
SpaceX’s Falcon Heavy rocket seems to be a hit with satellite companies - okket
https://arstechnica.com/science/2018/10/spacexs-falcon-heavy-rocket-seems-to-be-a-hit-with-satellite-companies/
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zaroth
What’s amazing to me is when companies do things like this that, for the
general public, make perfect sense only in retrospect.

Most seemly well-run companies are a total shit-show from the inside. Stupid
projects with features that no one wants, that engineering can’t build,
destined to never sell.

It’s just plain refreshing when you see a company firing on all cylinders
(sorry, couldn’t help myself) to the point where a shrewd move that helps
capture the market only becomes apparent, even to industry insiders, months or
years later.

It’s particularly satisfying when the CEO maps it all out in public years
ahead of time and then executes on that vision relentlessly for a decade,
despite the constant hate and doubt.

</Fanboy>

~~~
Brockenstein
I don't think I had an opinion beforehand or anything. I mean I was always
down with the idea. But I think the problem is that it's such a long process
to get from point A to B, and then the market for putting things into orbit is
pretty niche that most people just can't see the potential. And lot of people
are living from paycheck to paycheck aren't really planning years down the
road. It's completely out of their realm of experience or expertise in every
possible way. And they would never attempt it so that's get projected onto the
world as, "Anyone who attempts this is foolish."

Hindsight is 20/20 after all. And vision is only lauded in hindsight. Because
a vision that ends in failure gets a big "I told you so." from people who
usually have none.

~~~
WalterBright
> the market for putting things into orbit is pretty niche

It's only niche until the price comes down, like for computers, cars, air
travel, aluminum, coffee, etc.

~~~
tialaramex
Two things:

1\. Things can be niche because there just aren't that many people who want
them, rather than because you couldn't make them cheaply if there was demand.
A good quality Videodisc player for example costs far more now than it did at
the height of the format, because only weird retro collectors want one so
there's no reason to mass produce them. Videodisc players are niche.

2\. We're talking about literal space, it can actually fill up. Some orbits
are either so low that everything de-orbits soon enough anyway and needs
replacing, or so high that we'd never conceivably fill them, but in between
are plenty of useful orbits that are finite, so filling them up with more crap
doesn't make any sense even if you could do it for free.

~~~
zaroth
It’s not so much that there’s not enough room up there, but rather if any odd
piece of shit decides to disintegrate the debris field will make a large swath
of orbit uninhabitable until the debris falls back to Earth.

So even if getting up there gets cheap the things we put up there will still
need to be expensive.

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isostatic
There's a really good comment about why reigniting an engine after a long time
in space is difficult.

I hadn't even considered that the fuel will just be floating in the tank with
no forwards pressure

#ThingsKSPdoesn'tTeachYou

~~~
aw1621107
If you're interested in learning more about this kind of thing, you want to
look stuff related to "ullage".

Fun fact: it doesn't actually take that much time without forwards
acceleration for ullage to become an issue. For example, the Saturn V included
solid-fuel rockets on the interstage between the first and second stages to
provide enough forwards acceleration for the second stage engines to ignite,
even though the gap between the first stage engines shutting down and the
second stage engines igniting wasn't more than several seconds [0, page 14].
You can see the exhaust from those motors on the outside of this video of the
Apollo 4 first stage separation [1].

Another fun fact: instead of using smaller motors to provide acceleration
between stages, (some?) Soviet rockets ignited upper-stage engines _while the
lower-stage engines were still firing_ ("hot-staging"). This is why some
soviet rockets had a lattice (or lattices) between stages instead of solid
metal.

Yet another fun fact: it doesn't take much acceleration to sufficiently settle
the fuel for ignition. The Saturn V's S-IVB stage used its equivalent of its
RCS system, which is normally used for attitude control, to settle its fuel
prior to firing for trans-lunar injection.

If you're interested in installing KSP mods, RealFuels includes ullage
simulation, so you'll need to have some method of providing acceleration to
get larger rocket motors to ignite reliably.

[0]:
[http://web.mit.edu/digitalapollo/Documents/Chapter5/saturnas...](http://web.mit.edu/digitalapollo/Documents/Chapter5/saturnas501.pdf)
[1]: [https://youtu.be/iJIY4n5oXjc?t=8](https://youtu.be/iJIY4n5oXjc?t=8)

Edit: Fix description of hot-staging for Soviet rockets. Some Soviet rockets
hot-staged their third stage and not their second stage, making the
description incorrect.

~~~
outworlder
One thing I don't know if it is correct is that, on KSP, I've managed to deal
with ullage using the overpowered reaction wheels (essentially using
centripetal force). Pretty sure that would not work properly in real life,
with real materials...

~~~
aw1621107
It's physically possible, but it almost certainly wouldn't be practical. The
mass needed for a reaction wheel of the right size would probably make it too
expensive, never mind the control and mechanical issues of dealing with an
accelerating spinning rocket.

~~~
outworlder
Yeah, I don't think a rocket would like this lateral acceleration at all, even
if we replaced the reaction wheels with something less far-fetched.

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jonesdc
Anyone else enjoy the PDF-like presentation of the webpage? This design is so
clean. I initially thought OP submitted a document.

~~~
sand500
> This design is so clean.

Does that include the giant video ad at the top?
[https://imgur.com/a/4QvQO3W](https://imgur.com/a/4QvQO3W)

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ChuckMcM
That is a pretty big advantage if you save all of that fuel on the satellite.
It translates directly into extra years on station and so longer payoff
period.

~~~
greglindahl
Sure, if you have already built the satellite, and it shares fuel between
orbit raising and station keeping, it can be a big win. ULA convinced the US
to do that with GOES-16, recently.

But if you're designing from scratch, building a bigger satellite and staging
earlier gets more mass to GEO. That's called a "subsync" orbit and SpaceX has
talked 2 customers into doing that with 3 satellites so far: Telstar 19V,
Telstar 18V, and Hispasat 30W-6.

[https://www.reddit.com/r/spacex/wiki/launches/gto_performanc...](https://www.reddit.com/r/spacex/wiki/launches/gto_performance)

In these latter 3 examples, the customer saved ~ $30mm on the launch by
staying within the reusable F9 mass limit.

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formatkaka
Elon Musk's biography is no less than a thriller :)

Short Story :

He once took Tesla Model S (not fully developed) to his home from tesla HQ.
The next morning, he came back with more 40 changes to be made. And yes, he
remembered all those changes after more than 12+ hrs.

