I want to make some more graphics about how I envision this ship and its history. But for now I'll write up how I think the space warp drive worked on this ship. I believe this matches all the lines in the movie.
Anti-matter would be ideal for generating the energy needed to cause the Space Warp Field Generation Metamaterial to bend spacetime and create the warp bubble. The problem is that antimatter is VERY rare and VERY expensive. So a pure anti-matter system cannot be built simply becasue of the cost. A fusion reactor would be way to bulky to launch into orbit. However, a near fission reaction could provide some potentially high energies. The warhead on the old Titan II missile was melted down into fuel pellets. These pellets are fed from hoppers, you can see on the outside of the ship, into a reaction chamber. That chamber generates what I can sub-critical plasma. Basically my thought is that there is enough fission happening to create high energies, but not enough to become a bomb.
This sub-critical plasma is then fed up to each nacelle, where it is combines with antimatter in the domes at the front of each nacelle. Many people misidentify these domes and "bussard collectors," but that doesn't make any sense, becasue a short range test-bed like this would not need to gather hydrogen from space. The anti-matter reaction in these domes boosts the plasma into a highly energized state and it becomes "warp plasma." This plasma is then send down into magnetic holding bottle inside the nacelles. Once these magnetic bottles are full to the desired level the nacelles are considered "charged." The plasma injectors then inject the plasma from each bottle into the specially designed metamaterial tiles. There are no "warp coils" as we know them. They are tiles stacked together to form a cylinder. They exhaust products are vented through the outer surface of each tile and out through the side of each nacelle. This produces that blue glow seen on the sides of the nacelles.
The Phoenix Warp System works as a one shot system. Meaning that it produces enough warp plasma for one "jump." After that the system is spent and had to be refueled.
My biggest challenge was coming up with something that would match the very heavily TNG biased dialogue of
Star Trek: First Contact, while also making it different enough to be considered an older more primitive system. The words the movies uses to describe the system it would be very easy to design it to be just like a TNG warp drive. But then that means warp technology would be stagnant for 300 years. So I wanted something that operated a bit differently.
Outstanding artwork, but I think the recent advent of the controlled re-entry burn for the SpaceX boosters suggests to me that the entire ship, booster and all, was projected for a controlled re-entry and landing right back where it came from in the ICBM silo in Montana. This would also explain why Picard was so fascinated with touching it. The whole ship would be familiar, not just the command module.
If that's your theory then go for it. The reasons why I didn't include that feature are as follows:
1. There doesn't appear to be enough fuel. While I haven't done any calculations yet, based on physical appearance there doesn't seem to be enough fuel to sustain a controlled landing. However, in my theory I am proposing a controlled burn long enough to push the Phoenix into an elliptical orbit. This is after the warp jump, so the Phoenix is further from earth, requiring less fuel to achieve orbit. But I still haven't calculated if it's feasible.
2. No visible landing legs. Current designs require some form of landing legs to extend and support the craft. There is nothing on the Phoenix that could serve this purpose. However, since you propose it's landing in the silo, they could have rigged some sort of cradle to catch the craft in the silo.
3. It's a waste of a good launch. This is the most convincing argument for me. They finally got (what I call) the Space Warp Platform into orbit why would they want to land it? If they were going to perform any further testing they would have to ship it to a new site, attach it to another rocket/missile and launch it again. Such a huge waste of resources. It seems more optimal to me to keep it in orbit; then launch more fuel, additional equipment, the command module and crew on a second rocket. They could then rendezvous in orbit, attach the new parts, refuel the Phoenix, and they're ready for round two. In my history of this vehicle I have it reused four additional times for warp tests.
I also envision that after the tests the space warp section of the Phoenix was left in orbit to rot. After many years some enterprising (pun very much intended) individuals bought or salvaged the Phoenix and began restoring it. They managed to purchase or salvage the command module and at some point the Phoenix was fully restored and in a museum. I want to give the Phoenix a more complex history, something more akin to the H-4 Hercules. Where it's just left to the elements before being saved. Then losing it's home multiple times. In other words I want the Phoenix to almost be lost to history but manages to survive into the future by the skin of its teeth. Maybe I'll throw in some botched restorations like what the NCC-1701 studio model went through. Then in 2163, on it's 100th year anniversary, the Phoenix finally gets the loving restoration it truly deserves.
What's interesting to note is that when Picard is feeling up the Phoenix. He's not actually touching the ship. He's touching the fairing they split away into four pieces after first stage separation. Those pieces would have fallen back to earth and probably landed on some poor farmer's house or something.
