
Smoke seen for miles as SpaceX Crew Dragon suffers anomaly at Cape Canaveral - jbuzbee
https://www.floridatoday.com/story/tech/science/space/2019/04/20/smoke-seen-miles-spacex-crew-dragon-suffers-anomaly-cape-canaveral/3531086002/
======
lchengify
Some thoughts on the initial images from /r/spacex (great community):

1\. The orange smoke [1] is the color of Nitrogen Tetroxide, which is the
hypergolic fuel that Crew Dragon uses. The normal reaction in the Draco
engines in the Crew Dragon is Nitrogen Tetroxide (N2O4) and methyl hydrazine
(CH3(NH)NH2) [2]

2\. The prior grey smoke might mean the engines were already firing for the
test, which would rule out something like a tank loading error or something
else with the ground crew.

3\. Boeing had a hypergolics + Launch Escape System anomaly and it pushed
their program schedule back 6 months. [3]

4\. Eric Berger (Reporter for Ars Technica) indicating it may have been a
serious incident. [4]

/r/spacex thread:

[https://www.reddit.com/r/spacex/comments/bfhm2c/on_april_20_...](https://www.reddit.com/r/spacex/comments/bfhm2c/on_april_20_an_anomaly_occurred_at_cape_canaveral/)

[1]
[https://pbs.twimg.com/media/D4oMNJmXsAAv_7B.jpg:orig](https://pbs.twimg.com/media/D4oMNJmXsAAv_7B.jpg:orig)

[2]
[https://en.wikipedia.org/wiki/Draco_(rocket_engine_family)](https://en.wikipedia.org/wiki/Draco_\(rocket_engine_family\))

[3] [https://spacenews.com/boeings-starliner-launch-abort-
engine-...](https://spacenews.com/boeings-starliner-launch-abort-engine-
suffers-problem-during-testing/)

[4]
[https://twitter.com/SciGuySpace/status/1119730184544976897](https://twitter.com/SciGuySpace/status/1119730184544976897)

~~~
yread
From the Ars article

> Boeing had intended to complete the test of its abort system last summer but
> has yet to reschedule the flight 10 months later, apparently due to
> complications from this accident.

So it's probably more than 6 months

~~~
trevyn
Are Boeing and SpaceX complication rescheduling timelines usually comparable?
(Serious question)

~~~
sandworm101
Yes because they both work for the same customer (nasa) who will determine the
type of process needed. When it comes to human spaceflight, nasa decides the
pace of the investigation (number/nature of reports etc). They take accidents
on the pad exectly as seriously as accidents in flight.

------
joeyrideout
It is important to note that "Crew Dragon" is the name of the capsule. No
people were on board. It was a test.

~~~
hinkley
Maybe the PR department should have more say in the naming process.

~~~
zlsa
They did. It used to be called Dragon V2.

~~~
hinkley
Time for a new hire in the PR Dept :)

~~~
zoeysaurusrex
They’ll take advice from us when we stop naming things like BouncyCastle[1]

1\.
[https://www.bouncycastle.org/java.html](https://www.bouncycastle.org/java.html)

~~~
mrec
Or Hamcrest ([http://hamcrest.org/](http://hamcrest.org/))

Still have no idea what they were thinking with that one. Apparently it's an
anagram of "matchers". Ooooookay.

------
Waterluvian
"The initial tests completed successfully but the final test resulted in an
anomaly on the test stand."

I'm not saying this is spin, but it sounds like how you'd spin something like
this. Basically, the tests worked until they didn't. And that one therefore
became the final test.

~~~
craftyguy
It could also be that the last test they planned to execute resulted in the
'anomaly'.. Not every public communication is subterfuge even though the
armchair detectives in the HN comment section always seems to think it is.

~~~
colechristensen
"Anomaly" implies this is not the case.

~~~
craftyguy
No, anomaly means there was an outcome which was not expected. It says nothing
about how many tests they were going to execute (if any), what the unexpected
outcome was, or what the lead test engineer ate for breakfast that morning.

~~~
usrusr
That's the dictionary definition of "anomaly". But that's not the interesting
part, what's tickling us armchair detectives is how it got into the press
release: "anomaly" is a bit of an anomaly itself, most people would never use
that term unless specifically to play something down. That surely is no proof,
enough to inspire speculation.

~~~
xattt
Speaking of speculation, there could be quite a few speculators in this thread
that are invested in SpaceX. The downplaying of the actual event could be
their own way to shape the stock price.

~~~
camjohnson26
Isn’t SpaceX private?

------
CaliforniaKarl
In case it's relevant, here's a 1958 NASA film on the hazards of the
propellants (various hydrazines) and the oxidizer (nitrogen tetroxide) that
were used at the time. As mentioned in another top-level comment, the Crew
Dragon uses nitrogen tetroxide as an oxidizer.

[https://www.youtube.com/watch?v=Zha9DyS-
PPA](https://www.youtube.com/watch?v=Zha9DyS-PPA)

~~~
hobs
If you enjoy this type of stuff, a great read is: IGNITION! An Informal
History of Liquid Rocket Propellants
[https://library.sciencemadness.org/library/books/ignition.pd...](https://library.sciencemadness.org/library/books/ignition.pdf)

~~~
sitharus
They’ve recently done a second paperback edition so you can even get a
physical copy! It’s a great read for anyone, and shows the crazy risks taken
in the early rocket programs.

------
gingernaut
Here is an alleged video of the event, there's a large explosion:
[https://twitter.com/Astronut099/status/1119825093742530560](https://twitter.com/Astronut099/status/1119825093742530560)

~~~
lchengify
Interesting. The voice in the video is mid countdown when it happens ("Ten,
Nine....expletive") which implies the Super Draco engines hadn't fired yet.

If it's something like a pressure issue, it could be similar to what happened
to AMOS-6, where there was buckled liner in a COPV [1] tank that caused a
liquid oxygen buildup [2]

Someone on reddit captured the frames before and after, it looks like it's
originating from just near one of the Super Dracos [3].

[1]
[https://en.wikipedia.org/wiki/Composite_overwrapped_pressure...](https://en.wikipedia.org/wiki/Composite_overwrapped_pressure_vessel)

[2]
[https://en.wikipedia.org/wiki/Amos-6](https://en.wikipedia.org/wiki/Amos-6)

[3] [https://imgur.com/G0iE6Rr](https://imgur.com/G0iE6Rr)

~~~
_Microft
AMOS-6 suffered from a problem with a Helium Composite over-wrapped pressured
vessel (COPV) that most likely had a liquid oxygen intrusion into the
composite layer which due to the cold temperature of the helium created oxygen
ice that violently reacted with the composite when friction ignited the
combination. (Fun fact: as far as I know a liquid-oxygen drenched cigarette
basically explodes when lit).

Afaik there is no Helium COPV on Crew Dragon.

 _Edit:_ after checking because of _Someone_ s comment, it turned out that
cigarettes do _not_ explode when drenched with LOX, they just burn brightly
not unlike a flare.

~~~
Someone
_”a liquid-oxygen drenched cigarette basically explodes when lit”_

Doesn’t seem to be true. At the least, that’s isn’t guaranteed.
[https://www.youtube.com/watch?v=t48QWjtoVfw](https://www.youtube.com/watch?v=t48QWjtoVfw)

------
TallGuyShort
In spaceflight, does 'anomaly' ever refer to something other than an explosive
fireball? Because I've heard that term used for rocket explosions and I get
that vibe from this announcement, but... But could it be that the computer
just tanked and now they're going through a core dump? Would that be an
'anomaly'?

~~~
gmueckl
Ideally, computers inside rockets don't crash. The software should be that
good when you're letting it handle tons of explosive fuel. Then again, Ariane
5 did happen...

~~~
jakeinspace
That's the idea. I'm working on flight software for Orion, and there are many
levels of redundancy, both in design and process, that are put into the
software architecture. It's extremely expensive, but flight software is still
a drop in the bucket compared to mechanical, propulsion, and electrical
systems. It should have an expected failure rate much lower than the physical
systems, and should never be on the critical path. We're not doing fancy
stuff, it's just gotta be robust and fault tolerant.

~~~
jacquesm
> just

The deadpan delivery really does it.

~~~
jakeinspace
Yeah well, it's definitely not trivial. I just mean that most of the problems
we're implementing have been solved decades ago (inverse kinematics, control,
comms, etc). When you actually need to get all of those functions working in a
hard real-time system, of course there are enormous engineering difficulties.
In my limited experience, these mostly manifest as extensive testing and
formal verification, to the extent to which that is possible.

Check out NASA Core Flight System if you're curious, it's an in-house
framework and abstracted OS layer meant to support hard real-time flight
systems.

~~~
jacquesm
Definitely will do that, thank you for the pointer. Reliable software design
is something I've been interested in for a very long time and it is amazing
(to me, at least) how much we already know and yet refuse to put into
practice. I think a big part of this is that speed is sexy and reliability is
not.

------
abledon
After the success of the Falcon Heavy a couple days ago, I'm actually
surprised there weren't more hiccups in SpaceX activity. They are pushing the
limits of spaceflight technology, there are _bound_ to be setbacks like this.
A roadmap with no errors like this is highly improbable. Amen for rigorous
testing.

~~~
rayiner
I think SpaceX is great. But how are they “pushing the limits of spaceflight
technology?” The SpaceX Merlin engine uses the same basic RP-1/LOX cycle as
the Saturn V’s first stage engine, which is more than half a century old now.
Rocketdyne’s engine produced about 7-8 times as much thrust (which is why
SpaceX needs 27 engines on three boosters for a Falcon 9 Heavy, versus 5 for a
Saturn V.)

(Here is the computing equivalent of what SpaceX is doing: creating a PDP-11
with modern technology, that’s maybe 75% as fast, but at a fifth to a tenth of
the cost.)

A more accurate summary is SpaceX is retreading well-worm ground that was trod
before many of us reading this article were born, bringing modern materials
and manufacturing capabilities to bear improving the same basic designs.
That’s cool. But that’s not pushing the boundaries of space flight technology.

~~~
krisoft
You are asking: how are they “pushing the limits of spaceflight technology?”

Let's not go futher, just concentrating at the incident in question. The
anomalous test happened on a location named "Landing Zone 1". That's not a
thing any other rocket company has. Why? Because they don't land their
rockets.

It happened with a space capsule fished out of the brine. No other company
reuses their space capsules in such a way.

The detonation very likely will be found to have something to do with the
SuperDraco system. Which they originally designed there to enable propulsive
landing on dry land. The russians have their kick engines, sure, but that's
not really same as hover landing, isn't it? Why did they plan that? For rapid
reusability.

So yes, if you ignore all the things they did for reusability, then they
indeed are not pushing the limits of spaceflight technology.

~~~
rayiner
> Let's not go futher, just concentrating at the incident in question. The
> anomalous test happened on a location named "Landing Zone 1". That's not a
> thing any other rocket company has. Why? Because they don't land their
> rockets.

Parachute landing a crew pod into the ocean is something we first did the year
my dad was born.

> Which they originally designed there to enable propulsive landing on dry
> land.

We landed an entire orbiter like an airliner three years before I was born.

~~~
grecy
> _Parachute landing a crew pod into the ocean is something we first did the
> year my dad was born_

You're getting confused between the tiny pod that people sit in - which
basically _does_ nothing, and the actual rocket, with all the flames and
gasses and actually make the pod go somewhere.

Nobody has ever landed and reused the rocket before SpaceX

> _landed an entire orbiter like an airliner three years before I was born_

Yes, a thing with wings landed using lift from the wings. It did not use
rockets for propulsive landing like SpaceX have designed.

------
disillusioned
Well, it sure LOOKS like a total loss based on this video:
[https://twitter.com/Astronut099/status/1119825093742530560](https://twitter.com/Astronut099/status/1119825093742530560)

(Can confirm that this Twitter account is a real person who works at KSC.)

------
speeq
As much as I hate seeing setbacks and delays to commercial crew, it's best to
have these failures early on in the program before they risk the life of
astronauts and personnel.

------
keyle
This is why you have tests. So overall, if it saved a real loss in the future,
it's a win.

------
falcor84
After watching the Apollo 1 disaster scene in First Man, I'm very glad to read
that they're now doing this extensive testing without humans on board.

~~~
craftyguy
Well, not pumping the capsule with 100% oxygen definitely helps too.

~~~
andy_ppp
Does it have to be 100% oxygen due to pressure or?

~~~
ls612
That’s slightly misleading. Originally they put 1 atmosphere of pure O2 in the
Apollo capsule. This proved to be a great environment for fires. After that
they pressurized the capsule with 5 psi of pure O2, which is about 1/3
atmospheric pressure.

~~~
andy_ppp
What’s wrong with air is what I’m asking? Are the pressures in the cabin too
extreme?

~~~
empyrical
If you're wondering why there wasn't nitrogen mixed in, it's because the
additional systems+tanks for handling nitrogen would've added more weight to
the spacecraft.

This video goes in to a bit more detail:
[https://www.youtube.com/watch?v=FvA7N_j_8os](https://www.youtube.com/watch?v=FvA7N_j_8os)

------
f2f
I don't like setbacks, but I fully endorse rigorous testing.

------
MarcysVonEylau
This reminds me of the Apollo 1 incident [1], happily without any casualties.
If it turns out to be a design fault, I'm glad they caught it now.

[1]
[https://en.wikipedia.org/wiki/Apollo_1](https://en.wikipedia.org/wiki/Apollo_1)

------
fao_
I've spent a few hours reading SCPs so now I really have no idea what the hell
an anomaly would mean in this context.

Just a small computer glitch or, things firing/smoking when they shouldn't, or
something more drastic?

~~~
krisoft
Computer glitch? That's an anomaly.

Things firing/smoking when they shouldn't? That's an anomaly too.

Pressure reading slightly out of predicted range? Also anomaly.

Everything went kaboom? That is also an anomaly, as long as that wasn't the
plan.

Basically everything where expectation and reality do not meet.

------
setquk
This is why we have tests. This is the same as a unit test failure. Except it
costs a lot more when something goes red in the launch sector.

------
Mizza
Does this release a huge carcinogenic cloud over Florida?

~~~
MertsA
No, it'll form nitric acid as it reacts with moisture in the air and be
neutralized as it reacts with the environment. Nitrogen tetroxide is used as a
hypergolic oxidizer because it's very reactive. It'll react with basically
most anything that can be oxidized so it's not going to hang around for too
long.

~~~
Mizza
What about the methyl hydrazine?

~~~
MertsA
There was no or very little monomethylhydrazine released. If there was, it
would have reacted with the nitrogen tetroxide. Since it's hypergolic, it
doesn't need to be under high temperatures or pressures to react. Just the two
substances coming into contact will cause them to react.

~~~
Someone
Explosions tend to disperse material in uncontrolled ways, so I doubt the two
substances got mixed perfectly. Chances are not all monomethylhydrazine
reacted with the nitrogen tetroxide.

~~~
MertsA
Unfortunately I can't edit the previous comment anymore but you're right.
Originally I was under the assumption that the conjecture that the propellant
valve failed or started leaking upstream from it was correct. However, it
appears that the entire vehicle exploded before the SuperDraco test even
started. Since it wasn't just leaking out of a damaged engine, my assumptions
about roughly complete mixing were wrong. There's very little chance that
there wasn't a decent amount of MMH released as well.

------
Iwan-Zotow
Why a red smoke? Melange?

------
bfung
yay for testing!

------
sebringj
"SpaceX Crew Dragon pad testing finds anomaly delaying launch" sounds more
accurate and less distressing.

~~~
sebringj
Hmm I just saw the video and the test was distressing as it completely blew up
on the pad but without crew of course.

------
netsharc
Calling it anomaly smells of corporate newspeak to me, also it makes me think
of this:
[https://www.youtube.com/watch?v=3m5qxZm_JqM](https://www.youtube.com/watch?v=3m5qxZm_JqM)

Call it "malfunction discovered during testing", could you not?

~~~
kbutler
Just space flight technical jargon:

Nominal - as expected (no more than nominal deviations from expected
parameters)

Anomaly - something unexpected

~~~
interestica
Performed nominally. Performance anomaly.

Not sure which I overheard.

~~~
grkvlt
You would never say 'nominally', rather just 'nominal' to avoid confusion on
noisy radio nets.

