[cosmicfish]

Since I am at my computer now and not on my phone, let me go into a little more detail.

You could do TMP cheaper... provided you cut out a lot of stuff. And I mean a LOT. Ultimately, the only technology genuinely NEEDED for the Project is cryogenics, but everything you cut out makes a near-impossible task even harder, and after a while it gets to the point where you are just tilting at windmills.

Also, when I say trillions, I am speaking in 2018 currency - I have not accounted for inflation.

There are three major contributing factors that I see as leading to the cost of the Project:

1) Technological advancement. BEM brings back prototypes of advanced technologies, but that is really little more than a sales gimmick. Someone still needs to invent them and develop them, because time travel doesn't allow for knowledge to come from nowhere. And then you have to invent all the supporting technologies (and there are a LOT) that support all those inventions.

Take the portable laser weapon described in 3ed. Right now, state of the art laser technology would cost me a cool million for a laser that is the right size, but is nowhere near powerful enough to serve as a weapon. Then I would need to add the environmental controls (so that it doesn't melt itself) and a battery pack that would make state of the art modern batteries and capacitors look like something that came out of a pyramid. Heck, we had to tear a small satellite apart because the launch got delayed by a year and we knew that our batteries would have degraded too much in that short amount of time to be viable for the mission duration. And those were expensive, expensive batteries.

Or fusion power. We have already spent many, many billions on fusion power and are not within a century of what TMP needs. Forget about the fusion packs for a moment and consider just the one type of fusion reactor the Project most needs - a unit sized for vehicles with enough power to operate the vehicle and its subsystems, with enough fuel for at least a couple of years. That requires incredible work to first develop the impossible and then develop the advanced materials and techniques required to miniaturize them all.

Add to that the cost of developing all of the tools needed to make all this stuff, because that often gets disregarded. I could make a truly amazing laser right now... if someone would only invent a way to manufacture optical antenna arrays at lambda/2 spacing, and ways to efficiently produce the kind of precision optics. Tooling get surprisingly expensive.

And while people often think that they can use civilian costs for comparison, you really can't. You're buying for an effort that cannot afford for equipment to fail, because it might not be replaceable and someone might die when it breaks. It needs to last a looooooong time on the shelf and work perfectly when you need it. It needs to operate with minimal maintenance and parts, in conditions where you can expect ash, and radioactivity, and combat conditions. This stuff is expensive.

2) The size of the Project. 50,000 people in the Project? If we go with the assumption that 40,000 of those are in field teams, and that there are an average of 8 people per team, that is 5,000 field teams. Each one needs their own bolthole, 6 unique caches, and at least 1 vehicle (preferably two, given the dispersion of the Project). Each bolthole has a fusion reactor, as does each vehicle, so that is 10,000+ compact fusion reactors, 35,000 excavations, and 5,000+ large, militarized vehicles that need to be acquired and modified.

By the way, do you know how many of those vehicles currently exist? Acquiring thousands of militarized vehicles is not something you do off the surplus market, because there aren't that many surplus vehicles available! The ones that ARE available are often being sold because they are near the end of their useful lives - not something you want to buy and then expect to use every day for the next 20 years!

You also need to identify, recruit, and train at least 50,000 people to a degree that will probably be on par with special operations training costs of ~$250k each - that's $12.5B ignoring the recruiting costs. You need to pay them at least until they "die", along with the untold thousands who will work for the Project without ever seeing the inside of a bolthole.

You need more than a hundreds thousand firearms, plus ammunition and accessories. 50,000 CBR kits. How many Science One vehicle are out there, and how much do THEY cost??

The scale is daunting.

3) The secrecy. This serves as a cost multiplier for everything out there. Buying a hundred V-150's and getting them discretely into boltholes is going to be stupid hard. It is going to take bribes, and misdirection, and evading massive government organizations specifically looking for this kind of skullduggery. Doing all that research is going to require building your own labs and finding scientists not only willing to do the work but also willing to keep it all secret (no publishing???). Ordinary security for a classified project adds significantly to the cost of the program, and TMP needs the kind of security that would make the Manhatten Project look like an open air forum. It would be like doing the Manhatten Project, a hundred times larger, as Americans, in Berlin.

Going to the example in your original post, a 3 mile tunnel 24' in diameter... What is the cost of doing THAT in secret? The cost of mineral rights, the cost of evading mining inspectors, the cost of covering up the purpose of the dig, the cost of disposing of the 7 million cf of dirt and rock, the cost of discreetly turning a tunnel into a bomb shelter, the cost of loading all the vehicles and equipment, etc?

So yes, I'll stick with trillions. Scale things drastically back, get rid of every single bit of non-existing technology possible, and you could do it cheaper. But your chances of success, heck, your chances of getting to the war without being discovered and dismantled, get lower with every dollar. And at some point, TMP turns into a pipe dream, a bunch of survivalists with a pie-in-the-sky goal that could never be accomplished in their lifetimes.