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1458: Small Moon

Posted: Wed Dec 10, 2014 6:22 am UTC
by ricree
Image

Title text:GENERAL JAN DODONNA: An analysis of the plans provided by Princess Leia has reinvigorated the arguments of the 'artificial moonlet' and 'rogue planet-station' camps. I fear this question is fracturing the Rebellion.



If it's orbiting another planet, does that make it an exo-artificial moonlet?

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 6:29 am UTC
by Steve the Pocket
By what standards is anything "too big" to be a space station? Especially in a universe that also contains an entire planet covered in city.

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 6:31 am UTC
by rhomboidal
I knew the whole planet-destroying super-laser was just a ruse. The Empire's strategy to subtly undermine the Rebel Alliance from within using terminological hairsplitting is insidious, indeed.

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 6:33 am UTC
by Djehutynakht
Behold!

It is a Satellite.

There.

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 7:14 am UTC
by Klear
Djehutynakht wrote:Behold!

It is a Satellite.

There.


Or better yet, it's a thing.

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 7:44 am UTC
by Diadem
Klear wrote:
Djehutynakht wrote:Behold!

It is a Satellite.

There.


Or better yet, it's a thing.

That's just cruel! They have feelings too you know! Are you denying the Death Star personhood?

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 7:46 am UTC
by Eternal Density
Yessss, your arguments, they feeed me!

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 7:47 am UTC
by karhell
Diadem wrote:
Klear wrote:
Djehutynakht wrote:Behold!

It is a Satellite.

There.


Or better yet, it's a thing.

That's just cruel! They have feelings too you know! Are you denying the Death Star personhood?

It's a complex multicultural and ethnically diverse entity. Happy now ? ^^

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 8:03 am UTC
by eviloatmeal
Completion of the Def. Star is imminent! Soon, those pesky Jedi will plunge the entire world into argument about how to classify our voluminous stationoid!

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 8:17 am UTC
by Pfhorrest
People are things too.

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 9:49 am UTC
by ps.02
A Dwarf-moon, is it? So I suppose the Imperial battle cry would be "Moons of the Dwarves! The Dwarves are upon you!"

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 11:10 am UTC
by orthogon
I guess the Death Star would have noticeable gravity, certainly more than Comet 67P. Based on the diameter of 160km, I make it about 0.01N/kg or 1/1000 of Earth's surface gravity. I assumed that the density was around 0.5kg/m3 based on the mass and pressurised volume of the International Space Station. (Incidentally, NASA gives the measurements in "US Customary units", with the SI units in brackets1 afterwards).

1which they would no doubt call "parentheses".

[Edit: subscript on m3]

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 11:56 am UTC
by Feldmarshall
I'd like to point out, that Death Star can clear orbit, ANY orbit, of other bodies.

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 12:00 pm UTC
by Plasma Mongoose
The asteroid 243 Ida which has an average diameter of 31.4km, the remarkable thing is that it has a 1.4km diameter moon called Dactyl which orbits around Ida every 20 hours.

If a 1.4km rock can be classed as a moon, then the Death Star can easily be called one too as long as it is orbiting a larger object.

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 1:54 pm UTC
by Murderbot
Djehutynakht wrote:Behold!

It is a Satellite.

There.

A satellite is an objects that orbits a planet. The Death Star moves from one star system to another at superluminal speeds, making it a starship. Officers aboard it refer to it as a "battle station", if I'm not mistaken, which is close to what Carl Sagan called planned spaceborne anti ballistic missile lasers (The same technology that puts an astronomer and a telescope in Earth orbit can also put up a laser “battle station”.).

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 2:04 pm UTC
by wumpus
orthogon wrote:I guess the Death Star would have noticeable gravity, certainly more than Comet 67P. Based on the diameter of 160km, ]


Since wiki lists Deimos as having a diameter of 12.6km, you would have to reclassify most of the known moons at the time. A better question is "so where is the planet it is orbiting"? I don't recall a planet or more importantly a blazing star nearby.

Even if the Death Star is under 160km, I'm pretty sure it is at least 12.6km based on the trench run.

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 2:12 pm UTC
by Jackpot777
Diadem wrote:
Klear wrote:
Djehutynakht wrote:Behold!

It is a Satellite.

There.


Or better yet, it's a thing.

That's just cruel! They have feelings too you know! Are you denying the Death Star personhood?


As DeathStarKin, I agree with this sentiment and will use fear to keep you in line. Fear of me.

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 2:48 pm UTC
by orthogon
It just occurred to me that "small moon" could almost be synonymous with "plumber's bum".

Pseudo-edit: on second thoughts, plumber's bum normally isn't so much a small moon as a large moon in an early "phase".

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 3:18 pm UTC
by Whizbang
That's no moon, that's a heavenly body.

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 3:45 pm UTC
by cellocgw
My my my.... looks like Randall's having another bad-Pluto day :mrgreen:

Whizbang wrote:That's no moon, that's a heavenly body.

Whizbang's been looking a magazine covers of Kardashian!

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 3:52 pm UTC
by AEB
wumpus wrote:A better question is "so where is the planet it is orbiting"? I don't recall a planet or more importantly a blazing star nearby.


You mean Alderaan? They blew it up.


As for the NASA link posted above, I don't get this quote:
The entire 55-foot robot arm assembly is capable of lifting 220,000 pounds, which is the weight of a space shuttle orbiter.


What does it mean to "lift" something outside the ISS? What does "weight" mean in micro-gravity? I assume they meant mass, but even then...

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 3:59 pm UTC
by Moose Anus
orthogon wrote:It just occurred to me that "small moon" could almost be synonymous with "plumber's bum".

Pseudo-edit: on second thoughts, plumber's bum normally isn't so much a small moon as a large moon in an early "phase".
It so happens that I'm a plumber and my bum is waxing gibbous.

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 6:16 pm UTC
by Pfhorrest
We don't need to hear about your waxy monkey-bum.

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 7:21 pm UTC
by slinches
AEB wrote:
wumpus wrote:A better question is "so where is the planet it is orbiting"? I don't recall a planet or more importantly a blazing star nearby.


You mean Alderaan? They blew it up.

Wasn't it orbiting (or at least performing a gravitational assist maneuver around) a gas giant in the Alderaan system?

AEB wrote:As for the NASA link posted above, I don't get this quote:

The entire 55-foot robot arm assembly is capable of lifting 220,000 pounds, which is the weight of a space shuttle orbiter.

There's an implied "in normal earth gravity (aka 1g)" appended to these sorts of statements. Although, it would be helpful if they actually included it once in a while to show they know the difference between weight and mass.

If that's still not clear, here's a fixed version: :mrgreen:
The entire 660-inch robot arm assembly is capable of lifting 570 slinches (lbf-s^2/in), which is the mass of a space shuttle orbiter.

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 7:32 pm UTC
by RedwoodRhiadra
wumpus wrote:Even if the Death Star is under 160km, I'm pretty sure it is at least 12.6km based on the trench run.


IIRC, the first Death Star was 120km in diameter, the second Death Star was 160km. (I can't remember my source offhand - it may have been one of the sourcebooks for the original Star Wars RPG by West End Games.)

Besides Phobos and Deimos, all of the gas giants have quite a number of moons which are less than 120km diameter.

slinches wrote:Wasn't it orbiting (or at least performing a gravitational assist maneuver around) a gas giant in the Alderaan system?


That was Yavin (the gas giant) during the trench run (the Rebel base being on one of Yavin's moons). Orbiting may simply have been the most efficient way to maneuver around the planet to get a clear shot at the moon. (Presumably even the superlaser isn't powerful enough to simply blow up a gas giant!)

They don't seem to orbit anything in the Alderaan system.

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 7:38 pm UTC
by orthogon
Speaking of slinches, is anyone else bothered by an inability to imagine a square second? I mean, I get that acceleration is metres per second per second, but it feels like there should be an intuitive meaning to metres per square second too. If our universe had two or more timeline dimensions, a square second would be a thing.

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 7:56 pm UTC
by da Doctah
Death Star's not really a space station, either, not even a really big space station.

Seems the Empire used the same reasoning the auto manufacturers use to get something classed as a "truck" or "utility vehicle" or some other made-up category instead of "car" so it doesn't futz up the figures for average fuel efficiency.

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 8:11 pm UTC
by Quizatzhaderac
AEB wrote:
wumpus wrote:A better question is "so where is the planet it is orbiting"? I don't recall a planet or more importantly a blazing star nearby.


You mean Alderaan? They blew it up.
Right, blowing up it's planet means it's no longer a moon or satellite since it's not orbiting anything anymore. Even if Han assumes it's orbiting the star, that would make it an asteroid since the obit is predominately unbound Alderaan pieces and it's not in hydrostatic equilibrium.

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 8:11 pm UTC
by Coyoty
cellocgw wrote:My my my.... looks like Randall's having another bad-Pluto day :mrgreen:

Whizbang wrote:That's no moon, that's a heavenly body.

Whizbang's been looking a magazine covers of Kardashian!


The magazine she covers is Paper, so is it a Paper moon?

BTW, she should cover herself. Her moon looks like it's on ass steroids and artificial. Which is what we should be calling the Death Star, an artificial asteroid.

"That's no moon... It's a Kardashian!"

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 9:10 pm UTC
by rmsgrey
One thing I hope we can all agree on - despite the grandiose appellation attached to it by Rebel propagandists, one thing it is most definitely not is any sort of star.

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 9:40 pm UTC
by AEB
slinches wrote:
AEB wrote:As for the NASA link posted above, I don't get this quote:

The entire 55-foot robot arm assembly is capable of lifting 220,000 pounds, which is the weight of a space shuttle orbiter.

There's an implied "in normal earth gravity (aka 1g)" appended to these sorts of statements. Although, it would be helpful if they actually included it once in a while to show they know the difference between weight and mass.

If that's still not clear, here's a fixed version: :mrgreen:
The entire 660-inch robot arm assembly is capable of lifting 570 slinches (lbf-s^2/in), which is the mass of a space shuttle orbiter.


Okay --- but what does it mean to lift something that is already off the ground (considering that anything the arm is "lifting" is already in space)? Is the lifting directional? Is it still "lifting" if the arm moves an object closer to the earth? Even ignoring the units and the whole "mass" vs "weight" thing, the phrase still doesn't really make much sense... unless what they meant was, if the arm were on earth, it could lift a space shuttle off the tarmac... which is pretty cool.

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 10:16 pm UTC
by Quizatzhaderac
The original text said "220,000 pounds", which is a unit of force, not mass. The arm can exert 220,000 pounds of force, which is enough to lift the space shuttle orbiter, on Earth.

In space that just means it's capable of moving the orbiter at 9.8 m/s^2.

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 10:35 pm UTC
by slinches
Lifting is possible in space as long as your reference coordinate system has a vector that's chosen to be considered upward. In the case of the shuttle that would be the way the tail is pointing (roughly). But now that I think about it, they probably meant that the arm was designed to accelerate something of equal mass to the shuttle to some minimum speed in a set amount of time while in a microgravity environment. Although, that doesn't sound as impressive.

Ironically, if the arm was used to lift the shuttle on earth the stress on it would be astronomical.

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 10:39 pm UTC
by chenille
Coyoty wrote:"That's no moon... It's a Kardashian!"

Only two letters away from a Star Wars and Star Trek crossover.

Re: 1458: Small Moon

Posted: Wed Dec 10, 2014 10:59 pm UTC
by Sir Lunch-a-lot
Quizatzhaderac wrote:The original text said "220,000 pounds", which is a unit of force, not mass. The arm can exert 220,000 pounds of force, which is enough to lift the space shuttle orbiter, on Earth.

In space that just means it's capable of moving the orbiter at 9.8 m/s^2.


I am pretty sure that the Canada Arm 2 could not lift a space-shuttle on earth. I seem to recall around the time that it was launched there was a segment on Daily Planet (or its precursor - a show on the Canadian version of Discovery Channel) discussing the Arm, and I believe they were saying that the arm itself was so massive that it couldn't even lift itself under earth Gravity - severely limiting the testing they could do on it prior to sending it to the ISS.

Re: 1458: Small Moon

Posted: Thu Dec 11, 2014 12:12 am UTC
by HES
Murderbot wrote:A satellite is an objects that orbits a planet. The Death Star moves from one star system to another at superluminal speeds, making it a starship. Officers aboard it refer to it as a "battle station", if I'm not mistaken, which is close to what Carl Sagan called planned spaceborne anti ballistic missile lasers (The same technology that puts an astronomer and a telescope in Earth orbit can also put up a laser “battle station”.).

Of course, the battle stations you're describing would be satellites.

Re: 1458: Small Moon

Posted: Thu Dec 11, 2014 4:18 am UTC
by dtilque
eviloatmeal wrote:Completion of the Def. Star is imminent! Soon, those pesky Jedi will plunge the entire world into argument about how to classify our voluminous stationoid!

And it's going to turn a deaf ear to those arguments.


In space, no one can hear them anyway.

Re: 1458: Small Moon

Posted: Thu Dec 11, 2014 8:46 am UTC
by Neil_Boekend
slinches wrote:
AEB wrote:
wumpus wrote:A better question is "so where is the planet it is orbiting"? I don't recall a planet or more importantly a blazing star nearby.


You mean Alderaan? They blew it up.

Wasn't it orbiting (or at least performing a gravitational assist maneuver around) a gas giant in the Alderaan system?

AEB wrote:As for the NASA link posted above, I don't get this quote:

The entire 55-foot robot arm assembly is capable of lifting 220,000 pounds, which is the weight of a space shuttle orbiter.

There's an implied "in normal earth gravity (aka 1g)" appended to these sorts of statements. Although, it would be helpful if they actually included it once in a while to show they know the difference between weight and mass.

What bugs me about the statement is that mass doesn't matter in that way. In friction-less environments you can move anything given an adequate anchoring point. Heavy things just take more time with the same force than light things.
Thus a 220,000 kg object could be moved too, It just takes approximately twice the time (and some additional programming to prevent jerk forces by allowing for approx. twice the time)

Re: 1458: Small Moon

Posted: Thu Dec 11, 2014 9:23 am UTC
by orthogon
Yeah, I was always impressed that I, a weedy* 17 year-old at the time, could move a 18 tonne narrowboat around by pulling on a rope with my bare hands. The issue isn't so much getting it going as stopping it once it's moving, on account of how ropes aren't very good in compression. I imagine making sure you start pushing at the right time is a big problem when hauling stuff around in space.

*I'm being modest here. Actually I was pretty ripped by the end of that summer.

Re: 1458: Small Moon

Posted: Thu Dec 11, 2014 2:33 pm UTC
by niky
wumpus wrote:
orthogon wrote:Even if the Death Star is under 160km, I'm pretty sure it is at least 12.6km based on the trench run.


Abnormally long run sequences on film: Ref: Fast and Furious 6. /Ref.

Of course, Luke didn't have to downshift twenty or thirty times...