Project ZTC Tortoise Lunar Capsule

[n0mad23]

Back when I was working on the Ananke Tether-Sling project, when tblaxland was working on the code for its own dll, I did a kind of mock-up of a lunar craft I wanted for the cislunar tether platform. Originally, this craft was going to be utterly dependent on a rotovator for getting onto and off of the Lunar landing sites. You can see some of the project still in this thread - http://www.orbiter-forum.com/showthread.php?t=684&page=13

Unfortunately, I burned up 3 motherboards on my laptop in those final days, and by the time I got to replace it, Orbiter and addon development got put onto a back burner.

Recently I've sat down to revise a novel I've been picking away at for some time, and saw a great opportunity for rewriting the section I'd done involving the Ananke Tether-Sling and the Tortoise Lunar Capsule. In rethinking this section, I decided to recreate the Tortoise and create a kind of intermediate step to facilitate its use without the Lunar Rotovator.

Here's the Tortoise Lunar Capsule (ZTC-TLC) reimported into Anim8or and ready to be reverse engineered. The Tortoise, from my earliest discussions with tblaxland, was designed to rely on aerobraking on its return to Earth, as is seen in the next pic.

Notice how from the bottom, everything above is in the shadow of the heat shield. It's made designing both exterior and interior components rather challenging.

Here the two engines are seen, along with the deployable satellite dish, cicular solar panels, and stowed radiators. RCS units are placed at the top of the landing leg bays. The geodesic dome, and exoskeleton tube frames are at the core of attempting "something completely different" as is drawing from the living tortoise for design inspiration. There's just something elegantly ironic about the Tortoise blazing across the sky like a meteor.

Redesigns at this stage (though not shown in this earlier incarnation) are making both the docking port and cargo bays considerably bigger. The extending docking bay (like a tortoise neck) is now compatible with the DG. Similarly the side cargo door is large enough for Universal Cargo should anyone be inspired to ever implement it.

The bottom floor has been modified to take 2 - 2m H202 cylinders and a 1x2 m kerosene tank, plus 2 helium filled spheres to pressurize the engines (drawing from the Beal BA-44). Total fuel capacity is now at 20755 kg., which is plenty for Lunar orbit insertion, circularization, and return to Earth. It has, however, really cut back on cargo capacity.

Tortoise Lunar Capsule:

Bottom floor - 8.81 m dia. (28.9 ft. dia.)
Top floor - 7.37 m dia. (24.18 ft. dia.)
dome height - 5 m (16.4 ft.)

To facilitate use of the Tortoise without a Lunar Rotovator, a JV operation between Titan Werks Inc. and ZTC has resulted in the creation of the TLC-Lamprey system.

At first glance, the fuel tanks seem excessively over-sized. While the total volume possible here is approx. 84 m^3 (H202/Kerosene = 114641 kg.), it's not necessary to fill them to capacity. Titan Werks played a trump card with this configuration, and demanded the over-sized tanks in the event that an unforeseen mission might require them.

What makes the ZTC people especially nervous is the reduced clearance in the Tortoise's landing configuration.

Having just discovered LTMFD (today), I think I'm in for some heavy orbital experimentation before I have anything ready to release. However, any comments, suggestions, concerns tossed my way will be greatly appreciated.

 

[Grover]

that looks spectacular! but im a little confused, does a fortress act like a lunar lander? or is is more like a whole craft?

-==EDIT=--
ah, at second glance, i see that its a kind of CM and LM rolled into one, with a monstrous yet efficient descent stage (although the landing gear is contained on the ascent stage)

it truly is spectacular, but what is the dV (roughly) of such a craft? i presume it uses the LV final stage(s) to reach translunar trajectory? them performs LOI, descent, ascent and TEI using its own engines... or is there a new surprise in that it has a completley new lunar mission template

 

[Cras]

I second that. This project looks great.

And LTMFD really is great isnt it? I had it for a while but just never got around to using it. Then I tried it and it is amazing how accurate the thing is.

 

[n0mad23]

The descent stage is the kludge/work-around here, as the original design only had rockets used for course correction. The Ananke Tether-Sling provided the dV from LEO to the Moon, and there a companion to the Ananke (the Kronos) acting as a Rotovator would place the Tortoise directly onto the Lunar surface. At a scheduled time in the future the Rotovator would pick it up again and toss it back to Earth.

This is why the landing legs are on the ascent stage. It's really designed to be a multi-purpose Lunar Lander and an major component of the ZTC Ciclunar tether-sling transport system.

It might look like a fortress, but it's surprisingly light due to its geodesic dome structure and use of a tubular frame support system. Much of the structural strength comes from the catcher-tower that acts as a spine through the middle of the dome (and where a ladder and hatch to the upper deck are located).

I'm actually bouncing around between the modeling process and doing hypothetical tests (by changing the draft TLC versions configuration file) to figure out some of the dV challenges this "work-around" version creates. As I'm not a C++ programmer, I'm also looking at the various ways I can make this work as an SC3 vehicle. I'm guessing that the best working version will require using Universal Cargo Decks as the interface between the Tortoise and Lamprey Descent Stage. After my last couple projects, I'm really not so keen on attaching these two vehicles with the Payload function.

Because the two components allow a degree of mission flexibility, I'll probably end up with several vastly different Lunar mission templates. For example, one possibility is parking the Lamprey in a LLO and having the Ananke toss the Tortoise out to the Moon for a rendezvous and then use the Lamprey for everything right up to going back to LLO and creating a circular orbit. The Tortoise should have just enough fuel left to make it back to Earth and achieve a parking orbit after doing aerobrake maneuvers.

If the dV requirements are low enough for a particular mission, it's also conceivable that the Lamprey could be attached to the Tortoise in LEO and have the Ananke toss the entire assembly towards the Moon as well. Depending on the overall weight of this configuration, it's possible that the Lamprey could provide the extra dV needed to make up for lower dV the Ananke release will have (the Ananke was designed to toss payloads with the Delta-G's mass). The Lamprey can then be parked in a Lunar orbit when the Tortoise returns home.

With the possibility of loading the Lamprey up with a maximum of 114641 kg. of fuel (the rockets at this point are modeled after Notional Black Horse engines), I'm guessing that it's actually possible to take the two from LEO to the Moon using the Lamprey's engines alone. But this is entirely a guess as I haven't done the math to see if it's possible.

Here's the link to the Ananke at OH in case anyone wants to see what this has evolved from - [ame="http://www.orbithangar.com/searchid.php?ID=3399"]http://www.orbithangar.com/searchid.php?ID=3399[/ame]

 

[Grover]

you can always use the dV equation to work out how much you need, its what i do, but you need to be adept at algebra if you have vessel stacks and changing dry masses (like releasing a descent stage)

 

[n0mad23]

I'm assembling the Tortoise from its foundations up. I thought it would be best if I approached it this way, as it'll allow me both to fine tune my calculations for the capsule's mass and make sure all the pieces fit together perfectly as well.

In the following picture most of the major structural elements can be seen. The truss-spine serves as the element housing the connection allowing "intercept" (in quotes as we never actually solved that) with the Ananke. Additionally, the spine is used as the passage between the bottom and top floors, and both the deck hatch and ladder (mostly for lunar gravity) can be seen. The spine and beams for the landing legs provide the majority of the support for the upper deck. Some load bearing walls will also go onto the bottom floor - but see the end of this post for questions I have about this. The tubular framing surrounding the entire upper platform is mostly used to give the geodesic dome additional strength to deal with the forces envisioned with the eventual rotovator landing.

The following shot is from above to show the sizes of the decks in relation to each other. The top floor is broken up into several different sections, including the cockpit, two crew quarters, and a bathroom/shower room set between the cockpit and one of the crews quarters. Even with these rooms, about 1/2 of the floor is open common space and is also used as the kitchen. I'll post pictures of the room layouts soon.

I've managed to squeeze in "crawl spaces" beneath each of the floors which holds as much of the electrical and environmental systems (not the primary elements, but the connections and other things that don't need open easy access. Nevertheless, I'm finding the interior space dwindling fast.

The question I currently have in terms of the actual modeling as largely to do with the bottom floor and the additional walls. Following the advice in other thread and the way I generally do things, I've created and positioned my fuel tanks (both propellant and oxidizer) and some crude elements like life support, electrical breakers, HVAC systems, etc. If the Tortoise didn't have cargo-bay doors (requiring pumping the air out of the bottom deck before opeing) I wouldn't bother incorporating any of these elements into the model. However, many will be visible if looking through the open cargo-bay doors. In the interest of usability, should I replace most of these elements with walls in the final model? Certainly it would decrease the poly-count in something that's inevitably going to be rather excessive?

As usual, any advice, comments, or criticisms greatly welcome.

 

[Wishbone]

Wouldn't worry about extra walls - yet. Perfecting inner layout is fun, and it wouldn't do to forego all this fun too early.

 

[Grover]

ill be doing a construction management degree soon, perhaps we'll do loading first and i can offer some guidance based on what i learn at uni

other than that, its looking mighty fine indeed!

 

[n0mad23]

More internal elements have been added both for weight calculations and for space considerations. Most will be removed and replaced with walls, but at least I'll know it actually fits. No unobtainium in site....

The fuel tanks are about 3x bigger in this intermediate version than will be used in the final cislunar tether-sling version. I've gone with kerosene/H202 for a couple reasons (I'm sure some will raise their noses), and added spherical tanks for pressurized helium. Following the Beal BA-44, the addition of the helium boosts the thrust by about 30%. Some of the piping passes through the H2O2 tanks, and the rest utilizes the crawl space under the lower floor. Floor panels are removable for access.

The engines are now drafted out and I'll play with the piping some more before replacing them with the bulkhead and covering the rest with the geodesic dome.

The air-lock/extending docking neck is also drafted out, and it's seen here in its stowed configuration. It's a tight space, but using the NASA 3ds MKIII EVA suit model, an astronaut can fit inside. The bottom floor can remain pressurized while the crew do EVAs.

----Addition

I've removed the "hidden" elements from the bottom floor and installed walls to block the view (and house the units). Where the interior will be visible through the side cargo-bay doors (the "missing" two triangles in this shot), the current cargo-bay and access hatch can be seen. Focusing on creating a dedicated intermediate cargo bay was a good choice, and there's a bit more volume here than I'd thought there would be.

I've begun laying out the top floor, as well, and have stayed with my original plans here. As seen in the following, there are two crews' quarters, a lavatory, and cockpit. The open common area will house the kitchen and feature fold-out tables, etc.

It seems to be coming together!

 

[n0mad23]

I'm finishing up the last of the draft interior layouts. It's funny how many things tend to get overlooked from the notebooks during the modeling process (at least by me), and how many thing need to be rethought as well.

The truss-spine has been remade using tubes and retaining triangular structural support. I've also added extra bracing at its base to compensate for the needed open areas to allow easy access by crew, as it houses the connection between decks. The "foyer" zone between the spine and docking neck has mostly been filled by stores for food and other crew necessities. If additional stores are needed, nearly 1/3 of the bottom deck remains for cargo space.

The upper deck's kitchen/common area is drafted out. A fold-out table is attached to the truss-spine and several sets of fold out chairs are attached to available walls. Mounting things to the dome's walls has proven a lot more challenging, and I've been creating a lot of temporary files to whack away all the dome except for the area I'm working with. It has proven to be a really useful use of the space that's mostly inaccessible due to low clearance.

For lunar work, the Tortoise is designed to house 6 to 8. Two folding wall mounted bunks are in each of the crews' quarters, and 2 sets of hammocks mounted on tracks are in each of these rooms as well. The lavatory has a dual use toilet (both free-fall and lunar gravity configurable) and an enclosed low-flow shower. The HVAC and water recycling systems are conveniently located nearly directly below next to the landing leg alcove.

Now I'll turn to the cockpit (mostly done from the proto-draft), and focus on getting it assembled in its entirety for some kind of working draft. There's a lot of really complicated animations required here, and I'm already trying to figure out ways to make it easier. For example, exporting everything BUT the interior to work out the landing legs and leg-bay door animations to remove all the unnecessary mesh clutter to make seeing a bit easier. Then go back to the final using the same animation sets with corrected mesh groups.

I have got a early working draft of the Tortoise-Lamprey up and running. Here's a couple of pictures of it's flight from LEO (about 400 km initially) to a lunar parking orbit. In the second picture, the blast plates (protecting the fuel tanks) also double as solar shields. I'm not quite sure of the refueling needed here and how that's going to work. But for now I can use Scenario Editor and know that it's waiting for a draft Tortoise!

 

[Mandella]

I love the look of this thing.

Unusual, but realistic craft FTW!

:thumbup:

 

[Grover]

good to see it (or at least a small part of it) in the sim!

if you send me some mass figures, i can calculate how much fuel you need if thats what you meant by:

I'm not quite sure of the refueling needed here and how that's going to work.

but i can work with the numbers if you have an idea of the dry mass of each "stage". and because theres no atmosphere on the moon, i can work out fuel needed for the ascent as well converting GPE to KE to fuel and adding it on, then compensating for it

ok, so its a mathematical minefield, but its possible to calculate using just MS calculator, a sheet of A4 and a pencil (old skool style )

laters man! and keep up the awesome work!

 

[n0mad23]

The Tortoise continues to come together, and the texturing is going at a snail's pace. But for verisimilitude, I'll add textures with a toothpick.

If you send me some mass figures, i can calculate how much fuel you need if thats what you meant by:

No, I meant about resupplying the Lamprey module's fuel supply as it does its lunar parking orbit between Tortoise landings. However, I'd love to send you my figures as I've always suffered a form of numerical dyslexia and having another brain to check my sums is always a great idea! Thank you! I'll try to have a rough set out to you before I head to bed tonight. I'm actually digging through the DOD Composite Materials Handbooks (links posted on the Space PFD thread) between modeling sessions crunching numbers based on ongoing research there.

Most of the Tortoise's components are lifted into orbit and assembled outside the Titan Werks LEO "wet" workshop. The wet-workshop is also a R&D site where both Titan Werks and ZTC have been experimenting with vacuum vapor deposition and recycling some of the dead satellites that ZTC has grabbed. In other words, some of the framing for both the Tortoise and the Lamprey are using some experimental materials, including titanium foam metal alloys. Getting the numbers right is proving to be a case of "informed guess-work" but I'm hoping to get a bit more accuracy. I'm really trying to keep the Tortoise at around the same empty weight as the stock DG, but I'm beginning to suspect it'll be a few metric tonnes heavier. The Lamprey, on the other hand, is going to be really light. Foam metal alloys will account for the greatest single mass, followed by engine components, then fuel tanks, and hollow tubes.

The original "artist rendition" of the Tortoise attached to the Lamprey with Universal Cargo Decks, out for a test drive from Titan Werks - ZTC's wet workshop.

I did a couple of test flights last night using the Ananke Tether-Sling to toss the Lamprey out to the Moon, and it looks like the Ananke's the most viable way to get this module to where it needs to go. Though it exceeds the intended payload mass for the tether-sling (by about 4x's), the Ananke's superior mass does indeed impart a descent dV to the Lamprey. Using IMFD and TransX in conjunction, I was able to get a vector putting me 23 km over the Moon using less than 3% of the Lamprey's fuel supply. After doing an orbital capture and subsequent orbital cirularization, more than 90% of the fuel remains!

 

[MaverickSawyer]

Looks nice!

 

[Grover]

just had a thought about the Lamprey

youre gonna have to add some sort of computer system, and possibly communications equipment aboard it if its going to get to the moon alone. at least a computer to control the vital course corrections, and possibly communications equipment to allow the engineers/pilots to control it in any event necessaryu

 

[n0mad23]

Agreed. My Anim8or time last night actually was partially spent doing a couple of possible layouts to incorporate this.

I'm actually thinking that after the Tortoise docks with the Lamprey that control should probably be handled with the same system, or possibly by adding a WiFi network that bridges the computer on the Tortoise with the Lamprey's. It makes more sense than adding a hardwired system that needs to physically plug into the Tortoise.

I think the Lamprey needs a solar panel or two to meet its electricity needs as well.

I'm currently reading the NASA doc "Preliminary Assessment of Artificial Gravity Impacts to Deep-Space Vehicle Design" and finding a lot of really useful data for nailing down the masses required in a lot of this. The best news is I've really over-estimated the mass of the Tortoise. For example, I was thinking a CO2 scrubber would probably weigh about 350 to 400 kg, but the Sabatier CO2 Reduction Unit able to sustain a 6 person crew for 18 months only weighs 26 kg. This is one of the more drastic over-estimates I made, but I am finding that my guestimates are consistently this way. This document is linked in the Space PDF thread here.

Thanks for your assistance with this Grover. If you like, you'll be the first to get an Alpha copy for testing!

 

[Grover]

id be happy to help further, as long as uni work doesn't stack up, ill be on it

 

[n0mad23]

Pretty pictures time

I do believe the modeling of the Lamprey is done. I've added computers/guidance/communications as well as all the necessary RCS and Linear thrusters. The animations are all but complete (I need to play around with the timing a bit more).

I've been doing this project as a way of inspiration for doing the beginning of a novel (the middle and end are already finished), and find that it's really been fruitful. The latest big surprise for me is how much the Lamprey looks like some kind of Steam-Punk Tortoise Totem. I've already written a scene where one sails overhead of Tortoise astronauts on an EVA near Malapert C. Archetypes underlying the forms.

The stowable solar panel animations are done with shift-1 and the communication dish is done with shift-2.

The solar panel is shielded from the rockets on lunar ascent.

Now I'm turning to fine tuning its mass issues, and trying to finish up the remaining Tortoise construction.

 

[K_Jameson]

a very, very strange design!

 

[MaverickSawyer]

Just because it's strange doesn't mean it won't work. After all, when designed properly, form follows function.
I think that it is a beautifully simple design, ideal for it's task.