Challenge of the Highest Order: The Grand Tour

[Captain Sierra]

Yep! I have a burning desire to see that shiny new Grand Tour Shield on my ribbons complete one of the biggest challenges KSP has to offer.

So, no point dilly dallying, let's get straight into it!

Part 1: Architecture

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For the mission, I've developed a new grand tour module craft, once again modular, as most of my megaships are.

Below is an image of the new Sentari class tour ship. Even with my GravMax Tylo lander on the rear, it has over 6.8km/s of delta V.

Now, this is of course hyperedited to orbit purely for some testing purposes. The hitchhiker and docking port pieces seem to be weak and are causing a lot of wiggle as the majority of the torque is at the front near the CoM, AKA pile of fuel. In this configuration, it has 7 orange jumbo tanks for fuel, plus a little more in the docking assembly Fuel flow still needs testing to ensure that works correctly. It's powered by 12 stock nuclear engines. The housing module at the rear boasts capacity for 12 kerbals, though I plan on taking no more than 6 (yes, I did consider using one of Porkjet's habitats). The ship is easily reconfigurable. Even the bridge doubles as an RCS powered runabout and has a special bay in the rear for when the craft is aerobraking (because the giant heat shield is just good roleplay ; and yes, it's welded so my part count is tolerable) as seen in this image, which is of a slightly older version. You may notice the use of stock solar panels as opposed to the badass ones in NFP.

The first one constructed is to be named the Nebulon. It will carry a small RCS tug for reorganizing the craft if necessary as well as two SSTOs for atmospheric planets (except the black hole, AKA Eve) and two kethane refueling landers. While it's possible to refuel from Kerbin, as well as pack all the fuel you'd need (insanely difficult; please show me a successful mission doing this, I know of none), my mission will be kethane powered. That said, the requirements on the ketholanders are pretty high as they must be able to take off from the surface (fully fueled), unload raw kethane to be converted on board the Nebulon, and then go back down and land without refuelling off the Nebulong (or else this would take forever). On top of that, they need to be able to land on lot's of planets, from Ike to Eeloo to Moho to Minmus. They will be one of the more challenging aspects of this mission, not to mention the tedium of the dozen or so flights to fully fuel the behemoth.

For one of the hard legs, I have developed this Tylo lander, the GravMax.

The upper stage has asparagus drop tanks while the lower stage has onion drop tanks with 48-7S engines on the bottom for better TWR while landing. It has just under 7.5km/s delta V, is pure chemical (so no irradiating potential surface samples), and has a consistent TWR over 1.5. The upper stage features the flattest 2.5m tank and 4 48-7S engines. These give it the delta V to land and take off pretty much anywhere. Now, it does not have parachutes to do atmospheric landings, as those are unusually heavy and shave almost 600 dV off, which is unacceptable. The SSTOs will be relegated to atmospheric landings.

Mission Profile:

So the mission profile is this. First, the Nebulon will run out to Jool. The GravMax Tylo lander upper stage has the TWR and dV to land on every non atmospheric body including the ever-tricky Vall. We'll top off with the ketholanders at Pol and then head back inward to Duna. The spaceplanes can handle an unpowered Duna descent and should be able to take back off on rockets alone. The Nebulon will be in a high orbit of 125-150km after aerobrake for that. After a successful Duna landing, the GravMax will be dispatched to Ike. With just over 2km/s dV in the upper stage, it should have no trouble.

Following that, I'm still debating where to go next. Eve was a target, but I am unsure if I want to tackle a challenge that hard this early in the tour. Unlike the GravMax, which has practical use after the Tylo landing, the Eve lander will likely be a one-time-use craft. Either way, time will tell on that.

I'm open to suggestions. The second post will be reserved for the segment of this on the construction of the Nebulon.

[Captain Sierra]

Part 2: Assembly

While many aspects of the actual utility section of the craft remain undetermined, the primary propulsion stage is a certainty. The drive stage was launched today into a 250km assembly orbit. Powered by twelve nuclear engines and fueled by a minimum of seven orange jumbo tanks, this thing will have immense delta V capacity. Preliminay maths indicate upwards of 6500m/s even with full payload including a Tylo certified GravMax lander.

The launcher was a 4 booster parallel staged launch vehicle with clustered engines. Each booster delivered 1490kN of thrust while the center stack powered out 2520kN, placing the drive stage in orbit with an RCS fueled Monotug. The tug will allow quick and sloppy docking of the fuel modules, simply to get the up there, and for more precise docking to be carried out later, in between tank arrivals.

Below is an included album of the next part, the heat shield. This will protect the craft during aerobraking maneuvers. After that, the fuel tank launches will commence. The lifter for the empty tanks has yet to be designed at this time.

Javascript is disabled. View full album

Edited January 29, 2014 by Captain Sierra

[Duxwing]

How will you across the vast void haul your Eve lander, which will need hundreds of tons of fuel and engines to overcome Eve's immense gravity and high, crushing atmosphere?

-Duxwing

[Captain Sierra]

How will you across the vast void haul your Eve lander, which will need hundreds of tons of fuel and engines to overcome Eve's immense gravity and high, crushing atmosphere?

-Duxwing

The Eve lander is going to be sent separately to rendezvous with the main craft in Eve orbit. It will be sent out on an unmanned transfer stage. The Tylo lander will remain useful long after the Tylo ascent so it will be kept. I doubt the Eve lander will share such a trait as it will probably be single use.

As for the GravMax, it will ride along on the rear. I'm busily HyperEdit testing it now. So far, the dV is there, but it seems to have difficulties with torque control, not enough of it. It doesn't like to turn when the engines are off and that creates some difficulties preventing crash landings even though I can get it slow enough.

[Captain Sierra]

-bump-

The beginnings of part 2 have been added to the second post. Just giving it a quick status update.

[Duxwing]

I now understand your design. Thanks.

-Duxwing

[ramnrmeul]

I think you should bring the Eve lander to Eve with only the fuel needed to get to is destination and fill it with fuel when the Grand Tour ship arrives.

[Captain Sierra]

I think you should bring the Eve lander to Eve with only the fuel needed to get to is destination and fill it with fuel when the Grand Tour ship arrives.

I'll definitely experiment with sending the Eve lander empty. I'm concerned about fueling it back up though, since eve landers are a spiderweb of tanks. I'd also be concerned since it has about four and three quarters worth of orange tanks. The Nebulon is only slated to have 7, MAYBE 8 in a heavy configuration (the 8 configuration could support up to 14, but then you start reaching the point of diminishing returns). I'll have to do some dV math on that, definitely. It'd certainly save me a good bit on the transfer stage for the lander from kerbin to do that.

[StevenLawyer]

Here's my single launch, no refuel, stock grand tour ship that includes a reusable lander for all planets except Eve (Eve is a separate one time use lander), including Tylo with reusable rover and reusable probes (you're not going to land on a planet without first sending an unmanned probe, are you?). I finished the mission with fuel to spare.