Interstellar - Ranger Spacecraft thoughts/question

[ANWRocketMan]

So I'm obviously on the hype train/plane for Interstellar and I loved the movie. All the religious, moral, humanist and spiritual discussions aside there are a few lackluster things that bothered me.

One thing in particular(which doesn't make sense to me even considering artistic freedom) as to the physics is on the Ranger. Why did they not just fly to the Endurance with the Ranger's own fuel and power? Why did they need a standard rocket? I mean, it obviously had enough fuel to land on Miller's planet(which has higher gravity than Earth and is probably a little bit bigger too) and then take off again AND fly back to the Endurance from near a quite large black hole.

My only guess is that it is antimatter fueled? No other propulsion method makes sense with that kind of payload/fuel ratio as the Ranger has. But that it can't store enough to do what they used it for AND take off from Earth as well. What do you think?

Not only that but, if it is indeed antimatter fueled, where do they get it? Scientific inquiry isn't high on the public's order of business as mentioned. So where do they get the strenuous funds to build and run particle accelerators to produce sufficient amounts of the stuff without having the project exposed?

[Hary R]

So I'm obviously on the hype train/plane for Interstellar and I loved the movie. All the religious, moral, humanist and spiritual discussions aside there are a few lackluster things that bothered me.

One thing in particular(which doesn't make sense to me even considering artistic freedom) as to the physics is on the Ranger. Why did they not just fly to the Endurance with the Ranger's own fuel and power? Why did they need a standard rocket? I mean, it obviously had enough fuel to land on Miller's planet(which has higher gravity than Earth and is probably a little bit bigger too) and then take off again AND fly back to the Endurance from near a quite large black hole

Well the answere to that have nothing to do with science (and not that much about artistic freedom in fact), but with general public perception of a space flight.

I don't know why but if you create (fore a movie) a spaceship like the ranger, and make it an SSTO from earth, the general public will not accept it (deeming it to be impossible), their are used to the power of huge rocket, but put it on an alien planet, well it's the future so it's possible. We know it is stupid unfortunately not the majority of the people that have watched the movie know that (or have the knowledge to understand it).

[RogueMason]

Saving the fuel of the Ranger; no fuel ships rendezvoused with Endurance before they left for Saturn, so saving fuel was a bit of a necessity.

Also, the engines are fusion powered; you can find that out from the Board the Endurance site.

[kerbiloid]

Every time when Professor opened his bedside-locker, he found one dollar banknote.

Always with the same number and an obscene word written in the bottom right corner.

It was a Protagonist's lucky dollar has been dropped into a 5-dimension time loop.

Another time loop was aboard "Ranger".

It contained one Duracell cell and one Cricket ligther.

That was its inexhaustible Fountain of Power.

Feeble at Earth but enormously increased due to colossal Gargantua gravity.

[rtxoff]

I agree with the OP, on one side you have the future ranger ship which is doing incredible things on the other you need that huge SLS to get it into orbit? It's just ridiculous. If mankind created the ranger and lander ships they sure had other means to get it into orbit cheaper then with the SLS. However Hollywood needs their movies to be dramatic and big rockets are more dramatic then small ones

[Nibb31]

One thing in particular(which doesn't make sense to me even considering artistic freedom) as to the physics is on the Ranger. Why did they not just fly to the Endurance with the Ranger's own fuel and power? Why did they need a standard rocket? I mean, it obviously had enough fuel to land on Miller's planet(which has higher gravity than Earth and is probably a little bit bigger too) and then take off again AND fly back to the Endurance from near a quite large black hole.

Because the Apollo-style launch is more spectacular. You're right, it doesn't make any sense. We can just be grateful that it was at least more plausible than anything from Star Trek or Star Wars.

My only guess is that it is antimatter fueled? No other propulsion method makes sense with that kind of payload/fuel ratio as the Ranger has. But that it can't store enough to do what they used it for AND take off from Earth as well. What do you think?

If they have a spaceship that is capable of SSTO and they are capable of assembling the Endurance in the first place, then it wouldn't cost them many more round-trips to just to bring up a bit more fuel. It doesn't look like it's carrying hundreds of tons of fuel anyway.

[andrewas]

Not necessarily.

They *need* the high performance of the Ranger during the mission, the cost of doing it with the SLS is multiplied by the need to haul at least one complete SLS to each target planet. And then you have to contend with boiloff, and getting a large, fragile rocket through the wormhole, and the fact they didn't know about Miller's gravity till after Endurance passed through the wormhole and got direct observations, so an SLS built for Earth wouldn't be up to the job.

The only way to do the mission is with something like the Ranger, so they build and fuel a pair of them no matter the cost.

But none of that applies to to launch from earth, and an old fashioned SLS may well be cheaper than a modern Ranger.

[Nibb31]

But none of that applies to to launch from earth, and an old fashioned SLS may well be cheaper than a modern Ranger.

The Ranger is a reusable SSTO. Additionally, it's pretty small, meaning that its fuel source is quite compact already. I really don't see how launching a Saturn V (or whatever than rocket is), would be cheaper than 2 or 3 more SSTO flights to send up a few extra fuel canisters.

[m4rt14n]

The SLS is a Mac Guffin

[jfull]

They may have been using so many traditional rockets to assemble the Endurance that it wouldn't have mattered if they launched one more with the crew.

The production of fusion-based engines might have been very limited.

[technion]

Having just watched this movie - I was more interested in how you managed to keep the whole thing "the most secret organisation in the world" when you launched a rocket that creates a ball of smoke and then flies over a large area as part of a launch.

[SpaceXray]

It is much cheaper to launch 2 rangers at once this good old cheap chemical rockets than have to fly the Rangers 2 separate times in an SSTO-like ascent which is much longer than a regular rocket launch and people have a higher chance spotting a flying Ranger. Also the Ranger's fuel is drastically more rare and expensive, so if you can launch it with a rocket from Earth then why not? Besides, you also have to launch a separate fuel pod with a Saturn V when you could've already launched both Rangers full of fuel with the same rocket! So yeah, economically a Saturn V is cheaper in this case.

[jwenting]

Having just watched this movie - I was more interested in how you managed to keep the whole thing "the most secret organisation in the world" when you launched a rocket that creates a ball of smoke and then flies over a large area as part of a launch.

Illiminati!

Mind control!

Chemtrails!

IOW, it's fiction. And things like that are why I just ignore any work of fiction that claims any scientific credibility at all (which is sadly most supposed science you get from the media as well as most admitted fiction).

[magnemoe]

Because the Apollo-style launch is more spectacular. You're right, it doesn't make any sense. We can just be grateful that it was at least more plausible than anything from Star Trek or Star Wars.

If they have a spaceship that is capable of SSTO and they are capable of assembling the Endurance in the first place, then it wouldn't cost them many more round-trips to just to bring up a bit more fuel. It doesn't look like it's carrying hundreds of tons of fuel anyway.

Yes, it would make more sense if they used the rocket to lift part of the interstellar ship then launched the ranger as an ssto.

Pretty much like we in KSP mihgt launch an interplanetary ship on an huge rocket, then launch an SSTO plane with crew and you take the ship to Laythe and use the plane.

[Waterlimon]

We could just assume the fuel for the ranger was manufactured in space (on endurance or on some separate craft) for reasons such as "muh 0 g", "muh free vacuum", "muh secrecy", "muh infinite free space to build megastructures in" and "muh space radiation and magnetic fields"

[ajburges]

Most plausible excuse:

Ranger accent profile optimizes mass, not cost. A conventional, staged earth launch could optimize cost.

Even if we could make an ion drive based SSTO in KSP it would probably remain economical to launch it and it's fuel from Kerbin with conventional fuel due to the cost difference between fuel types. Such a craft would still be useful for interstellar work due to the mass savings on fuel which would need to be carried through all future burns. The rocket equation means that an extra payload compounds your costs.

We don't see the same thing in KSP because there isn't much selection in nonconventional fuel: monopropelant has bad ISP, and ion drives lack the thrust to propel most vehicles out of large gravity wells.

[magnemoe]

Well the answere to that have nothing to do with science (and not that much about artistic freedom in fact), but with general public perception of a space flight.

I don't know why but if you create (fore a movie) a spaceship like the ranger, and make it an SSTO from earth, the general public will not accept it (deeming it to be impossible), their are used to the power of huge rocket, but put it on an alien planet, well it's the future so it's possible. We know it is stupid unfortunately not the majority of the people that have watched the movie know that (or have the knowledge to understand it).

Note that the directors also asume the public is more stupid than they are, worst example is probably the humans as power source in matrix. The orginal idea was to use human brains for computing.

Director thought it was to hard to understand and came up with an simpler idea who would be just as weird for people who don't understand how it work and idiotic for anybody who have any knowledge.

the interstellar launch is not as bad, as other say you need rockets to get off earth today and this also set an this is near future not in 200 year setting.

[AngelLestat]

I read the book "the science of interstellar" by Kip Thorne.

There are many things explained there, even the ones that was previously review as inaccurate by other scientist.

Main examples: time dilation, some aspects of the giant wave, the blight, deltav, etc.

My guess both ships use fusion, maybe catalyzed with antimatter (only few grams are needed for this, but the isp has a huge buff).

In the book, he explain many proppulsion methods, but it leaves open to the reader's choice.

There are many maneuvers in the movie that seems very deltav intensive, but there are not so much.

1) miller´s planet is not so close to gargantua, is at 3 au from gargantua, gargantua has 1 AU in radius. But is a super rotating black hole, for that reason that amount of time dilation is possible over miller´s planet even that its orbital speed is only 1/3 speed of light.

2) endurance´s orbits to miller´s orbit and back.

Kip Thorne wanted to use another black hole orbiting gargantua for this maneuver, but Nolan said that it would confuse the audience to have 2 black holes, so they use a neutron star. The problem with a neutron star is that the ranger will need to be very close for such deltav change, so it will break.

3) escaping from man´s planet and falling into the black hole

Some might thoght that it would be needed a lot of deltav to fall in gargantua from miller´s planet, but in fact miller´s planet had an eliptic orbit which periapsis is close to millers planet and apoapsys is at 300 au, even with this, miller´s orbit period was few months.

So if you escape from man´s planet from a bit far from gargantua, a small curse change can make you fall.

Why the ranger is launched from a rocket?

Well, any saving in deltav is welcome, also looks more cool.

About why nobody saw the secret rocket launch?

There was in the past thousands of secret rocket launch to test weapons or other thing which nobody knew, they even detonated secret nuclear bombs.

In the movie scenary normal people did not have much access to technology, so it was not an easy way of comunication. Also if someone discover something, is not enoght to spread the info to the general population.

Edited February 8, 2015 by AngelLestat

[Jovus]

You're still all missing the biggest problem in the science of the movie, which is that they would have all been dead of radiation the second they popped through the wormhole. Gargantua is quite obviously a ULX.

[benjee10]

I could be totally wrong but wasn't the reason they needed the Saturn V to get off Earth but not the other planets because of the tidal forces of Gargantua? They never go into orbit around Miller's planet, so is it possible that the black hole's tidal gravity literally pulled them out of the planet's gravity well after they got high enough? Same with Endurance easily escaping Mann's planet. Would the tidal forces of a supermassive black hole be enough to have that kind of effect?

Still, yeah, the radiation is the biggest plothole but it's one you kind of have to overlook because otherwise there'd be no movie. Whatever the case it was nice to see proper scientific ideas being presented in a major movie in a reasonably accurate way and a depiction of spaceflight that at least felt plausible even if under closer scrutiny it comes apart a bit. Films like Interstellar and Gravity are what we need to get people interested in spaceflight again even if they don't strictly play by the rules.

[AngelLestat]

would have all been dead of radiation the second they popped through the wormhole. Gargantua is quite obviously a ULX.

What ULX means??

There is no radiation, the disk accretion of gargantua is an old one, in process of colling. For that reason shines in visible light, at a temperature close to the sun surface.. With the big area of the accretion disk, it provides heat to the planets around.

I could be totally wrong but wasn't the reason they needed the Saturn V to get off Earth but not the other planets because of the tidal forces of Gargantua?

Miller´s planet is orbiting gargantua, is like 0g. The same that astronauts in the ISS. And the tidal forces are just notice in big bodies as planets (with fluids). Because one side of the planet is at 12000 km of the other.

How much the ranger measure? 30m?

[Technical Ben]

Antimatter infused fusion and/or nuclear fuel would explain this. Antimatter could be a very expensive resource, thus only used for the rangers. Nuclear fuel is of cause not desired to be used on earth, but with an average life span/dissipation is acceptable even with future possible colonisation at the destination.

However, the black hole just makes the whole (see what I did there? ) idea of colonising those places as insane. Wormholes for one thing, time dialation effecting black holes are a big "no go" sign.

[Kibble]

The worst (but not most glaringly obvious) technical plot hole in Interstellar is, if these are people from the future creating the wormhole to another star system to save humanity, why did they choose such a sucky one? I bet there is at least one star system out there that doesn't have horrible cray planets on crazy orbits around a crazy black hole. How about a nice planet orbiting a star?

[crubs]

If the goal is to save fuel, then why not just add one or two external fuel tanks like the the orange shuttle tank? If it could SSTO from a planet with 1.3g, I doubt this would be a problem.

Long-story-short, it's okay to be scientifically inaccurate as long as it's awesome. Conventional rocket launches are far more dramatic.

[Jovus]

What ULX means??

ULX is an acronym for UltraLuminous X-ray source, i.e. an X-ray source that emits with luminosities higher than 10^39 ergs/sec. One of the possible explanations for them is intermediate-mass black holes (black holes with greater than about 500 solar masses but less than 10^5 solar masses, which fits Gargantua).

There is no radiation, the disk accretion of gargantua is an old one, in process of cooling. For that reason shines in visible light, at a temperature close to the sun surface.. With the big area of the accretion disk, it provides heat to the planets around.

No. Either it's still a hot accretion disk - which, for an IMBH (intermediate mass black hole) means shining in the high-ultraviolet falling off to the low radio at the edges - or it's a cool one, which means frequencies below visible light. The system is illuminated, ergo it is the former. (There will almost certainly be no useful middle ground - see below.)

You would be right to point out that high UV wouldn't be that dangerous, but the primary mechanism for X-ray pumping for ULXs that host IMBHs is going to be inverse Compton scattering, which will promote the UV source into hard X-rays. This would continue happening until the disk cooled enough to pass out of the UV/high visible spectrum, after which it dramatically falls off because of the complementary wavelengths of hydrogen.

The long and short of it is, if there's enough light from the accretion disk (or a nearby star) to see by, there's enough radiation to turn you to ash.