rocket exploded because it fell over, not the other way around. Had one of the landing gears not malfunctioned, it would have been fine.

tetraodonpuffer|10 years ago

yeah, it feels the title this time should be rocket explodes AFTER landing, to give a better feeling of how close this was

codecamper|10 years ago

This is the second time something like this happened. Why not put 4 tall posts up - equidistant from each other - a square.

Then a wire net between the posts.

When it tips over, it can just fall into the wire net.... they could even have motors to unwind a little while it leans over on them to allow "soft catching" the rocket. Foam over the wires would help here.

Actually... why not skip the barge & the dramatic landing and just catch it with a big underwater net? I suppose getting the rocket wet with salt water is not good? (the inside is covered with liquid spill indicators which void the warranty?)

NamTaf|10 years ago

2 reasons:

1) As you say, salt water is bad. Do never go in salt water if you want metallic, electronic things to keep working.

2) The rocket can't withstand much, if any, load in longitudinal bending mode. It'll buckle like a toilet paper cardboard tube. This almost certainly includes under its own weight, if you were to 'catch' it at the top of the rocket and hold it on an angle. To design against that, you'd be adding way too much weight to the structure to make it worthwhile.

LewisJEllis|10 years ago

Rockets are more fragile than one might think, but even assuming that would work, it's significantly more useful to be able to land just about anywhere that's flat.

Also, we don't have giant posts and nets waiting for us on Mars.

bobbles|10 years ago

I guess if you optimised for a net 'landing' you'd also be losing the ability to realistically land anywhere you want, since you'd have to have a net there. learning this way would potentially open up any flat surface

usrusr|10 years ago

My initially reaction were similar ideas, but thinking about it some more i am not sure if the empty tank could tolerate the stresses from getting caught in a net. And with a landing strut failure like today, you would probably lose the engines even with the tank not completely tipping over.

But SpaceX seem to be exceptionally good at control systems, fast and precise automated planning. Maybe they will just skip the level of passive rocket catcher structures and intend to move directly to a three-axis actuated landing table? A system like that that could take responsibility for a tiny little amount of deceleration (think extra suspension) and a fair bit of balancing completely outside of the mass budget of the rocket.

ansible|10 years ago

Anything other than a perfect vertical landing is likely to result in damage to the structure and components. Thus negating most of the value in landing the 1st stage.

Sea water is also highly corrosive to many materials.

sushirain|10 years ago

Perhaps landing into a tank of non-corrosive liquid would prevent such collapses? Or on some kind of "glue"/alloy that quickly freezes.

You can also have spearguns firing cords from the top of the rocket to the ground after landing, to hold it.

vulpes|10 years ago

One of the main stated goals of vertical landings is so they can do it on other planets/bodies. There are other proven methods of reuse when you have a benefit of an atmosphere and/or infrastructure.

A working vertical landing mode that can also be used on Mars, Moon and other objects in the solar system is one of the major mission at SpaceX. Shipping a giant vat of non-corrosive/conductive liquid to another planet does not appear viable.

pazimzadeh|10 years ago

I was thinking that same thing. Maybe not water but some kind of non-conductive gel?

jaffee|10 years ago

I want to know what exploded - I wouldn't have expected it to have very much leftover fuel at that point...

CarolineW|10 years ago

    ... the first stage of Falcon 9 v1.1 is
    capable of holding 119,100 Kilograms of
    Rocket Propellant 1 and 276,600 kg of
    Liquid Oxygen.
(From http://spaceflight101.com/spacerockets/falcon-9-v1-1-f9r/ )

So even if it's 99.9% empty, it still can have 120 kgs of rocket fuel. That'll go with a bang.

And it's unlikely to land with only 0.1% of its fuel left - that margin is too small to be attempting a soft landing, so I'd expect it to be a lot more. Then compare with just 5 gallons (probably US gallons, about 19 liters, close to 17 or 19 kgs) of ordinary gasoline:

* https://www.youtube.com/watch?v=C72bv2YhZ6A

* https://news.ycombinator.com/item?id=10924521

krisoft|10 years ago

The rocket runs out of usable fuel, but that doesn't mean that it is empty. If for no other reason the turbo pumps would probably get damaged beyond repair if you run the tank bone dry. Also it's not just fuel, but oxygen too in the right ratio.

mabbo|10 years ago

If you put a spark inside a full gas/petrol can, not much happens. Not enough oxygen. Half full? Still not such a big deal.

But empty the can, leaving behind just the fumes and the oxygen, and you have yourself a bomb.

My understanding is that the rocket here is a similar problem. It's a giant tube of explosive material. I wouldn't want to tap it with a hammer. And they've got it falling to earth at supersonic speeds, then calmly setting itself down on a barge at sea in 3m waves.

lmm|10 years ago

Rocket fuel/oxidiser together are pretty explosive (by their very nature) - even if it was just leftover vapour in an otherwise empty tank.

halviti|10 years ago

Is there a reason not to design the rocket with more legs, say 6 legs instead of 4?

ceejayoz|10 years ago

Weight. Every pound you use up on things like legs is a whole bunch of pounds you can't take to orbit.

ohitsdom|10 years ago

An exact bulls-eye, absolutely amazing.

DanielBMarkham|10 years ago

Congrats to the guys at Space-X! Love to see me some hardware blowing up.

Seriously, I'm not being facetious. We make aeronautical hardware safe by flying the crap out of it. That means lots of flights. Lots of accidents. The more you fly it, the more problems you have, the safer it is.

Congrats guys. Every time gets closer and closer. A few more and you'll have this thing nailed. That's good for all of us.

AaronM|10 years ago

They are getting really close to sticking a landing on a barge. I would be surprised if we don't see a successful barge landing this year.

rezashirazian|10 years ago

Am I the only one who was surprised by how violently the rocket exploded when it fell to its side?

elif|10 years ago

Put yourself in the liquid oxygen's shoes.

One second, you're chilling out at -207 C with your bros and some kerosenes, maybe even stopping off in near space--then, out of nowhere your containment vessel is compromised and you're evicted.. expected to just phase change and mix with all those common atmospherics.

I think I'd react the same way.

manicdee|10 years ago

Thin metal tube containing gaseous oxygen and kerosene, pressurised to 50psi.

I suspect there is also a termination system that deliberately detonates so as to control the mode of failure (i.e.: combust the dangerous stuff before it has an opportunity to mix with the other stuff and make things worse)

sebringj|10 years ago

They keep getting better so quickly! I'm in no way qualified to say this but I would have to guess the tip over after landing is a very trivial problem to overcome compared to atmospheric entry with 180 degree flip and burn to slow for landing. Go SpaceX!

niels_olson|10 years ago

I wonder if they've considered side curtain airbags to catch the rocket once it's really close like that, sort of like Amazon traps your item in 3 or 4 of those big bags, instead of lots of bubblewrap.

bantunes|10 years ago

Could someone explain to me why they attempt this? Wouldn't inflating a set of floating devices when it goes down the ocean an easier way of retrieving it? Or something other than this REALLY HARD TO PULL OFF maneuver? Genuinely interested.

benjaminl|10 years ago

The key thing to remember about rockets is that they are incredibly fragile. The rocket is about 15 stories tall and is designed for force to only be applied at the end either via the rocket engines or the landing gear.

Any type of lateral forces will irreversibly damage the rocket. As an illustration, extreme care is taken when the rocket needs to be transported on its side. Some rockets, not the Falcon 9, can't even be transported on their side without being pressurized.

So pretty much anything other than a perfect soft touch landing would leave the rocket unable to fly again. Anything touching the 3/16" thick skin of the Falcon 9, would cause the very least extensive refurbishment at the least, but more likely irreversibly damage the frame of the 15 stories tall 1st stage. So this rules out every alternative that has been suggested in this thread.

ruffmuff|10 years ago

Two main reasons I can think of: 1) Sea water is extremely corrosive. If your booster takes a dunk in the drink, it's going to be very hard to refurbish for another launch. Lots of components (electronics, valves, etc) would need to be replaced and the structural integrity of the tanks themselves may be compromised by rust.

2) Flotation devices attached to the booster = extra payload. It would be the canvas/dinghys AND compressed gas canisters for inflating them. This is arguably (a lot?) more weight than just landing struts + fins. Any extra payload on a rocket represents a massive cost and means less stuff you can haul for paying customers.

dchesterton|10 years ago

They want to use this tech to eventually land rockets on other planets so the rocket needs to be able to land upright. Short term it might be easier to land on inflatables but they're looking at the bigger picture.

ohyes|10 years ago

They want to be able to relatively quickly send it back into space. If they have to pull it out of the ocean and dry it out/fix it, I assume this makes their turnaround time less than ideal. Think what you do with a 747, it lands, a technician checks it out, it gets refueled, it takes off again. We'd be able to build things in space so much faster with that sort of round-trip lifting capability. I assume there are also implications for exploring other planets. This is my guess as someone who has not studied the issue closely.

JoeAltmaier|10 years ago

You don't want to carry heavy landing-maneuver gear to space and back. Thus the skeletal landing struts that were not-quite-strong-enough for rough seas.

Further, the ocean platform it was landing on was built to sustain heavy seas and stay relatively flat. Recovering a rocket bobbing in the waves could be much harder than this. Also a challenge: quenching a very hot engine in cold ocean water.

No, this platform-landing is probably one of the simplest, safest ways to recover/reuse a stage.

alkonaut|10 years ago

Rockets have always been able to land in the ocean more or less intact (i.e. without disintegrating). However, if the rocket is dipped in salt water, the restoration would be enormously expensive, so it needs to stay dry to be re-used.

Of course, you could just try to land it vertically on the water on some cushion and have more cushions deploy to make it tip over horizontally and float (all the time staying above the surface of the ocean). Such a solution isn't as compatible with recovery on dry land. If you want to do e.g. space tourism missions and land on dry land, the vertical landing seems better.

jsumrall|10 years ago

How do you expect it to be able to land on an inflatable raft? The point of landing the rocket is to reuse it, which is not possible if it falls over or gets wet.

Landing in the ocean is only done for certain types of missions, where its not possible to carry enough fuel to turn the first stand around a fly it all the way back to the launch site. Instead, they can carry just enough fuel to land wherever they are finished boosting the 2nd stage, to put it simply.

Already__Taken|10 years ago

Keeping it out of the sea water is a key part of reusability.

agumonkey|10 years ago

Or even a different kind of barge. A floating 'jar' rather than a flat surface, the thing could tip and not fall all the way.

startupfounder|10 years ago

Salt water isn't good for rockets. Once you solve this really hard problem of landing a rocket on a barge on a dynamic ocean you have a real competitive advantage.

el_zorro|10 years ago

The corrosion from the salt water would completely ruin the engines, obviating any benefits from returning the first stage.

Grue3|10 years ago

Yeah, I don't understand why they won't keep landing them on the ground like everyone else does. It's not like there's not enough space on Earth.

Medox|10 years ago

The landing could be made safer by something like cushioned walls that deploy towards the rocket after touchdown, to avoid such explosions. Think of a giant Christmas Tree stand like this: http://www.christmastreeland.co.uk/product_images/v/428/761_.... but with cushioned hooks on the barge. You can't always hope for all 4 legs to be in perfect condition, or that there aren't high waves in the ocean. That rocket is huge and seems to fall too easily, while a stand with hooks can't be too expensive, unlike a complete new rocket...

ceejayoz|10 years ago

Here's a side-by-side comparison of their three barge landing attempts: https://www.youtube.com/watch?v=IA7RzJckvQ4

I don't think big, over-engineered solutions really look necessary with the amount of progress they're making. Plus, there aren't any cushioned walls on Mars, which is SpaceX's eventual goal - use this sort of tech to touch down there.

cbhl|10 years ago

SpaceX eventually wants to land vehicles on Mars, where such landing infrastructure won't exist (at first).

(The Dragon cargo capsule has windows, despite cargo not needing to be able to look outside into space -- the windows are there because the capsule is designed to eventually carry humans some day.)

lmm|10 years ago

Bear in mind how large the rocket is, and that anything you put on the barge has to withstand being scorched by rocket exhaust.

Havoc|10 years ago

Why is the barge landing part so important to them? Seems unnecessarily difficult.

Big world out there...surely some suitable location can be found that is less wobbly for a start.

tempestn|10 years ago

They have a limited number of launch sites available to them, and the landing site is based on trajectory and fuel. Depending on the mass being launched, there will often not be enough fuel to turn around, and if you keep going, there's not much but ocean for a long way. Also, not any land will do. You need a pretty big, purpose-built space to land a rocket. With a barge, they can put that space where they need it.

LewisJEllis|10 years ago

Launches which send the payload beyond low earth orbit require too much velocity for the first stage to then turn around and make it all the way back to the launch site.

They put the barge downrange so less fuel will be needed to turn around and land, enabling first stage landings on beyond-low-earth-orbit launches.

StillBored|10 years ago

This has got to be a large part of why they were looking to launch from south Texas. that gives them a few hundred miles of gulf, and then they can land in FL.

morsch|10 years ago

At least the barge looks like it should be reusable.

JimmaDaRustla|10 years ago

Didn't it land, then fall over and explode?

Also, didn't this portion of the rocket land before the satellite was deployed?

yread|10 years ago

Amazing! If they want to use this tech for landing people on Mars (or anywhere) they still have some way to go though!

interdrift|10 years ago

Can't wait to fiddle with the landing source code after they release it in 10 to 20 years time :D

ck2|10 years ago

Would it be possible to have locking mechanisms directly in the dock itself?

ie. maybe the rocket descends several feet INTO the dock into a hole which then locks around the body of the rocket?

     ||
     ||
   ==||==  dock (which opens wide for decent and then closes)
     ||
     ^^

lmm|10 years ago

To be clear it's a barge, not a dock.

It might be possible, but we're talking about a rocket descending from hypersonic spaceflight; the accuracy is always going to be +/- a few metres. And the rocket would still have to have some kind of "hardpoints" that were strong enough to absorb the landing impact (you don't want to land smack on the delicate engine nozzles). A (relatively) big flat landing field and legs on the rocket itself seem like the smart approach (and Musk wants whatever technology they use to be usable for landing on Mars too).

joezydeco|10 years ago

That's asking for landing precision on the order of centimeters. While this landing was a bullseye (it's completely inside the inner yellow circle! wow!), they're probably not ready for that precision just yet.

You also need to land completely vertically, and it looks like the stage comes in at an angle on its suicide burn.

pjc50|10 years ago

Part of the problem is that the rocket walls are very thin and only suitable for vertical loads. You'd practically have to surround it with giant airbags to make that work.

They'll fix the landing leg problem somehow.

ceejayoz|10 years ago

I'd imagine that'd be even more complex and prone to failure.

grogenaut|10 years ago

is there a reason they can't like come to a stop over the water and then land in it and just expand some floats?

robotresearcher|10 years ago

1. Salt water is very corrosive, and would require extensive rebuild of the engines. 2. They want the tech to land on Mars before too long.

trhway|10 years ago

they just need airbags installed on the barge so the moment rocket lands the airbags inflate and hug the rocket.

madaxe_again|10 years ago

a) isn't this from last year? IIRC they had two failed barge landings. This looks like the first one.

b) The headline makes this sound like a miserable failure - still beats "fell into the ocean never to be found again", as all other current first stages do.

LoSboccacc|10 years ago

new launch. they need the barge for heavier payloads, because it costs much more fuel to go all the way back, so they'll keep testing.

Musk posted an early statement blaming icing due to bad weather conditions. https://www.instagram.com/p/BAqirNbwEc0/

...and of course press is overly sensationalistic. nothing new there to report.

NikolaeVarius|10 years ago

Its a failure because it didn't do what it is supposed to do.

Current first stages do exactly what they are supposed to do extremely well.

rplnt|10 years ago

Technically, it exploded well before it delivered the satellite.

edit to add some facts since this seems to be getting downvoted pretty quickly: Stage 1 landed and exploded at around T+10min, the satellite was deployed at T+56min. This was just two minutes after it was delivered on its final orbit. Both of those could be considered "delivered to space", neither of which happened before the failed landing.

ctolsen|10 years ago

You're being downvoted because it's a stupid assertion and it's "technically" not even the same craft at that point.

marshray|10 years ago

I think this is an interesting point. While I don't think we ought to rush out and change our terminology, I had not heard this anywhere else.

lmm|10 years ago

The satellite was comfortably above the Kármán line by the time of the failed landing.