Interstellar

[Moss]

I may be late to the party on this one, but having seen this movie I'm convinced me that there should science fiction/ adventure gameplay support in the base game, even if it never becomes stock.

[RogueMason]

I finally got to see it yesterday with a friend, and I loved it. I don't care if there were minor scientific errors (things like that don't bug me in films), Interstellar is a damn good film!

If you'll excuse me, I've got to make a Ranger-esque ship in KSP now...

[InfinityArch]

So apparently there's some hard facts given about the Gargantua system in "The Science of Interstellar"; Gargantua itself is a supermassive black hole, weighing in at approximately 100 million solar masses, rotating with an angular velocity approaching the speed of light. While the required math to figure this out is not something I'm confident with, it's been determined that there do exist stable orbits around such an object where one would experience time dilation on par with what is seen in the movie. Whether or not it's at all plausible for a planet avoid being torn apart in such an orbit is another question, but IIRC, Kip Thorne seems to think the second planet they visit was the least plausible because the material strength of ice wouldn't allow the formation of the frozen clouds.

The bigger problem, which Scott Manley points out in his review, is that at first glance, the required delta v's would be absolutely absurd. After derping around with the equations for gravitational time dilation for a while, assuming Miller's World has a mostly circular orbit, it would orbit about at a distance about 67 million kilometers greater than the semimajor axis of Mars, or 295,392,295 km. Using basic equations for orbital velocities, I'm coming up with an orbital velocity of 0.707106782 c (211,985,280 m/s) for Miller's World, where is definitely fast enough for relativistic effects to become "significant" though from what I recall, at such speeds the gravitational time dilation would still dwarf the speed induced dilation. Frame dragging from the black holes rotation probably comes into play as well, but I haven't even the foggiest idea how to estimate that.

Now, it's stated that Mann's world doesn't experience significant time dilation from proximity to the black hole, and, taking that statement fairly liberally (every hour on Mann's world=1.5 hours on Earth) and assuming a circular orbit, Mann's world would orbit at around 527,486,241 kilometers above the singularity, which is between the orbits of Mars and Jupiter. At this distance the orbital velocity of Mann's world would be around 158,635,258 m/s, or 0.529150263 c.

I have no idea how to calculate the minimum delta v to transfer between two orbits, but based on the delta v costs to transfer to mars, it's similar to the difference between the two bodies' mean orbital velocities, which in this case is 211,985,280 m/s-158,635,258 m/s, or about 53,000 Km/s, which corresponds to 0.177956518 c. On the plus side, because the hypothetical orbital period of Mann's world would be around 6 hours, and Miller's world significantly less, transfer windows would appear all the time. On the less positive side, I suspect they'd be extremely short.

Now, the Delta-V requirements for the Endurance mission (though not the design, which doesn't appear to have that great of a mass ratio) would be feasible with beamed core antimatter (exhaust velocity is something like 0.3 c), and maybe with extremely efficient nuclear fusion based propulsion if you squint at it the right way.

That begs several questions however:

A. If they have access to that kind of propulsion, wouldn't it be trivial to evacuate Earth even without discovering the secrets of gravity manipulation?

B. Given that the mission is under significant time pressure, why wouldn't they opt for a more aggressive outbound flight? Using a 1g Brachistochrone trajectory, it would take about 17 days to reach Saturn and about 10 million km/s of delta V, which could be accommodated for in the delta V budget by some extra drop tanks.

Edited November 20, 2014 by InfinityArch

[InfinityArch]

Now, even though I'm probably off by a fairly sizable margin for a variety of regions, I went back and redid the numbers with even more liberal interpretations of the dialogue.

For a model which assumes 1 hour on Mann's world is a day of Earth time, then we come up with an orbital velocity of 211,801,185 m/s, and a difference of a mere 184.095 Km/s. That's actually well within the realm of plausibility for electromagnetic propulsion systems. Of course, in that version, Mann's world has an SMA of 295,906.021 Km, which I have a sneaking suspicion might be too close to Miller's world for their orbits to be stable. Going down to 1 hour=12 hours on Earth, we're looking at a velocity difference of around 740 km/s, which is beyond the exhaust velocity of VASMIR (and mass ratios become unreasonably large after that point from what I know), but well within the reasonable limits of a helium-3/deuterium fusion based propulsion system (maximum exhaust velocity given as 7,840 km/s by Atomic Rockets).

As far as the Ranger to Miller's world and back thing goes, I really don't have time to go through the math for that (and I've have to make even more assumptions that would probably f' up the final result even more), but I suspect you'd come up with something low enough that a fusion based nuclear thermal rocket could manage it.

Edited November 20, 2014 by InfinityArch

[AndrewBCrisp]

That begs several questions however:

A. If they have access to that kind of propulsion, wouldn't it be trivial to evacuate Earth even without discovering the secrets of gravity manipulation?

B. Given that the mission is under significant time pressure, why wouldn't they opt for a more aggressive outbound flight? Using a 1g Brachistochrone trajectory, it would take about 17 days to reach Saturn and about 10 million km/s of delta V, which could be accommodated for in the delta V budget by some extra drop tanks.

A) I believe the big stumbling block that made gravity manipulation preferable to building more rockets was logistical and social, rather than engineering. There were plenty of clues in the film that

a) Humanity had experienced a minor or major population crash prior to the events of the film,

The surviving humans had locked themselves into a cycle of self-denial, insisting that so long as they have enough farmers, they'll get through these Tough Times okay, and

c) Until the Tough Times end, any extraneous spending - like on more spacecraft - would be met with a massive public blowback, possibly including angry mobs ready and willing to kill everyone in the NASA bunker.

There was no real way for NASA to get public support for a major rocket-building program without revealing the ugly truth that the Blight is winning, and that our time on Earth can be measured in decades if not years. Either the public would not believe them, and send in the angry mobs to destroy the bunker; or the public would believe them, and in a panic destroy the bunker trying to get aboard the rockets already built. Plan A - the mass evacuation of Earth - needed to be presented with everything already in place, and all the public needing to do was pack their things and enter the stations.

Plus, given the near-desperate timescale of the evacuation, building the stations on Earth and lofting them into space via gravity manipulation saves precious time. A conventional evacuation plan would need time to build all the needed launch facilities, time to build the rockets, time to build the space-based station-construction facilities, and then time to build the stations themselves. Gravity manipulation neatly cuts out the first three phases of the conventional plan.

I suspect that the secrecy of the project - and the need for time to solve the gravity manipulation problem - were the major reasons for the 2 years to Saturn. Every launch from the Earth risks detection by people not sympathetic to the existence of NASA, so keeping the number of launches to a minimum helps. Those extra drop-tanks might save time for the mission, but also risk discovery, meaning Endurance might complete its mission and return to find the bunker destroyed by the people left behind.

Plus, the gravity manipulation project was still at the theoretical stage when the Endurance launched. Even assuming a Manhattan-Project approach, going from equations to working gravity drives might take years. It was a tremendous act of faith on the part of NASA to start building their first station before the gravity problem was solved.

[FishInferno]

Cooper: "set humor to 75%"

Robot: 'Ten seconds to self-destruct..."

Cooper: "Make that 60%"

I loved the scene where the kid hits a baseball straight up and knocks out a window on the "roof"

[SpaceXray]

Cooper: "set humor to 75%"

Robot: 'Ten seconds to self-destruct..."

Cooper: "Make that 60%"

I loved the scene where the kid hits a baseball straight up and knocks out a window on the "roof"

TARS and CASE were the best robots ever.

[FishInferno]

Ok, so I asked this before, and didn't get a response. Is there actually proof that the rocket was a Saturn V? In the scenes where it shows its engines in the launch chamber, there appears to be only 3 engines.

[White Owl]

I thought it was something like a SLS without the SRBs.

[Airlock]

Ok, so I asked this before, and didn't get a response. Is there actually proof that the rocket was a Saturn V? In the scenes where it shows its engines in the launch chamber, there appears to be only 3 engines.

See here: http://endurance.interstellarmovie.net/

The Ranger shuttles were launched "belly-to-belly" on top of a " large multi-stage booster" - most likely to be a modified Saturn V.

Did some searching and found this - apparently, an unused template mission patch for the film -

EDIT: Woops, actually it's from the same site: http://patchcreator.interstellarmovie.net/

Edited November 25, 2014 by Airlock

[SpaceXray]

Looks a lot like the Saturn V. And yes, the 2 Rangers were launched belly-to-belly on top, which is why they did a launch in the first place instead of taking off with the Rangers one by one and using up the special and expensive fuel the Rangers used.

[lajoswinkler]

It isn't Saturn V.

That's the wallpaper I've seen in cinema. It looks like an Atlas V to me.

[SpaceXray]

It isn't Saturn V.

http://www.wallpaperup.com/uploads/wallpapers/2014/06/10/367002/c28cfc439ce01f52d156da54729013a0.jpg

That's the wallpaper I've seen in cinema. It looks like an Atlas V to me.

http://www.thespacereview.com/archive/2042a.jpg

Never seen that poster on official sources. Must be fake.

And an Atlas V can't launch 2 Rangers, only a small satellite or probe.

[Kryten]

Never seen that poster on official sources. Must be fake.

Posters are often knocked together by local distributors, and might end up not having anything to do with the actual movie. As a pretty infamous example, here's the polish poster for 'Weekend at Bernies';

And an Atlas V can't launch 2 Rangers, only a small satellite or probe.

Is this your first time seeing a science fiction film? Next you'll tell the shuttle couldn't reach an NEO and didn't carry a gatling gun...

[Helix935]

Cooper: "set humor to 75%"

Robot: 'Ten seconds to self-destruct..."

Cooper: "Make that 60%"

I loved the scene where the kid hits a baseball straight up and knocks out a window on the "roof"

loved that scene too although during that scene, was i the only one that noticed that the o'neill cylinder that they were on isn't really wide enough to sustain a earth like gravity with a reasonable amount of rotation like say about 1 to 2 rotations a minute for a truly reasonable sized cylinder. Although considering they were doing research artificial gravity, they probably already solved problem and did not need rotation but wanted to make sure space with in the cylinder was used efficiently...

[SpaceXray]

loved that scene too although during that scene, was i the only one that noticed that the o'neill cylinder that they were on isn't really wide enough to sustain a earth like gravity with a reasonable amount of rotation like say about 1 to 2 rotations a minute for a truly reasonable sized cylinder. Although considering they were doing research artificial gravity, they probably already solved problem and did not need rotation but wanted to make sure space with in the cylinder was used efficiently...

The cylinder was rotaing at around 4-5 rpm, we see that during the final shot of Cooper preparing to fly away from the station in the Ranger.

[xtoro]

Haven't seen this yet but I plan to. I'm just hoping that KSP hasn't ruined yet another scifi space movie for me lol "You can't do that!" "It doesn't work like that!" "That wouldn't work to get a rendez-vous..." And so on...

[TythosEternal]

It isn't Saturn V.

That's the wallpaper I've seen in cinema. It looks like an Atlas V to me.

That is indeed an Atlas V in the poster, and was definitely not what was in the film. Nonetheless, that poster (whether it's fake or independently-produced) is downright gorgeous. Better than most of the real ones, in fact (IMHO, of course).

[problemecium]

I hope I'm not too egregiously late to the party, but I just saw the film today.

Overall I think it was good, though definitely not Nolan's best film. I ended up paying very little attention to the orbital physics (fortunately), so those didn't end up irritating me as much as they might have. However.

I'll be the millionth person to rant that the scene where he goes into Gargantua is a bunch of hooey. I did actually sort of call that he'd end up being the "ghost" / "Them" early in the film, so by the time he went in I basically knew what was coming (It's full of stars!). But I hope this movie doesn't go giving anyone any bright ideas about jumping into black holes because they glossed over what we do know (as well as we can hope anyway) about what's inside that event horizon.

First things first, it's kinda sad that they didn't take the opportunity to show what it'd look like to um... I forgot his name. McConaughey. To him as he went in. We know already that the event horison is only black from outside - from inside, you can't really tell when you've gone past it at first, until everything starts going all blue-shifted and yadda yadda yadda. That would have been an epic place to blow the visual effects budget on. Oh well.

And also there's the part about spaghettification. You don't get spaghettified magically - you get spaghettified like in the medieval torture device where they tie your arms and legs to a frame and then turn a crank to stretch it out until you scream in agony. And then you get drawn and quartered, and then your quarters get drawn and quartered. Nature may not be evil, but it isn't gentle either. Poor astronaut dude would have been in for a really painful experience if he tried that in real life. [/rant]

Oh yeah, and P.S. who else here cringed at their gross misinterpretation of Newton's Third Law? (claiming that you have to drop the shuttles in order to escape because for some reason ditching stuff automatically makes you go faster)

I did love the part where the guy had to dock with a spinning ship. I tried that in KSP once... ONCE. Took the whole blasted day and in my case the ship was barely rotating. 'Course they did have the convenient benefit of a docking port right on the rotational axis xD

Edited November 26, 2014 by parameciumkid

[Nibb31]

I thought they were really lucky that the explosion set the uncontrolled Endurance spinning exactly on it's longitudinal rotation axis. In real life, a chaotic explosion it would have put the rotation on a random axis, which would have made docking impossible.

Edited November 26, 2014 by Nibb31

[cicatrix]

I once managed to dock with uncontrollable rotating debris (a fuel tank actually). I thought I would rub F9 button down to its base in the process but I actually managed it (MJ's smart S.A.S. helped a lot though). I wouldn't want to repeat this ever again. I even went as far as to add control cores and radioisotope power sources to my circularization stages.

[lajoswinkler]

Never seen that poster on official sources. Must be fake.

And an Atlas V can't launch 2 Rangers, only a small satellite or probe.

Yes. One of the largest cinema franchises in Europe sports fake posters.

Have you ever seen a movie? There's some liberty in the making of it.

I thought they were really lucky that the explosion set the uncontrolled Endurance spinning exactly on it's longitudinal rotation axis. In real life, a chaotic explosion it would have put the rotation on a random axis, which would have made docking impossible.

It did rotate on a random axis. It is visible when the two docking ports are close together. There's wobbling. BTW, as far as I know, those were actual models, and not CGI, for which I applaud Nolan's team.

Probably the best scene in the movie. Very powerful with awesome music.

Months ago I tried doing stuff in KSP, similar scenarios, so watching this on a big screen was something I could appreciate even more.

[RogueMason]

-snip-

-more snip-

Oh yeah, and P.S. who else here cringed at their gross misinterpretation of Newton's Third Law? (claiming that you have to drop the shuttles in order to escape because for some reason ditching stuff automatically makes you go faster)

-even more snip-

I'm pretty sure the one they wanted was Newton's Second Law; F=ma perfectly fits. Of course, it's more complex than just F=ma, but it fits. I didn't cringe, just mentally corrected them. No big deal for a film that has become one of my favourites

[lajoswinkler]

I've tried to perform the docking with a fast rotating, poorly precessing object in KSP. It is very, very difficult and if there weren't magnetic properties of the ports, I'd never do it.

Original soundtrack helped a lot.

[Gan_HOPE326]

I hope I'm not too egregiously late to the party, but I just saw the film today.

Overall I think it was good, though definitely not Nolan's best film. I ended up paying very little attention to the orbital physics (fortunately), so those didn't end up irritating me as much as they might have. However.

I'll be the millionth person to rant that the scene where he goes into Gargantua is a bunch of hooey. I did actually sort of call that he'd end up being the "ghost" / "Them" early in the film, so by the time he went in I basically knew what was coming (It's full of stars!). But I hope this movie doesn't go giving anyone any bright ideas about jumping into black holes because they glossed over what we do know (as well as we can hope anyway) about what's inside that event horizon.

First things first, it's kinda sad that they didn't take the opportunity to show what it'd look like to um... I forgot his name. McConaughey. To him as he went in. We know already that the event horison is only black from outside - from inside, you can't really tell when you've gone past it at first, until everything starts going all blue-shifted and yadda yadda yadda. That would have been an epic place to blow the visual effects budget on. Oh well.

And also there's the part about spaghettification. You don't get spaghettified magically - you get spaghettified like in the medieval torture device where they tie your arms and legs to a frame and then turn a crank to stretch it out until you scream in agony. And then you get drawn and quartered, and then your quarters get drawn and quartered. Nature may not be evil, but it isn't gentle either. Poor astronaut dude would have been in for a really painful experience if he tried that in real life. [/rant]

Oh yeah, and P.S. who else here cringed at their gross misinterpretation of Newton's Third Law? (claiming that you have to drop the shuttles in order to escape because for some reason ditching stuff automatically makes you go faster)

I did love the part where the guy had to dock with a spinning ship. I tried that in KSP once... ONCE. Took the whole blasted day and in my case the ship was barely rotating. 'Course they did have the convenient benefit of a docking port right on the rotational axis xD

My interpretation of that was

for the spaghettification, it's been shown clearly that Gargantua is, well, gargantuan. Probably a supermassive black hole with many million suns of mass. Otherwise, that planet couldn't have survived orbiting it close enough to have such a high time warp factor, nor the astronaut would have managed to pass the event horizon without harm. Given that, it might as well be that he never reached the point of spaghettification - after all Magical Future Humans managed to snatch him away and put him into their Tesseract space or whatever. So there's that, I say he simply was caught before he got too close to the singularity (that thing must have been several million km in radius anyway).

For the ships/3rd law, I just assumed they counted on ejecting all that mass with explosive bolts to gain a bit of momentum, plus of course losing mass. So yeah, not 100% exact but people complained about the science being "too convoluted" like this already .

On another note, am I the only one who was calculating DeltaV and ISP for that amazing atmospheric lander of theirs in his head during the movie ? That was truly something, atmospheric decent without parachutes AND take off on two Earth-like planets in a row with no refuel and no stages. Must have been an atomic motor .

Edited November 27, 2014 by Gan_HOPE326