
Orbcomm OG2 Falcon 9 Satellite Launch - cryptoz
http://www.spacex.com/webcast/?orbcommogbjuly14
======
cryptoz
Wow I can't believe this finally launched. So far so good! And of course, the
most exciting thing about this is the return attempt of the F9 first stage
core. I don't think that'll be covered in the webcast but we'll certainly get
video of it later. MECO successful.

Edit: r/spacex has good updates regarding the landing attempt

[T+27m]: Elon's jet and NASA plane circling a particular area...

[http://www.reddit.com/r/spacex/comments/2aany2/rspacex_orbco...](http://www.reddit.com/r/spacex/comments/2aany2/rspacex_orbcomm_og2_official_launch_discussion/)

~~~
ChuckMcM
Awesome, I noticed they were tracking the landing leg attachment points at
liftoff, so perhaps there is a new leg deployment system.

Also the note that 'kaboom' _after_ splashdown suggests that some part of the
landing mechanism didn't deal well the transition from flight to sailing. One
wonders what the temperature differential is between the landing first stage
and the ocean, on the one hand it might be hot (burning retro) on the other it
could be sub zero (cryogenic propellant usage).

Questions then are:

1) What was the mechanism that instituted the rapid disassembly of the landing
stage.

2) Would that mechanism come into play on a 'ground' based recovery?

3) What is the safe radius for ground recovery in the event of a structural
failure?

~~~
lutorm
Like trothamel commented below, the stage isn't designed for tipping over and
slamming into the water.

~~~
ChuckMcM
My problem with that theory/scenario is that the stage is designed to land on
its legs. When the test vehicles land they have very little angular momentum,
presumably these tests would mimic that. And if the momementum was managed,
then at engine shut off it would drop vertically into the water, and then fall
over as the counter pressure of buouancy was not stabilized by the landing
legs.

If you've ever seen loggers drop tree trunks in a river you can imagine what
that looks like, it starts out vertical, then reaches point where it displaces
enough water that it is essentially floating (but unstably so) and then
rotates to horizontal around the point on the trunk that is at the surface of
the water.

I totally understand that this isn't an intended landing mode :-).

Thinking about how they manage fuel load, it made me wonder how I would do it,
do you hover until you've exhausted all fuel? Or do you just shut off the
engine? And at flameout are you out of volatiles or just some volatiles (like
LOX)and do you have the 'gas tank' issue that auto mechanics deal with where
residual vapors can be explosive.

Would love to sit through the briefings on this stuff.

~~~
lutorm
The problem with your picture is that the empty stage is extremely light for
its volume so, unlike a log, it floats very high in the water. Floating
upright, most of it is above water and the top of the rocket is _high_ above
the water. The full launch vehicle is 220ft tall, and 2/3 of that is the first
stage.

------
grey-area
Looks like the landing was only partially successful -

Rocket booster reentry, landing burn & leg deploy were good, but lost hull
integrity right after splashdown (aka kaboom)

[https://twitter.com/elonmusk](https://twitter.com/elonmusk)

~~~
trothamel
I think it's hard to say that, yet.

The rocket isn't really made to survive tipping over onto its side in the
water. If they "landed" properly (legs deployed, descending at a slow speed
when they hit the water), I think one can make an argument for a fully
successful landing.

It really depends on how fast they hit the water.

~~~
grey-area
Sure, it depends, we'll have to wait and see what SpaceX decide to release
about it. It'll be nice to see video if they have some.

------
martythemaniak
This launch seemed to use a much steeper trajectory. Typically they go
downrange much faster than they gain altitude, but today they seemed to go up
faster than they were going downrange.

How does this affect the fuel efficiency of the launch? Is this a way to cut
down the horizontal velocity so they first stage can return more easily?

~~~
Zuph
It's a product of a higher target altitude (650km for Orbcomm vs. 330km for an
ISS resupply) and wanting to perform a single second-stage burn to achieve the
target orbit.

------
pjkundert
The second stage Falcon engine appears to have suffered some insulation
degradation and loss. It develops just above the bell, on the right-hand side
of the motor image in the video. After second stage shutdown, a vapor emission
is visible just above the site of the degradation (at the very end of the
video).

Was this a normal venting, or a non-catastrophic failure of the second stage
engine? Congratulations, SpaceX, on designing such a robust engine!

Video of launch:
[http://new.livestream.com/spacex/events/2980259/videos/56576...](http://new.livestream.com/spacex/events/2980259/videos/56576194)

~~~
lutorm
I believe those are normal vents. If you look at previous videos like
[http://youtu.be/RtDbDMRG3q8](http://youtu.be/RtDbDMRG3q8), there's are whole
frost "christmas trees" at several places around the base of the nozzle.

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cstross
Humph.

I'm choosing to take this personally!

(I was in Orlando at YAPC::NA in June, and drove up to the Cape _twice_ in
hope of seeing it launch. Scrubbed both times, and I got bitten to hell by
mosquitos before I discovered DEET -- yes, I'm British, we don't have flybown
tropical swamps.)

Ah well, maybe next time I visit ...

(Note that on the second visit they'd closed off the beach that enthusiasts
usually used to watch launches from. Much muttering among the rocket fans
present about SpaceX behaving very oddly -- this was the attempt when they
also cancelled the webcast. I wonder what was going on?)

------
teh_klev
Is this the re-usable launch vehicle, i.e. the one that re-enters the
atmosphere and lands itself upright?

~~~
cryptoz
Essentially yes. They won't be able to reuse this particular vehicle, but it
will return and hover over the ocean for them to retrieve. They'll recover it
and study the results to make the next one even better. Real reusability is
probably at least a year away.

------
K-Wall
I'll admit I do not regularly follow space launches but I am amazed at the
various places that they have installed video feeds. Seeing the first stage
drop off was incredible.

~~~
Kiro
What's a first stage drop off?

~~~
mikeyouse
AKA stage separation.

The first stage must provide a lot of thrust to get into lower gravity, so
it's quite heavy with fuel and has 9 engines. After the fuel in that stage is
expended, the rocket splits in two, dropping that first stage back to earth.
The top half of the rocket contains additional fuel and whatever payload the
rocket is delivering (including potentially an additional stage + engine) and
is powered with a single engine.

Here's an older video showing the separation:

[https://www.youtube.com/watch?v=p4lOJjKGoIY#t=193](https://www.youtube.com/watch?v=p4lOJjKGoIY#t=193)
(Goto: 3:15 if the link doesn't work)

The first stage that drops off is the one that SpaceX is attempting to
recapture. Historically, that stage just lands in the ocean and is either
scuttled or must be extensively cleaned and retrofit in order to fly again.
SpaceX figures if you leave a bit of extra fuel in the tanks, you can land it
vertically at the same site it took off from, and save yourself the time and
expense associated with cleaning and retrieving it.

This would be very valuable since the rocket engines are typically the most
expensive components of a launch, and the first stage has 9 such engines:

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

~~~
yock
It isn't higher gravity they're overcoming with the first stage, but rather
the much higher atmospheric pressure near the surface. Gravity in orbit is
almost identical to gravity at the surface.

~~~
mikeyouse
Pedantic and completely correct. H/T.

------
caval
Watching the camera feed of the launch around the 5 minute mark all I could
think was: if the rocket turned around now, it could probably land in New York
in another 5 minutes

~~~
jerf
On a ballistic trajectory, you can reach anywhere on Earth in 40 minutes or
less. I've seen cute little diagrams of the relevant times before, but I
wasn't able to quickly Google one up.

~~~
mikeash
Everyone who grew up during the Cold War knows this instinctively!

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alimoeeny
In case you want to watch it on youtube,
[https://www.youtube.com/watch?v=lbHnSu-
DLR4](https://www.youtube.com/watch?v=lbHnSu-DLR4)

------
mbell
Launch webcast: [https://www.youtube.com/watch?v=lbHnSu-
DLR4](https://www.youtube.com/watch?v=lbHnSu-DLR4)

------
dm2
I have nothing at stake in these launches but every one of them makes me
nervous, I almost can't watch them. At any moment, boom.

The launch video was beautiful though, the water vaporizing and forming a
could around the rocket is awesome, the inside view of the engine was amazing.

Can't wait to see the landing video!

What about the location of the landings? Have they been on target?

~~~
rrmm
They seem to be having consistent results (modulo the landings), so it's
almost safe to take a successful launch for granted (at least for people like
us who are just watching).

------
coder23
This is the fourth separate attempt at launching this mission. The first one
was more than a month ago. Their biggest problem are helium leaks.

Successful launch. We can expect better video footage of the first stage
landing.

~~~
skizm
So what happened on the first 3? Crashes?

~~~
apendleton
No, aborted before launch.

~~~
skizm
That makes sense. I feel like a crash would have been bigger news. Lucky I
caught the stream when it actually went up!

------
sgrove
"Speed 7.2km/s...and we have miko" \- what's miko referring to in this case?

~~~
cjbprime
Other commenter described it as MECO, googled that, found "Main Engine(s) Cut-
Off".

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joewalnes
Awesome! Are they going to repeat the launch for the west coast?

~~~
Crito
Their launch manifest
([http://www.spacex.com/missions](http://www.spacex.com/missions)) lists one
more launch from Vandenberg in 2014, and a few more in 2015. Eventually, if
everything goes according to their plans, they will be doing regular launches
from the west coast. _(Which site they use is determined by which sort of
orbit they are shooting for. They will launch from Vandenberg whenever
appropriate. Vandenberg is typically used for high-inclination /polar orbits,
or the rare retrograde orbit)_

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duncancarroll
Orbcomm, you say? This is all I can think of:
[http://upload.wikimedia.org/wikipedia/en/a/a9/U.F.Off_-
_The_...](http://upload.wikimedia.org/wikipedia/en/a/a9/U.F.Off_-
_The_Best_of_The_Orb_%28The_Orb_album_-_cover_art%29.jpg)

