
SpaceX successfully lands its sixth Falcon 9 rocket after launch - molecule
http://www.theverge.com/2016/8/14/12467632/spacex-falcon-9-jcsat-16-drone-ship-landing-success
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davej
> SpaceX’s president, Gwynne Shotwell, estimates that reusing these landed
> Falcon 9 vehicles will lead to a 30 percent reduction in launch costs,
> according to Space News.

Surely it will be more than a 30% reduction once they make the rocket
refactoring process more efficient? I've heard Elon say that the savings would
be an order of magnitude given how low the cost of fuel is relative to
everything else on the rocket.

I know Elon is famously optimistic and Gwynne is probably dampening
expectations on purpose but 30% doesn't seem very impressive. Is Gwynne just
playing down the cost savings or is she likely to be accurate, even in the
medium term (3-5 years)?

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agildehaus
It doesn't make much business sense to pass along ALL the efficiency savings
directly to your customers.

30% reduction in launch costs will be hugely welcomed and SpaceX will be able
to do lots with the additional revenue.

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davej
Perhaps I misunderstood what Gwynne was saying. I thought that "launch costs"
would be the cost of launching a rocket for SpaceX, rather than the price that
they set for customers.

Perhaps your correct though, the quote is a bit ambiguous.

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codesterling
"It's saving 90% in launch costs, but we're only passing 30% of the savings
along to the customer" doesn't sound very good in a press release.

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richardw
What could SpaceX have learned about landing a rocket on a boat resting on
waves?

It seems like the craziest idea. I would have said "No chance. Land it on
land, like the word says." but they've managed the risks down to where it's
not surprising that they've landed yet another one. Some special magic has
gone into that and I can't even imagine what issues they've had to solve.

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ygra
They mentioned on the live stream that the landing _point_ doesn't really
change the difficulty. It doesn't matter whether they land on water or on
land, for the most part. What makes the landings difficult is how much
propellant is left in the first stage. There's more of it left after a LEO
launch, so they can do a longer landing burn and during that have more
opportunity to correct, e.g. for winds. With the GTO launches there's only
very little left, so the landing burn is shorter, which also stresses the
vehicle more. This time they were happy to actually do a one-engine landing
burn as opposed to three engines like they did with the drone ship landings so
far (I think it has always been three engines at first and then one engine for
the very last bit for drone ship landings until now).

They've also noted numerous times that waves don't really matter much to the
landing.

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brianwawok
So can they add 5% more propellant to the rocket, or perhaps lower the weight
of the rocket a bit so for the same propellant - more is left when it lands?

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ygra
Propellant tanks are full at liftoff, so no, there's no way of adding more.
And there's also no room to save weight either, considering that every bit of
saved mass is more payload capacity to orbit. Two features of the Falcon 9
Full-Thrust upgrade increased propellant limits, though: One was bigger tanks,
but I think they said they're now at a height limit for various reasons
(structural integrity of an empty rocket stage is usually abysmal, for
example, and you want to land it upright and empty). The other was
superchilling the propellants, which made them a bit denser, thereby fitting
more.

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journeeman
I know it's too early but, I'm already kinda getting used to this.

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_audakel
key point - "spacex has yet to actually reuse any of its vehicles"

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ChuckMcM
True, interesting collection of Merlin engines they have. If nothing else
their spare parts cache is huuuuge. :-)

Can't wait to see what they launch with the refurbed boosters.

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toomuchtodo
Supposedly a reused booster will fly in the next 3 months; they're still
haggling on price with the customer.

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phire
I wouldn't be surprised if they are haggling with the insurance company on the
risks of reusing a booster.

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toomuchtodo
It's possible. Only this summer did insurance rates on the Falcon 9 come down
to those on the Ariane 5. SpaceX will have to provide extensive data
(especially from the static fire in McGregor) to bolster reliability claims on
a landed booster.

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Animats
2017 will be the big year for Space-X. First Falcon Heavy flight, and first
crewed Dragon flight.

~~~
creshal
Every year since 2013 was the year of the first Falcon Heavy flight. Maybe
_this_ time.

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Symmetry
They keep re-designing the Falcon 9 and adding new features so it's not really
surprising. Those poor engineers working on it, "What do you mean you're
increasing the Falcon thrust _again_. Now we have to reinforce the connectors
even more." The capacity of a Falcon 9 has gone from 10 tons to orbit up to
23.

~~~
creshal
Yes, and they're not done yet. I think the upper stage is going to get another
thrust improvement with the next flight or so.

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patman81
Still amazing to watch! Can't wait to see the Falcon Heavy liftoff, followed
by two simultaneous first stage landings.

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hanoz
My daughter and I saw a couple of strange flashes in the sky while out looking
for Perseids last night. We're in the UK and the flashes were in Cassiopeia in
the North Eastern sky at about 10pm BST, is possible they could have been from
this rocket?

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david-given
Could it have been an Iridium flare? The timing sort of matches up.

[http://www.heavens-
above.com/IridiumFlares.aspx?lat=53.1204&...](http://www.heavens-
above.com/IridiumFlares.aspx?lat=53.1204&lng=-2.2852&loc=Unspecified&alt=95&tz=GMT)

~~~
hanoz
I did wonder about that but there were two or three flashes in quick
succession. It was spookily close to matching up with that 22:29 flare
prediction in Cassiopeia, but it was at least half and hour before that.

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geuis
Question about the second stages: Are these left in orbit or are they
deorbited?

~~~
walrus01
Depends on the launch. There is no remaining fuel in a second stage for any
Delta v to lower its orbit into the atmosphere in most launches. A launch to
GTO at 350 x 36,000 km will eventually decay. In some satellite launches there
is a third stage (like a fregat, but not the same thing) which performs the
final circularization of the orbit. In others the satellite itself does this.
In a launch to an MEO orbit like 1500x1500 km the 2nd stage is going to stay
up there pretty much forever as dead debris.

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ygra
SpaceX doesn't do GEO launches as far as I know, only GTO. I don't know
whether from a lack of capability or whether they're not allowed/certified for
that, though. I guess an expendable F9 should easily be able to get to GEO.

~~~
toomuchtodo
SpaceX does GEO since December 2013.

[http://www.spacex.com/press/2013/12/03/spacex-
successfully-c...](http://www.spacex.com/press/2013/12/03/spacex-successfully-
completes-first-mission-geostationary-transfer-orbit)

~~~
InclinedPlane
SpaceX doesn't do direct GEO insertion, only boosting to a Geostationary
Transfer Orbit (GTO) which is the norm for satellites headed to GEO. The
satellite itself does the circularization, which isn't hugely costly fuel wise
but requires a stage that can restart after coasting all the way to GEO
altitude (several days), which SpaceX currently lacks (the 2nd stage runs on
batteries).

~~~
walrus01
Yes, exactly this. GEO requires an engine that is low kN thrust but can be
restarted many times. The Wikipedia page for the Russian fregat which is
commonly used as a 3rd or 4h stage for their launches is a good example of
such hardware. If you're patient you can even circularize a GTO with ion
engines, which has been done on some partially-failed telecom satellite
launches.

~~~
the8472
It has also been done by design instead of a fallback.

[http://www.boeing.com/features/2015/01/bds-702sp-01-26-15.pa...](http://www.boeing.com/features/2015/01/bds-702sp-01-26-15.page)

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justrossthings
Looking forward to this not even being news in the future. Thank you Elon

