The strength of Luna Titanium

[Seto Kaiba]

Hi folks,

I've been poking at a partial translation of Master Archive Mobile Suit: RX-78 Gundam I'm doing for a friend, and one thing continues to nag at me. I can't find any attempt to quantify the strength of the Gundam's most notorious defensive asset... Luna Titanium alloy armor.

To the best of my knowledge, Luna Titanium is a metal matrix composite (cemented carbide) containing titanium, aluminum, and unspecified rare earth elements. What I can't find is any frame of reference to compare Luna Titanium to a modern armor material, or even a specified thickness for the application of Luna Titanium on the RX-78-2. Has any source ever given an equivalent RHA thickness, shear modulus, or any other objective quantification of the strength of Luna Titanium?

[MythSearcher]

Hi folks,

I've been poking at a partial translation of Master Archive Mobile Suit: RX-78 Gundam I'm doing for a friend, and one thing continues to nag at me. I can't find any attempt to quantify the strength of the Gundam's most notorious defensive asset... Luna Titanium alloy armor.

To the best of my knowledge, Luna Titanium is a metal matrix composite (cemented carbide) containing titanium, aluminum, and unspecified rare earth elements. What I can't find is any frame of reference to compare Luna Titanium to a modern armor material, or even a specified thickness for the application of Luna Titanium on the RX-78-2. Has any source ever given an equivalent RHA thickness, shear modulus, or any other objective quantification of the strength of Luna Titanium?

No, no, no and nope.

The best objective comparative is still in-universe, which is probably the PG manual (words are kinda hard to read on Dalong)
It describe the LT as a foam metal and the foam part will be compressed when hit, absorbing the impact and look as if undamaged(but the next hit will be pretty reduced to normal unfoamed armour, which I assume as GM armour)
Same source said it can take a direct hit from the Zaku machine gun, which is probably as objective as it can get but still as ambiguous as possible.

I will check Gundam Officials and Encyclopeadia ver. 1.5 when I get home if I remember to, but I don't recall detailed explanation in it.

[Gelgoog Jager]

I want to point out that in some old threads we discussed how it seems that different types of 120mm Zaku machine guns used different ammo, specially the M120:

ZMP-50 is a standard MS firearm, using the standard 120mm calibre ammo, magazine drum can hold 100 rounds, with various different ammo types like AP(Armour Piecing), HE(High Explosives), HEAT(High Explosives Anti Tank), etc. Since it was originally developed as a space use MS firearm, its muzzle velocity is slow, and generally speaking it's AP (ammo) is not very effective. the ZMP-50D is the improved version developed for ground combat environment.

M120 has a lower quantity, and uses 120mm [censored word] type short bullet, magazine holds 332 rounds vertically. Speculated to be a sub machine gun developed for strafing against soft targets. Believed to be issued after groud operations. Usually it is used for suppressing soft targets like vehicles and infantry with its higher rate of fire and number of rounds than the ZMP-50. A1 and AS represents (this type).

MMP-78 is uniting the early MIP manufactured MS handheld firearms, generally can be separated into early, middle and late periods. The middle period models are used when the intel of Federation Forces will be fielding MS, so the late period models are improved for (MS)to MS combat. Also uses 120mm calibre ammo, drum can hold 70~100 rounds (estimate)

http://www.mechatalk.net/viewtopic.php? ... 69#p351881

Out of the 3 main types of 20mm Zaku machine gun, the ZMP-50 and MMP-78 both seem to hold about 100 rounds of ammo, but the M120 seems to be able to hold 332 "short bullet" rounds, which seem to be meant for use on the ground against soft targets. I suspect that this is the particular weapon that is proven ineffective against luna titanium alloy.

[MythSearcher]

I want to point out that in some old threads we discussed how it seems that different types of 120mm Zaku machine guns used different ammo, specially the M120:


http://www.mechatalk.net/viewtopic.php? ... 69#p351881

Out of the 3 main types of 20mm Zaku machine gun, the ZMP-50 and MMP-78 both seem to hold about 100 rounds of ammo, but the M120 seems to be able to hold 332 "short bullet" rounds, which seem to be meant for use on the ground against soft targets. I suspect that this is the particular weapon that is proven ineffective against luna titanium alloy.

My own rationalization always put it as that.

Since EFF didn't have MS to begin with, or at least there is no fielded units and no MS to MS combat before the RX-78, Zeon unlikely brought along anti MS ammo, especially when Char's ship just finished a mission and happened to bump into WB.
Anti ship ammo might not even be good against MS, since the ships are usually depicted as not very heavily armoured, and Sentinel further stating the ships have good anti beam defense but not well armoured against mass weapons.(I know it is talking about larger things, but since EFSF ships are launched from Earth, they likely have to strip the weight down to minimal anyway)

The higher ups ordered a unreasonable level of defense, that is to block 120mm Zaku machine gun rounds, the engineers replied with the trick of using non-anti-MS rounds. Sounds legit. The higher ups don't understand much and Zeon will take time to field anti-MS rounds anyway.

[Seto Kaiba]

No, no, no and nope.

The best objective comparative is still in-universe, which is probably the PG manual (words are kinda hard to read on Dalong)
It describe the LT as a foam metal and the foam part will be compressed when hit, absorbing the impact and look as if undamaged(but the next hit will be pretty reduced to normal unfoamed armour, which I assume as GM armour)

Hm... that's a little disappointing. I was hoping for something that'd help put the firepower of anti-MS arms in the early Universal Century into a usable context. (I know a fair number of them are just modern small arms scaled up 10x, but that only gets one so far...)

The "foamed" armor thing is new to me... I've found a couple different sources, including the old Kodansha Gundam encyclopedia from '81 and the Bandai Entertainment Bible #1 glossary definition for "Armer (sic)", which describe Luna Titanium alloy armor as 超硬合金 ("Cemented Carbide"). It makes an awful lot of sense to me, given that Titanium Carbide is extremely hard (sitting comfortably around 9.5 on the Mohs scale and an elastic modulus of approximately 400 GPa) and is also an incredibly effective insulator used in reentry heat shielding for spacecraft. Whatever the rare earths and aluminum are doing in the alloy only seems to make it MORE resilient, but any estimate I come up with for that would be based on modern titanium carbide and that would be lowballing it. I was kind of hoping for a nice clean comparison to rolled homogenous steel armor though...

[Gelgoog Jager]

Don't know if it might be important for the on-going discussion, but supposedly luna titanium can only be produced in zero gravity conditions.

Also, in another thread there was an on going discussion on some fictional minerals/alloys from the Universal Century:

http://www.mechatalk.net/viewtopic.php?f=17&t=17104

[Dendrobium Stamen]

In some ways, annoying as it is, the vagueness of just how tough Luna Titanium is one of the few things that can help "future-proof" it as part of the specs sheets; by simply defining its toughness as "very", rather than giving a direct comparison to a real-world armour material, it precludes this futuristic material being leapfrogged by something in real life?

It's the same principle, I suppose, as disconnecting the AD and UC calendars, so that UC 0001 is simply defined as "some time after AD 2045", rather than a specific year.

[Seto Kaiba]

Don't know if it might be important for the on-going discussion, but supposedly luna titanium can only be produced in zero gravity conditions.

Yeah, that seems to be consistent across a fair few Gundam titles... I'm not sure gravity would really have any kind of significant impact on atomic or molecular bonding, but I suppose if zero-g is used to ensure a completely homogenous metallic matrix it might make sense.

In some ways, annoying as it is, the vagueness of just how tough Luna Titanium is one of the few things that can help "future-proof" it as part of the specs sheets; by simply defining its toughness as "very", rather than giving a direct comparison to a real-world armour material, it precludes this futuristic material being leapfrogged by something in real life?

Haven't we kind of already crossed the zeerust threshold with Universal Century though? Several dozen times? The UC era may not be 15 minutes into the future or a couple years into the past the way Macross's first space war is/was, but it's not THAT far off... only 107 years. They've already benchmarked its energy weapon resistence at only a couple times what modern DEWs can put out and solid ammo weapons can wear it down...

It's the same principle, I suppose, as disconnecting the AD and UC calendars, so that UC 0001 is simply defined as "some time after AD 2045", rather than a specific year.

The backstory to Mobile Suit Gundam UC put the kibosh on the vagueness though... the inaugural president of the Earth Federation, Ricardo Marcenas, is described as having been born in 1983 AD and died at 62 years old when Syam Vist and company destroyed Laplace station shortly after midnight GMT on January 1st UC 0001. That would put UC 0001 firmly at 2045 AD, rather than sometime in the vague spacefuture after that point.