Project Hail Mary by Andy Weir (2021): my attempt at interstellar ship design and flight, NOW A MISSION REPORT!

[Hyperspace Industries]

On 7/22/2021 at 11:09 AM, AGGH said:

Hi all,

I have a question about the novel, which may have been answered eloquently in the novel and I may have missed it, so I will ask it here instead:

If the  'Taumoeba' feeds on Astrophages and destroys it, where is all the energy stored in the Astrophages gone? Surely energy can't just disappear just because Taumoeba consumed the Astrophages. I ask because this is a critical part of the narrative, and changed the entire course of the story. What Dr. Grace saw when he opened the fuel lines, was smelly black gunk which is the byproduct caused by the Taumoeba consuming astrophages. He even considered using the methane formed as a fuel, however, that proved to generate very little energy compared to what he needs to travel back home to earth. Can someone shed light on this? in a nutshell: what happens to the energy stored in Astrophages once they are consumed by taumoeba?

Thanks in advance,

Aghiad 

I don't know, but a it probably gets used by the taumoeba and what's left of the astrophage gets turned into the gunk and methane, the reason this can work is because while astrophage carry a ridiculous amount of energy, that is distributed over many as in millions if not billions of cells, therefore making it possible for a taumoeba to eat an astrophage without having to dissapate a volcano's yearly heat output in one blast. Just a theory, but I think it matches well with things in the book.  
edit: @Saarthakhas replied with a much better and more logical theory.

Edited August 2, 2021 by Hyperspace Industries
Clarified "many"

[Saarthak]

@AGGH This concept was not picked up in the novel at all, however, the mass-energy concept and how astrophage utilizes the concept has been explicitly stated. If you remember the discussion between Dr. Lokken and Dr. Grace, she shows him a paper that is the most advanced theory on the concept; astrophage has the mass-equivalent of it's energy stored as neutrinos and when two of them collide, photons are released with energy adhering to the famous mass-energy equation, and with the particular Petrova wavelength (25.984 micron).

Since the key to energy release in astrophage is neutrino annihilation, the energy is actually stored up as mass as long as the astrophage is conserved (the fuel astrophage, that is), and taumoeba eating it up is consuming mass, not the equivalent converted energy. And since taumoeba have no such energy conversion mechanism, the mass remains mass, and energy doesn't come up at all.

Please correct the theory wherever faulty.

[Hyperspace Industries]

16 minutes ago, Saarthak said:

@AGGH This concept was not picked up in the novel at all, however, the mass-energy concept and how astrophage utilizes the concept has been explicitly stated. If you remember the discussion between Dr. Lokken and Dr. Grace, she shows him a paper that is the most advanced theory on the concept; astrophage has the mass-equivalent of it's energy stored as neutrinos and when two of them collide, photons are released with energy adhering to the famous mass-energy equation, and with the particular Petrova wavelength (25.984 micron).

Since the key to energy release in astrophage is neutrino annihilation, the energy is actually stored up as mass as long as the astrophage is conserved (the fuel astrophage, that is), and taumoeba eating it up is consuming mass, not the equivalent converted energy. And since taumoeba have no such energy conversion mechanism, the mass remains mass, and energy doesn't come up at all.

Please correct the theory wherever faulty.

Well, I stand corrected, that makes much more sense, But I will leave my theory up here just with a small note that I think your theory is a more sensible alternative, anyways, I also want to say to anybody interested in talking about the book should instead try to make a thread in the lounge area of the forums dedicated to the book, as this is a mission report thread, (I am sorry if that sounded rude I wasn’t trying to be. )

[Kimera Industries]

I'm guessing the energy in the astrophage is stored in the taumoeba for later use or in case the taumoeba can't find any astrophage to munch on for a while or to help digest its next meal, as that may take a lot of energy, but who knows?

does that answer your question?

[Kekkie]

Hello again, Kerbonauts!

Sorry I've been away for a while. This is just a quick update post - the project is NOT dead, with a mission report soon to come.

@chimera industries@AGGH @Hyperspace IndustriesBoth of your theories are probably correct in some way - the Astrophage is eaten by the Taumoeba as mass, not energy - but it can probably consume energy and turn it into mass (indirectly - using it for ATP production).

Thank you all for your patience. See you soon, with:

 

PROJECT Hail Mary

THE MISSION REPORT

[Kimera Industries]

Yes, in the book it is confirmed that astrophage turns its energy into mass, (non-enriched astrophage vs. enriched- 19 nano grams) so the taumoeba is merely eating that extra mass.

[Kekkie]

It's not dead! 

https://forum.kerbalspaceprogram.com/index.php?/topic/207169-project-hail-mary/#comment-4100327

[Akagi]

OK, time to make homemade Hail Mary!

[Akagi]

I read the Japanese version and I love the series! Will you make the Blip-A?

[Akagi]

How do I open the .cfg files?

[Akagi]

It works!

[schlosrat]

Hey great mod! Loved the book, and can't wait for the movie - but in the meantime I can explore and have some fun with astrophage engines!

Quick question: Was it intentional that the the MiniAstrophageEngine have the exact same mass (2.0 tones) and the exact same thrust (10000) as the larger engine? That doesn't make sense to me. The Mini has a rescale factor of 4 making it 1/4 the size in each dimension, so really it's (1/4)^3 or 1/64 the volume. How could it possibly retain the same mass and why would it produce the same thrust? The ISP should remain the same since the fuel and technology are fundamentally the same, but not mass or thrust.

Also, why would the engine response time be so very slow? The engine appears to be modeled after ion engines in KSP, which do have a very slow response time of 0.5, but what would give an astrophage powered engine an even slower response time? Big chemical engines like the Mainsail have a response like 0.001

Here's a quick fix for the engines if you happen to agree. Feel free to tailor to suit yourself. I've set the mass of the mini engine to 1/64th of the main, and divided the thrust by 4 (not sure that math is OK). The response time is 10x slower than the Mainsail for both, which seems OK.

//Fix the Mini Astrophage Engine
@PART[MiniAstrophageEngine]:FOR[ProjectHailKary]
{
    @mass = 0.03125
    @MODULE[ModuleEnginesFX]
    {
        @maxThrust = 2000
    }
    @MODULE[FXModuleAnimateThrottle]
    {
        @responseSpeed = 0.01
    }
}

//Fix the Astrophage Engine
@PART[AstrophageEngine]:FOR[ProjectHailKary]
{
    @MODULE[FXModuleAnimateThrottle]
    {
        @responseSpeed = 0.01
    }
}

 

Edited April 3, 2022 by schlosrat

[schlosrat]

On a similar note, I was wanting more astrophage tanks to play with, so here's a module manager script to take every MonoPropellant tank in your game and make an Astrophage variant of it. I'm really winging it on the conversion of  MonoPropellant to Astrophage, but this seems to give OK results that line up more or less well with the three tanks this mod ships. If anyone has a better sense for that conversion factor please jump in.

Module Manager script to fix a few things with the "stock" astrophage tanks. Note: some parts had a category of Propulsion when they should be FuelTank, also the "stock" large tank had a cost lower than its material, as well as a backwards name ("TankAstrophage" vs. "AstrophageTank" like the other two stock tanks).

// Fix the part cost for the large tank so that it's not less than the cost of the materials needed
@PART[Size3MediumTankAstrophage]
{
	@cost = 20000
	// @category = None
}

// Rename the large tank so that it conforms the the naming scheme used on all other Astrophage tanks
+PART[Size3MediumTankAstrophage]:Final
{
	@name = Size3MediumAstrophageTank
	@title = Kerbodyne S3-7200 Astrophage Tank
	@description = A really big Astrophage fuel tank for really big missions!
	@cost = 20000
}

// Fix the amount held in the 1.25m Astrophage tank
@PART[1.25mAstrophageTank]:Final
{
	@RESOURCE[Astrophage]
	{
		@amount = 10000
		@maxAmount = 10000
	}
}

// Fix the amount held in the mini Astrophage tank
@PART[astrophageTank]:Final
{
	@name = AstrophageTank
	@RESOURCE[Astrophage]
	{
		@amount = 5000
		@maxAmount = 5000
	}
}

// Fix the category and manufacturer for all Astrophage tanks
@PART[*AstrophageTank]:Final
{
	@manufacturer = Weir Technologies
	@category = FuelTank
}

This module manager script will give you Astrophage tanks as variants to all of the monoprop tanks you've got in your game - plenty to choose from to find the right fit for your craft!

// Here we boldly copy each and every monopropellant tank and make astrophage variants!
+PART[*]:HAS[#category[FuelTank],@RESOURCE[MonoPropellant]]:NEEDS[ProjectHailKary]:Final
{
	// Change name
	@name ^= :$:_AstrophageTank: 
	@author = RattPack
	
	// Change title
	@title ^= :^:Astrophage Variant of :

	// Change description
	@description ^= :^:Astrophage vairant! :
	@description ^= :RCS:astrophage:
	@description ^= :rcs:astrophage:
	@description ^= :MonoPropellant:astrophage:
	@description ^= :monopropellant:astrophage:
	// @description ^= :mono:astrophage:
	// @description = Astrophage variant adapted from older pre-existing MonoPropellant tank. Pay no attention to the old MonoProellant paint job, we ran out of money and couldn't afford to replaint it...

	// Change manufacturer
	%manufacturer = Weir Technologies

	// Change TechRequired
	%TechRequired = antimatterPower

	// As a wild guess, any monopropellant tank design modified to hold astrophage costs 10 times as much
	@entryCost *= 10
	@cost *= 10

	// Copy the MonoPropellant resource
	+RESOURCE[MonoPropellant]
	{
		@name = Astrophage  // Update name of resource to Astrophage
		// As a wild guess, astrophage capacity is 70 times whatever the monoprop capactity was
		@amount *= 70
		@maxAmount *= 70
	}

	// Remove the old MonoPropellant resource
	!RESOURCE[MonoPropellant]{}
}

 

Edited April 3, 2022 by schlosrat

[Hyperspace Industries]

11 hours ago, schlosrat said:

Hey great mod! Loved the book, and can't wait for the movie - but in the meantime I can explore and have some fun with astrophage engines!

Quick question: Was it intentional that the the MiniAstrophageEngine have the exact same mass (2.0 tones) and the exact same thrust (10000) as the larger engine? That doesn't make sense to me. The Mini has a rescale factor of 4 making it 1/4 the size in each dimension, so really it's (1/4)^3 or 1/64 the volume. How could it possibly retain the same mass and why would it produce the same thrust? The ISP should remain the same since the fuel and technology are fundamentally the same, but not mass or thrust.

Also, why would the engine response time be so very slow? The engine appears to be modeled after ion engines in KSP, which do have a very slow response time of 0.5, but what would give an astrophage powered engine an even slower response time? Big chemical engines like the Mainsail have a response like 0.001

Here's a quick fix for the engines if you happen to agree. Feel free to tailor to suit yourself. I've set the mass of the mini engine to 1/64th of the main, and divided the thrust by 4 (not sure that math is OK). The response time is 10x slower than the Mainsail for both, which seems OK.

//Fix the Mini Astrophage Engine
@PART[MiniAstrophageEngine]:FOR[ProjectHailKary]
{
    @mass = 0.03125
    @MODULE[ModuleEnginesFX]
    {
        @maxThrust = 2000
    }
    @MODULE[FXModuleAnimateThrottle]
    {
        @responseSpeed = 0.01
    }
}

//Fix the Astrophage Engine
@PART[AstrophageEngine]:FOR[ProjectHailKary]
{
    @MODULE[FXModuleAnimateThrottle]
    {
        @responseSpeed = 0.01
    }
}

 

Sorry about all that, I did that bit of coding for the mod, and it was the first time I ever worked with cfg files, so I had no idea what most of those things did. 

[schlosrat]

13 hours ago, Hyperspace Industries said:

Sorry about all that, I did that bit of coding for the mod, and it was the first time I ever worked with cfg files, so I had no idea what most of those things did. 

No worries! It's a great mod, lots of fun to play with and well integrated with the tech tree. I love all the detail put into how it reflects what's in the book.

You might consider changing the name of the folder to ProjectHailKary (camel case, no spaces). This would  better align with how other mods name their folders and also make it easier for anyone who wants to write module manager scripts that rely on it.

Cheers!

[SSTO Crasher]

I read that book it’s very good

Edited April 17, 2022 by SSTO Crasher

[Gerald Nordley]

Since (presumably) Taumoeba do not have the magical ability to contain neutrinos, and without magic all but an extremely small percentage of neutrinos interact with anything at all--they pass through planets with impunity--so they escape Taumoeba cell membrane at (almost) the speed of light without annihilating each other.  The energy is still there, of course, but not usable.  Entropy in action.