
SpaceX Falcon rocket explodes on landing after delivering satellite to space - FrejNorling
http://www.bbc.com/news/science-environment-35340734
======
marvin
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.

~~~
dwc
> 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.

~~~
thatswrong0
I guess it depends on what you mean by significant. It's true that,
inherently, space flight is risky business.[0] This is new technology, so of
course they are going to continue to uncover weaknesses even much further down
the line once they start hitting a higher success rate.

But for the tiny bit of imperfect: the same could have been said for the space
shuttle, and that had people in it. And its fragility was a fundamental to its
design (it rode exposed on the fuel tank with its critically important heat-
absorbing tiles). And the shuttle still had a decent success rate!

I would argue that these failures are less fundamental to the design of the
rocket. And the difference is that if, in the future, you have that 1/100
failure on landing, it's only a loss from a cost perspective, not a human one.

[0] [http://i.imgur.com/ei3h1B7.png](http://i.imgur.com/ei3h1B7.png)

------
smegel
> 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.

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

~~~
baq
and the "explosion" is borderline, it's very close to just "burns really
fast", especially when you see what's left after the fire goes out:
[https://pbs.twimg.com/media/CY8-PdyU0AABqaa.jpg:large](https://pbs.twimg.com/media/CY8-PdyU0AABqaa.jpg:large)
(there's quite a lot of rocket left)

~~~
grey-area
That's a trick of perspective and scale, you are not seeing a rocket but one
landing leg intact attached to the engine block. The tube exploded as you'd
expect when it fell over and disintegrated.

Not really important though, they got the hard part right.

~~~
animal531
I'd work on engineering that, if possible. I mean if 10% of rockets fall over,
but you could get them to not explode then you'd still be up.

~~~
mikeash
I think people have a hard time grasping the scale of this stuff, and
therefore the fragility involved.

Getting the rocket to survive falling over is extremely difficult. It can't
even survive normal flight loads without the propellant tanks being
pressurized, because it needs the extra rigidity to avoid collapse.

The margins involved are extremely slim. For a more familiar point of
comparison, consider that a 747-400 (which is about as long as a Falcon 9 is
tall, not that this means a whole lot) weighs about 180 tons empty, and can
carry about 170 tons of fuel. The Falcon 9 first stage weighs around 25 tons
empty, and carries about _400 tons_ of fuel and oxidizer. (Note that numbers
are approximate, since official numbers are hard to come by.) That means that,
sitting on the pad and ready to go, a Falcon 9 first stage is about 95% fuel,
and 5% everything else. That 5% has to account not only for fuel tanks, but
engines, hydraulics, support structure to hold up the ~100 ton second stage
and payload, landing legs, and everything else that makes it a rocket and not
just a pair of tanks.

Now you bring it back, let it fall over, and catch it in a way that doesn't
break it. This is something about as tall as a decent-sized office building,
with a roughly zero tolerance for sideways force of any kind. Imagine tipping
over the Statue of Liberty and catching it without bending anything.

It's orders of magnitude easier to make sure the rocket doesn't fall over in
the first place. You want to concentrate your efforts where they'll have the
best return, and in this case there's no contest, it's not even close.

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

~~~
tw04
If that isn't tongue in cheek, you're insane. There's a laundry list of
companies that are competition to them, including two of the largest defense
contractors in the world.

[https://en.wikipedia.org/wiki/List_of_private_spaceflight_co...](https://en.wikipedia.org/wiki/List_of_private_spaceflight_companies)

~~~
davej
Not sure it was meant literally. I took it as more of a jibe at the quality of
existing space companies (and Blue Origin).

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

~~~
Havoc
Not enough lens-flare.

~~~
jedberg
Easy enough to add in post.

------
ChuckMcM
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
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.

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

~~~
eric_h
especially since it seems to have hit the bullseye on the center of the barge
(maybe missed dead center by a few inches).

~~~
JustSomeNobody
You can tell it missed by a few inches from the video?

------
codecamper
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?)

~~~
usrusr
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.

~~~
codecamper
3 axis table? Do you mean that the platform would be able to shift either way
to keep it from wobbling over? That seems hard given that a rocket is tall &
skinny.

How about a massive electromagnet underneath?

~~~
usrusr
Tall and skinny is exactly what you would want for dynamic balancing.
Unfortunately, an empty booster would have a very low center of gravity
compared to the external shape.

------
sushirain
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
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.

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

~~~
mabbo
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.

~~~
mrfusion
It fills with helium as it empties out the fuel.

~~~
mabbo
In that case, I have no idea why it exploded. :)

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

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

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ohitsdom
An exact bulls-eye, absolutely amazing.

------
jffry
See also:
[https://news.ycombinator.com/item?id=10923582](https://news.ycombinator.com/item?id=10923582)

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

~~~
elif
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.

------
sebringj
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
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
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.

~~~
Grue3
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.

~~~
brianwawok
So if you launch out of Cali going west and separate stage 2 300 miles out....
What is under you to land on?

~~~
mikeash
Not to change your overall point, but you almost never launch west. When
possible, you want to launch east, to gain the benefit of the Earth's
rotational speed. Sometimes you launch north or south so you can go into a
polar orbit which allows viewing more of the Earth. But there's pretty much no
reason to launch west. One exception to this is if your launch site is located
in a place where that's the only option, which is why Israel does it like
this.

For American launch sites, you have KSC for launching east, and Vandenberg for
launching south. (North and south are equivalent in terms of which orbits they
can reach, so you don't need both.) Vandenberg can be used for launching west,
but pretty much never is, unless you count ICBM tests and the like.

~~~
brianwawok
Well the launch Space-X launch was South-West, clearly not over any land.

~~~
mikeash
Southeast, not southwest. But yes, as I said in the original comment, it
doesn't change your overall point.

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

~~~
ethbro
Also, if you deployed mitigation methods prematurely, then it stops the drive
for improvement and tuning of the core landing functionality.

Quick deploy cushions or other "Oops" enhancements might feature into the
final version of the barge, but for now I think they're still trying to
maximize the landing success rate. Better not to split engineering resources
when the most important problem can still benefit from optimization.

~~~
JulianMorrison
They are landing on Mars. That's the ultimate point. Mars does not have
airbags.

------
Havoc
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
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.

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morsch
At least the barge looks like it should be reusable.

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

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

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

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

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ck2
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
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).

~~~
ck2
Yeah but if a rocket can so easily explode just by falling over, I'm not sure
there are any legs I trust it to land on.

I mean what if the legs were damaged during launch somehow, how exactly would
it get back down safely other than just dropping it in the ocean completely?

~~~
zardo
>I mean what if the legs were damaged during launch somehow, how exactly would
it get back down safely other than just dropping it in the ocean completely?

Then it blows up and you fix the extremely serious problem that threatened the
primary mission by damaging the rocket during launch.

------
grogenaut
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
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.

~~~
grogenaut
I figured salt would be the reason. Also the thermal stress of quenching it.

Forgot about the mars aspect.

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

------
madaxe_again
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
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/](https://www.instagram.com/p/BAqirNbwEc0/)

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

~~~
neolefty
In this case, they had enough fuel to return to the launch site but they used
the barge because they couldn't get permission to return to Vandenburg.
[http://observer.com/2016/01/breaking-spacex-fails-a-third-
ti...](http://observer.com/2016/01/breaking-spacex-fails-a-third-time-to-land-
falcon-9-rocket-on-drone-ship/)

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

~~~
rplnt
The title presented it as if it were a single craft at all times. Of course
"delivering 2nd stage to space" would sound silly, but I'm sure the title
could be worded factually correct and still be simple and informative (as
titles should be).

~~~
sageikosa
"SpaceX booster explodes during recovery, payload delivery unhindered"

