Propellant: What is in an MS's Tank?

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Propellant: What is in an MS's Tank?

Post by MinerEdgar » Mon Nov 13, 2017 9:28 pm

So there been discussion on how much propellant a MS can carry, how powerful their engines are, and how fast it move them. But, I haven't seen anyone pin down what exactly they use as propellent. Not fuel, as that is occasionally explained as nuclear thermal power, but the material shot out of the nozzle.

I think i've seen it stated as hydrogen, but that would require cryogenics and isn't very dense. Which would make it awkward to carry an appreciable amount in an MS, though it would fit well with the Nuclear Thermal rocket explanation. Perhaps its some kind of Hypergolic fuel, as that would make it easy for the quick burst of thrust seen in animation and the tendency for a hit suit to explode spectacularly.

Anyone know if its been say in official documentation whats being used? Or, what the most logical explanation would be.

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Re: Propellant: What is in an MS's Tank?

Post by Seto Kaiba » Tue Nov 14, 2017 12:29 am

MinerEdgar wrote:
Mon Nov 13, 2017 9:28 pm
I think i've seen it stated as hydrogen, but that would require cryogenics and isn't very dense. Which would make it awkward to carry an appreciable amount in an MS, [...]
They're already carrying cryofuels... the minovsky ultracompact fusion reactor runs on a mixture deuterium and helium-3, and cryofuels are pretty much the standard for any kind of throttle-able chemical rocket.

MinerEdgar wrote:
Mon Nov 13, 2017 9:28 pm
Anyone know if its been say in official documentation whats being used? Or, what the most logical explanation would be.
The information I've been able to find in Master Archive points to them being liquid fuel rockets, probably hydrogen and oxygen.
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Re: Propellant: What is in an MS's Tank?

Post by MinerEdgar » Tue Nov 14, 2017 1:12 am

Ahhh. I didn't think of the required systems for the reactor. But, there'd need to be been cooling/insulation for each tank, not one central system. I would say there's a lack of space in an MS for such equipment and an reasonable amount of fuel, but I don't know the size of such equipment with Gundams Tech Level nor the efficiency of the engines.

Also, Hypergolic fuels have been use in throttle-able rockets, there were Russian missiles in the sixties that had them. It was toxic as hell and very risky, but they existed.

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Re: Propellant: What is in an MS's Tank?

Post by MythSearcher » Tue Nov 14, 2017 8:15 am

Seto Kaiba wrote:
Tue Nov 14, 2017 12:29 am
MinerEdgar wrote:
Mon Nov 13, 2017 9:28 pm
Anyone know if its been say in official documentation whats being used? Or, what the most logical explanation would be.
The information I've been able to find in Master Archive points to them being liquid fuel rockets, probably hydrogen and oxygen.
Gundam Officials points out during the OYW, most MS and space fighters use thermonuclear rockets.
With an exhaust velocity of 9% of the speed of light.

Exception is listed, RX-78's Core Fighter uses a thermonuclear hybrid engine, that can double as a thermonuclear jet engine within the atmosphere.

By UC0099, almost all space faring crafts including spacecrafts, fighters, MSs, ships uses thermonuclear rockets.
However, there are other systems in use, the Jupiter fleet (and long distance ships like it) mainly uses Nuclear Pulse engines, which uses micro hydrogen bombs and an onboard laser ignition system(Think of them as shooting the GP02A atmoic bazooka every 200s and igniting it right behind the ship); Another is the laser propulsion system, mainly used for fixed trajectory ships to save propellant. Not a photon propulsion system but an external laser heated system on the moon to heat up propellant released on the thrusters of the ship, example is Albion in 0083. Also called the orbital transfer laser or ignition laser.

Thermonuclear rockets isn't really old in UC though. It started to be a viable thruster during the 40's (When the Minovsky-Ionesco fusion engine making it possible) The first military usage is in the late 60's, where Magellan class and Salamis class first utilize it. However, they still have chemical rockets and plasma rockets in most spacecrafts installed along with the thermonuclear rockets.

External propellant tanks also contain coolants for themselves, to prevent dead weight(so the unit can carry minimum coolant that supports its own on board systems)

The propellant, is labelled as liquid Hydrogen in the figure on the same page(P.419), but isn't really mentioned within the paragraph.

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Re: Propellant: What is in an MS's Tank?

Post by Gelgoog Jager » Tue Nov 14, 2017 7:05 pm

Mark once wrote an interesting column about UC MS power sources, which also touched the propulsion issue:

https://web.archive.org/web/20160304173 ... power.html

The relevant part:

...A similar mechanism is used for propulsion. Instead of traditional chemical rockets, mobile suits are equipped with nuclear thermal rocket engines, in which propellant is heated by the reactor and then expelled to create thrust. These devices provide substantially greater fuel efficiency than chemical rocket engines (7), allowing the mobile suit to operate for longer periods and reach higher velocities in space. The same concept can be employed to create nuclear thermal jets and nuclear thermal hydrojets, which employ air and water, respectively, as propellants.

Since thermal energy from the reactor is used to generate both electrical power and rocket thrust, these two applications are competing for the same resource. In theory the allocation of this energy can be shifted back and forth depending on the needs of the moment, but in practice, mobile suits which are designed for high-speed combat often forgo the use of electricity-hungry beam weapons, or use external generators to power their weapons.

When this heat isn't being used for either purpose, it has to be disposed of via radiators or ventilation ducts to prevent the mobile suit from overheating. Since electrical generation, propulsion, and cooling all involve extracting thermal energy from the reactor and transferring it to other parts of the mobile suit's body, why not use the same mechanism for all three? The author imagines a network of thermal energy conduits running throughout the mobile suit's body, transferring reactor heat via high-pressure helium gas (8). This provides a handy explanation for the cables and tubes that decorate the exteriors of our favorite mobile suits (9)...


Before tackling the propellant issue, I want to comment on the heating issue first: early one there were more common mentions of how space use MS needed to be cooled down upon returning to their mothership, as their temperature would be to high after combat. Particularly there were mentions that a Papua class ship could only operate MS-05 units since their facilities were not adequate for cooling down MS-06 units. Now, in recent years MS Igloo redesigned Musai seems to have been widely adopted as an updated version of the original Musai, with Unicorn Gundam going as far as basing their version of the Musai Kai on it. What makes this model stand out from other Musai is the fact that a retrieval hatch has been added in front of the bridge, which supposedly is to be used exclusively for returning MS that need to be cooled down before being sent back into the actual hangar. There are even remakes about this slot, which technically would allow a 4th MS inside the Musai's main hangar, not counting towards the ship's total MS capacity given this particular role.

Back to the topic at hand, the propellant supply issue comes around every now and then in some of the background info of the series. For instance, the MS-09R Rick Dom is adopted as a stopgap unit partially due to the lower skill of new pilots that replaced the veterans that were trained for years before the outbreak of the war and whom perish during the early battles. Supposedly rookies tended to run out of propellant when piloting MS-06F units since they tended to make many wasteful/unnecessary movements. While the Rick Dom is less maneuverable than a Zaku II, for instance in the turning speed, it had a larger propellant supply, which allowed these less experienced pilots to not run out of propellant so easily even if they were wasting propellant.

There's also the peculiar case of the MS-06F direct successors: the MS-06F2 is said to be an overall improvement over the standard F-type, being both lighter and having a larger propellant capacity, extending its operational time. In comparison, the MS-06FZ is a much larger improvement in most areas, save for one: propellant capacity. Supposedly, the propellant capacity of these units remained unchanged form the base F-type units, but their consumption was increased due to the addition for more thrusters, resulting in their propellant running out faster than the original models. It's said that while MS-06F2 units are brand new units, MS-06FZ are likely upgraded from existing MS-06F which by the end of the OYW are in need of an upgrade to keep up, so perhaps the unchanged propellant capacity is derived of this particular situation. It's also worth noting that the UMP siblings of the Zaku Kai, the MS-09R2 Rick Dom II and MS-14JG Gelgoog Jager, also faced similar problems given their own improvement over their respective base model, however in the case of these two models external propellant tanks were added to offset the higher propellant consumption.

Anyway, it's worth nothing that the Principality of Zeon did work on some projects to extend the operational time of their space use MS, including a MS-06F unit modified with additional propellant tanks, the MS-14C-1A plan for the Gelgoogs (which could be implemented on other models, such as Uma's MS-14B) or the Skute sub-flight system (predating the models that would debut during the Gryps Conflict 7 years later) that could give an MS a ride to the battlefield and then be discarded, thus saving the MS own propellant supply for the actual combat:

http://gundam.wikia.com/wiki/MS-06_Zaku ... lant_Unit)
http://gundam.wikia.com/wiki/MS-14C-1A_Gelgoog_Cannon
http://gundam.wikia.com/wiki/MS-14B_Gel ... ing_Custom
http://gundam.wikia.com/wiki/Skute

A less orthodox case is that of the MA-05AD Big Rang and the MP-02A Oggos, the later which could be resupplied in the field by docking with the Big Rang.

As a bonus note, supposedly in the original script for the first Gundam TV series (when it was still aiming at end at around 50 episodes), during their space campaign the EF would launch an attack against the Jovian Energy Fleet (a neutral faction that provided the valuable Helium 3 to both sides of the conflict) in order to disrupt the Principality of Zeon's supply of the vital fuel. Ultimately that idea was scrapped, but the Jupiter Energy Fleet (JEF) would become relevant again thanks to Scirocco Paptimus who commanded one of the Jupiter's class ships of the fleet, as well as its relevant at the end of the 1st Neo Zeon conflict and during the events of Crossbone Gundam. Given how much of the UC universe revolves around the 7-year long supply runs of these ships, it was interesting seeing how they could take the spotlight in some of the post-OYW conflicts.

I do wonder if the Principality of Zeon might have had a fleet of its own for collecting helium-3, or at least provided escort for the JEF as hinted on a MS Era picture. For what may be worth, Challia Bull, pilot of the Braw Bro, is said to have just returned from Jupiter before being assigned to test the MAN-03, so perhaps there could be some truth to it:

https://vignette.wikia.nocookie.net/gun ... 0216061037

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Re: Propellant: What is in an MS's Tank?

Post by MinerEdgar » Wed Nov 15, 2017 2:26 am

Ahh, Very informative. Thank you Jager.

I wonder if there would be an issue of a suit overheated to a point where the insulation fails and the hydrogen detonates, i suppose worse things would be happening by that point. Interesting to hear about the other forms of propulsion in UC, i didn't remember the laser system in 0083. And the pulse system of the JEF, i didn't know that concept was in gundam. I do wish they went into more detail on the whole Jupiter operations.

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Re: Propellant: What is in an MS's Tank?

Post by MythSearcher » Wed Nov 15, 2017 9:02 am

Gelgoog Jager wrote:
Tue Nov 14, 2017 7:05 pm

I do wonder if the Principality of Zeon might have had a fleet of its own for collecting helium-3, or at least provided escort for the JEF as hinted on a MS Era picture. For what may be worth, Challia Bull, pilot of the Braw Bro, is said to have just returned from Jupiter before being assigned to test the MAN-03, so perhaps there could be some truth to it:

https://vignette.wikia.nocookie.net/gun ... 0216061037
The official time line in both Gundam Officials and Encyclopaedia Ver. 1.5 note that the Jupiter Energy Development fleet started sometime before 0010, and reorganized in 0010 and started the development of Jupiter Business. Usually seen as at least the start of the Jupiter Energy Fleet.
While Zeon sent out their 1st own Jupiter fleet in Oct 0070, and it returned in Dec 0074. They had some kind of problem during the voyage and a lot of crew member had mental issues.

Challia Bull is presumably one of those crew members or one of those in the 2nd or 3rd mission the Zeon sent out before 0079. Each mission only takes 4 years or less, and they can send fleets without waiting for the first to return, by 0089(by the time Judah joins), the Jupiter Fleet seems to be able to return in a matter of months.

The picture depicted in MS Era must be of a 2rd or later mission, since they don't have Zakus before 0075.
MinerEdgar wrote:
Wed Nov 15, 2017 2:26 am
Ahh, Very informative. Thank you Jager.

I wonder if there would be an issue of a suit overheated to a point where the insulation fails and the hydrogen detonates, i suppose worse things would be happening by that point. Interesting to hear about the other forms of propulsion in UC, i didn't remember the laser system in 0083. And the pulse system of the JEF, i didn't know that concept was in gundam. I do wish they went into more detail on the whole Jupiter operations.
It's actually quite detailed in Gundam Officials, but too long, don't want to translate and hard to get the pictures scanned.

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Re: Propellant: What is in an MS's Tank?

Post by Seto Kaiba » Wed Nov 15, 2017 11:56 am

Ah, that makes a fair amount of sense... they're monopropellant rockets using heat diverted from the fusion reactor to flash-expand the propellant to provide thrust instead of relying on combustion.

(Still, why are they letting all that heat go to waste? Why doesn't the reactor use thermoelectric converters to supplement its MHD output?)
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Re: Propellant: What is in an MS's Tank?

Post by Seto Kaiba » Wed Nov 15, 2017 12:10 pm

MinerEdgar wrote:
Wed Nov 15, 2017 2:26 am
I wonder if there would be an issue of a suit overheated to a point where the insulation fails and the hydrogen detonates, i suppose worse things would be happening by that point.
Now THAT one I can answer... if the performance of the Zimmad EMS-04 (or EMS-10) Zudah and the RGM-79s in the Mobile Suit Gundam: MS IGLOO OVA "The Hidden One Year War" are any indication, running the thrusters past their redlines for more than a brief period has the disquieting outcome of causing the suits to explode or to start breaking up under the strain, sometimes both.
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Re: Propellant: What is in an MS's Tank?

Post by MythSearcher » Thu Nov 16, 2017 8:17 am

Seto Kaiba wrote:
Wed Nov 15, 2017 11:56 am
Ah, that makes a fair amount of sense... they're monopropellant rockets using heat diverted from the fusion reactor to flash-expand the propellant to provide thrust instead of relying on combustion.

(Still, why are they letting all that heat go to waste? Why doesn't the reactor use thermoelectric converters to supplement its MHD output?)
They probably can't.
Firstly, they are not using waste heat for the propulsion, they actually pump the hydrogen into the fusion lattice(I-field holding onto the D and He3) so the propulsion system actually uses the output power and not the waste heat.

Secondly, Minovsky Fusion generators basically is a type of cold fusion, they don't generate really high temperature, not saying it is room temperature, but a working MS only gets to a few hundreds degrees C after 10 mins of operation, and don't get much higher than that. Considering the difficulty to dissipate heat into space, the generators are really efficient and you probably can't get much more from it with thermoelectric converters.

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Re: Propellant: What is in an MS's Tank?

Post by Seto Kaiba » Thu Nov 16, 2017 1:58 pm

MythSearcher wrote:
Thu Nov 16, 2017 8:17 am
Seto Kaiba wrote:
Wed Nov 15, 2017 11:56 am
(Still, why are they letting all that heat go to waste? Why doesn't the reactor use thermoelectric converters to supplement its MHD output?)
They probably can't.
... that makes absolutely no sense whatsoever.

Everything I can find on the subject of how Mobile Suits convert the energy of the thermonuclear fusion going on inside their Minovsky CTRs, from the original Entertainment Bibles right on up to recent Master Archive Mobile Suit books points to them using magnetohydrodynamic dynamos as their main generators and Rankine cycle turbine generators as their topping cycle. Both of those are LOSSY AS HELL, MHD dynamos top out around 22% efficiency, and Rankine cycle generators usually run at around 40% efficiency. Using both together produces generator efficiency of around 60%. Given that, outside of the Minovsky particle, the Universal Century's tech is not capable of violating the conventional laws of physics it's unlikely that they have significantly improved upon those numbers with either generator technology.

Approximately 40% of the usable energy output of the reaction is being dissipated as waste heat via the reactor's cooling system. Helium-3 is EXPENSIVE. It's imported from Jupiter. It's absolutely insane that they wouldn't use thermoelectric converters to assist cooling in the cooling system and Rankine cycle generator to further improve generator efficiency. It's a criminal waste of energy. With minimal additional complexity they could reduce the burden on the cooling system AND convert more reactor heat into usable energy. This technology can be easily installed on automobile combustion engines (and has been used on a trial basis for a while now), so applying the same technology to a power system that runs a good deal hotter could only improve things.


MythSearcher wrote:
Thu Nov 16, 2017 8:17 am
Firstly, they are not using waste heat for the propulsion, they actually pump the hydrogen into the fusion lattice(I-field holding onto the D and He3) so the propulsion system actually uses the output power and not the waste heat.
As it's heat energy intended for power generation being exhausted into the surrounding atmosphere, it technically becomes waste heat as a result of that diversion... but fair enough.

Mind you, the official explanation provided doesn't say anything about pumping the propellant into the Minovsky reactor's core, just that heat energy from the reactor is used to heat the monopropellant used in the rocket. An assortment of different heat transfer technologies can be used to achieve this effect without anything as utterly reckless and nigh-impossible as attempting to pump the rocket propellant through an ongoing fusion reaction.


MythSearcher wrote:
Thu Nov 16, 2017 8:17 am
Secondly, Minovsky Fusion generators basically is a type of cold fusion, [...]
No, it is not. It's explicitly identified as thermonuclear fusion... by definition, atomic fusion catalyzed by extremely high temperatures (and pressures).


MythSearcher wrote:
Thu Nov 16, 2017 8:17 am
they don't generate really high temperature, not saying it is room temperature, but a working MS only gets to a few hundreds degrees C after 10 mins of operation, and don't get much higher than that.
Ah, no. The fusion temperature of deuterium and helium-3 starts at around 1.2 megakelvin under compression, around 1.1 million degrees centigrade (or 1.98 million degrees fahrenheit for those in the US). This is achieved through I-field lattice compression of the deuterium and helium-3 fuel. The reason given for the comparatively light cooling system requirements of the Minovsky ultracompact thermonuclear fusion reactor is that the i-field lattices used to compress the fuel past the fusion point and contain the resulting plasma are also dense enough that they block much of the resulting infrared radiation. This also assists in maintaining the fusion reaction, as those i-fields keep the heat from the reaction largely bottled up in the plasma, reducing the amount fuel input that the reactor needs to sustain fusion.


MythSearcher wrote:
Thu Nov 16, 2017 8:17 am
Considering the difficulty to dissipate heat into space, the generators are really efficient and you probably can't get much more from it with thermoelectric converters.
See the above for why this isn't quite right... but the small scale of the fusion reaction also helps keep the waste heat dissipation down. There is something said about the cooling problem in an earlier post as well which you'd probably find relevant to my point.
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Re: Propellant: What is in an MS's Tank?

Post by MythSearcher » Fri Nov 17, 2017 11:17 am

Seto Kaiba wrote:
Thu Nov 16, 2017 1:58 pm
MythSearcher wrote:
Thu Nov 16, 2017 8:17 am


They probably can't.
... that makes absolutely no sense whatsoever.

Everything I can find on the subject of how Mobile Suits convert the energy of the thermonuclear fusion going on inside their Minovsky CTRs, from the original Entertainment Bibles right on up to recent Master Archive Mobile Suit books points to them using magnetohydrodynamic dynamos as their main generators and Rankine cycle turbine generators as their topping cycle. Both of those are LOSSY AS HELL, MHD dynamos top out around 22% efficiency, and Rankine cycle generators usually run at around 40% efficiency. Using both together produces generator efficiency of around 60%. Given that, outside of the Minovsky particle, the Universal Century's tech is not capable of violating the conventional laws of physics it's unlikely that they have significantly improved upon those numbers with either generator technology.

Approximately 40% of the usable energy output of the reaction is being dissipated as waste heat via the reactor's cooling system. Helium-3 is EXPENSIVE. It's imported from Jupiter. It's absolutely insane that they wouldn't use thermoelectric converters to assist cooling in the cooling system and Rankine cycle generator to further improve generator efficiency. It's a criminal waste of energy. With minimal additional complexity they could reduce the burden on the cooling system AND convert more reactor heat into usable energy. This technology can be easily installed on automobile combustion engines (and has been used on a trial basis for a while now), so applying the same technology to a power system that runs a good deal hotter could only improve things.
No, it is not. It's explicitly identified as thermonuclear fusion... by definition, atomic fusion catalyzed by extremely high temperatures (and pressures).
This is a type of catalyze fusion and while we can question the wording thermonuclear, it is not a single instance of loose vocabulary in UC settings. Getting to 10,000 degrees C is still cold compared to the billion degrees nuclear fusion we have in view, but still pretty hot in normal sense.

The reason of what you think doesn't make sense is the generators doesn't work like an MHD.
They don't generate electricity from heat, they generate electricity through the interaction from the I-field lattice.
Gundam Officials and Encyclopaedia Ver. 1.5 both explained the Minovsky Ionesco Type Thermonuclear Fusion Generator to be working in this manner: Setting up an I-field lattice inside the chamber, compress it with an EM field and you get something called a super lattice when the distance between the M particles is reduced to a certain limit, then the M particles will turn the energy into mass according to E=mc^2, when the mass or each M particle exceeds the mass of a proton/anti-proton, fill the lattice with a plasma of D and He3 and they will form particle-like structures with the positive and negative charge M particles, and later molecule-like structures, further compress the lattice to create the environment of fusion, and once the fusion starts, the I-field expands and the electric charge interaction from the lattice is used to generate electricity. Which you get "extremely high efficiency".

Whatever radiation generated by the fusion is basically blocked by the lattice and thus also became a part of the electricity generation process. This includes heat radiation.

Gundam Century basically is the source of this explanation and only also confirms the propellant to be liquid hydrogen and is pumped into the core instead of around it. While imidam 0093 from Gundam Wars III Sentinel only briefly mentioned the role of Minovsky lattice in the reactor, "Universal Century Science Reader" (宇宙世紀科学読本) has the same explanation, only more detailed as GO, ver. 1.5 and GC.

The Rapport Deluxe books didn't have much on the topic, and the EB UC Box only had a really short paragraph about what a Nuclear Fusion reactor is(and misspelled fusion as tusion along with many other engrish spellings), don't even have a picture of a generator or insisting they are called thermonuclear reactors like Gundam Officials.(Yes, Officials actually had a sentence emphasizing they are thermonuclear before going into detail to disprove the sentence)

These are pretty much the most authoritative sources to my knowledge, and I have yet to see more detailed explanation than the Gundam Officials and UC science reader.
As it's heat energy intended for power generation being exhausted into the surrounding atmosphere, it technically becomes waste heat as a result of that diversion... but fair enough.

Mind you, the official explanation provided doesn't say anything about pumping the propellant into the Minovsky reactor's core, just that heat energy from the reactor is used to heat the monopropellant used in the rocket. An assortment of different heat transfer technologies can be used to achieve this effect without anything as utterly reckless and nigh-impossible as attempting to pump the rocket propellant through an ongoing fusion reaction.
The above sources all had even lengthier paragraphs on the propulsion except UC science reader(which merged the two description and only had a short paragraph on propulsion), and Gundam Century actually gave us the 10,000 degrees C figure.

The propellant is safely transferred through the core thanks to the I-field lattice, or magic if you like to call it, so, it makes no sense at all IRL, just like the Minovsky-Ionesco Thermonuclear reaction.

Ah, no. The fusion temperature of deuterium and helium-3 starts at around 1.2 megakelvin under compression, around 1.1 million degrees centigrade (or 1.98 million degrees fahrenheit for those in the US). This is achieved through I-field lattice compression of the deuterium and helium-3 fuel. The reason given for the comparatively light cooling system requirements of the Minovsky ultracompact thermonuclear fusion reactor is that the i-field lattices used to compress the fuel past the fusion point and contain the resulting plasma are also dense enough that they block much of the resulting infrared radiation. This also assists in maintaining the fusion reaction, as those i-fields keep the heat from the reaction largely bottled up in the plasma, reducing the amount fuel input that the reactor needs to sustain fusion.
Whatever energy comes out from the fusion process is basically pushing the I-Field lattice outwards, and that is what they used to generate electricity. Thus you don't really have waste heat and you don't really need to heat up the fusion fuel to extreme temperatures to begin with(other than getting them to a plasma stage).
See the above for why this isn't quite right... but the small scale of the fusion reaction also helps keep the waste heat dissipation down. There is something said about the cooling problem in an earlier post as well which you'd probably find relevant to my point.
Ok, if we do a simple calculation, the surface of a MS can be guesstimated to be around 200m^2 (being the higher end of the human skin area of 1~2m^2 times 100) and surrounding temperature as 3K and emissivity coefficient 0.64.
With the nice calculator (Radiation Heat Transfer Calculator) in Engineering Toolbox:
https://www.engineeringtoolbox.com/radi ... d_431.html
At around 200 degrees C, you get about 360kW, that is indeed a really sizable amount of heat compared to the generator outputs figures we get that is around 1,000~1,500kW in OYW.

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Re: Propellant: What is in an MS's Tank?

Post by Phonix_1 » Tue Nov 21, 2017 12:22 pm

MythSearcher wrote:
Tue Nov 14, 2017 8:15 am
Gundam Officials points out during the OYW, most MS and space fighters use thermonuclear rockets.
With an exhaust velocity of 9% of the speed of light.
0.09c...the exhaust is the plasma from onboard reactor? So they are not using nuclear thermal engines, right?
MythSearcher wrote:
Tue Nov 14, 2017 8:15 am
Exception is listed, RX-78's Core Fighter uses a thermonuclear hybrid engine, that can double as a thermonuclear jet engine within the atmosphere.
Though it is not consider as a problem in Gundam, it can be very dangerous to use fusion mode in some places, even in space.
Can the nuclear engine use some kind of plasma mode instead?
MythSearcher wrote:
Tue Nov 14, 2017 8:15 am
By UC0099, almost all space faring crafts including spacecrafts, fighters, MSs, ships uses thermonuclear rockets.
However, there are other systems in use, the Jupiter fleet (and long distance ships like it) mainly uses Nuclear Pulse engines, which uses micro hydrogen bombs and an onboard laser ignition system(Think of them as shooting the GP02A atomic bazooka every 200s and igniting it right behind the ship); Another is the laser propulsion system, mainly used for fixed trajectory ships to save propellant. Not a photon propulsion system but an external laser heated system on the moon to heat up propellant released on the thrusters of the ship, example is Albion in 0083. Also called the orbital transfer laser or ignition laser.
Jupiter ships use nuclear pulse engines, not fusion rockets, even the latter one is widespread.
Does this indicate that Jupiter transport ships are some older designs?

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Re: Propellant: What is in an MS's Tank?

Post by MythSearcher » Tue Nov 21, 2017 9:44 pm

Phonix_1 wrote:
Tue Nov 21, 2017 12:22 pm
0.09c...the exhaust is the plasma from onboard reactor? So they are not using nuclear thermal engines, right?
From the figure they embeded, The reactor/rocket is a circle with 3 opennings in a Y shape configuration, one openning is for the fusion fuel, one openning is for the hydrogen propellant tank and one for the exhaust.
Outside the core there is a controlling coil that surrounds it, and inside it is labelled as the fusion plasma.

Some magic happens and only the hydrogen is propelled, and I guess the fusion product is also used, but there isn't any explanation in detail.
Though it is not consider as a problem in Gundam, it can be very dangerous to use fusion mode in some places, even in space.
Can the nuclear engine use some kind of plasma mode instead?
Not specified, but before the widespread use of nuclear fusion, the spacecrafts in UC used Plasma rockets, and before that, Ion thrusters.

They do have secondary systems of plasma rockets and/or ion thrusters on most spaceships.
Jupiter ships use nuclear pulse engines, not fusion rockets, even the latter one is widespread.
Does this indicate that Jupiter transport ships are some older designs?
No, they are just more suitable on larger ships.
Once your size gets too small, the bombs aren't efficient anymore. The casing will take up a higher portion of mass on the bombs and the protection from the blast(which is electromagnetic in UC) gets a higher ratio of mass of your craft as well.

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