Who Needs Command Seats? a minimalist Grand Tour. *IT IS FINISHED*

[immelman]

I've been looking at this on and off for a couple of months now and thought it would be good to post my planning as it progresses.

First three artificial limitations:

1. No Command chairs, Jeb must travel too and land on all Kerbol's (where it is possible, so no Jool!) bodies in at least a lander can. This significantly increases the total mass of the mission.

2. Try and do this with the least mass on the landing pad possible, under 100 tonnes If I can.

3. No funny business with cubic struts, or weightless aircraft landing gear, so none of this for example:

Which is a shame! It would make it a lot easier. But if I need to attach a part cubic struts are fair game.

Mechjeb or not Mechjeb, that is the question: while I frankly don't understand some of the attitude against this tool, it's going to be fun seeing how I get on without it. With one exception, to keep the weight down we will be using this to taxi Jeb around the Kerbol system and looking at the 40 minute to 90 minute burns this is one place mechjeb stays!

Edited May 9, 2014 by immelman

[immelman]

Ah Eve, this is where it can go all wrong. We need to shrink down the Eve lander as much a possible.

My first Eve lander was an almost 60 tonne monstrosity:

I know the higher you go the lower the delta V requirements, so I've looked at fitting wheels to the lander and driving up the highest mountain in the game, or gliding to it (which works surprisingly well):

But in the end if NASA can land a probe on Mars in a 1km x 1km box, then why can't I!

So flying pancakes it is (so they don't flip over when landing on mountain sides).

I've gone from this, which at 45 tonnes is still too big:

To 36 tonnes:

To what I hope is the final design at 28 tonnes:

Now I just have to land it above 6500m...

Edited March 21, 2014 by immelman

[Tw1]

But in the end if NASA can land a probe on Mars in a 1km x 1km box,

At first I thought, NASA has never launched anything that big, then I realised you meant square, and where talking about the target area...

Nice job halving the weight of the Eve lander. Are the sepratrons vital, or could you shave some more?

[immelman]

At first I thought, NASA has never launched anything that big, then I realised you meant square, and where talking about the target area...

Nice job halving the weight of the Eve lander. Are the sepratrons vital, or could you shave some more?

Looks like I can, without the septratons the decoupled parachutes would stay on the lander and tip it over during flight. So put the parachutes on the side! Also with removing some unneeded engines and shifting fuel around we are down to 24 tonnes:

I've had Jeb give it a dry run and it will get into orbit with 31 units of fuel left. It looks like an EVA to circularize will be necessary on the big day:

[Speeding Mullet]

That's a very pleasing Eve lander, I still have not tackled that particular challenge. Looking forward to seeing how this mission shapes up as it looks like I could learn some serious ship shrinking techniques from you.

[immelman]

I think that is the Eve lander finalised, though a pinpoint landing on top of Eve's tallest mountain is called for.

Two things I've checked out:

1. Using a very small light drone to act as a pathfinder for the landing.

2. How important is the gravity turn? I've launched the lander with a turn at 23,25,27,29 and 31 km. It looks like that 29km is the best height, but the difference is only 53m/s!

What is more important is how flat is the bit you land on, if like me you land on a pretty steep slope, it takes quite a bit of fuel to straighten you up...

There is a Western shoulder to Eve's tallest mountain that's pretty flat, should aim for that.

Since I plan to lift from Eve last, next is the lander of Gilly, Mun, Minmus and back to Kerbin. The fuel I need will tell me how much I need for the Eve transfer vehicle.

Edited March 23, 2014 by immelman

[immelman]

That's a very pleasing Eve lander, I still have not tackled that particular challenge. Looking forward to seeing how this mission shapes up as it looks like I could learn some serious ship shrinking techniques from you.

Thank you! I have to admit, it's building the stack I'm most concerned about. The part count is going to make my PC lie down on the floor and cry...

Edited March 23, 2014 by immelman

[immelman]

After playing around with a couple of configs I think I have this settled, one third of the grand tour planning done!

I had a look at using the LV-N on the Eve transfer vehicle as the main engine for this and not refuelling, but the mass of the lander is so small that I ended up with less overall Delta V. Plus landing on the engine bell was hard, only managed it once out of three tries on the Mun!

Here is a very handy series of charts for working out this done by Tavert: http://imgur.com/a/iNqmQ#0

So here is the lander with attached lander can, it has about 200 more Delta V then I needed to transfer to Gilly, land and then transfer to Kerbin, that will be my reserve:

I'll aero-brake into a Mun passing orbit and refuel there with this, there is about .2 of a tonne more than I need here, but I'm worried about part counts as well, so leave it as this for now:

And back to Kerbin, don’t need a parachute, we will just land as is:

[immelman]

As a sanity test and to keep track of the mission mass so far I'm stacking the units together.

This mass includes circularising the stack in Kerbin orbit, transfer and landing of the Eve stage, transfer and landing on Gilly, Mun and Minmus and Back to Kerbin. 37 Tonnes so far:

Edited March 23, 2014 by immelman

[immelman]

Hmmm, Just been reading that the lv-1 and ion engine my be increased in the coming update. That will change things.

[immelman]

I've done more shaving, as long as I land on Eve's highest point and with an EVA this will get to orbit at 20.1 T:

[Speeding Mullet]

.....The part count is going to make my PC lie down on the floor and cry...

Haha I know the feeling. I just sent an 894 part leviathan to do the Jool 5!

Can't believe you got moar shaving out of the Eve lander, this is shaping up nicely.

[immelman]

Now I've got Eve out of the way for sure (I think!) It's time to look at the Jool section.

Laythe:

Tylo (where I'm going to use the transfer stage to help land)

Vall:

All these have been tested. Bop I plan to use ION drives and Pol, well I'm going to wait and see about the latest update to the game.

Time to put the Jool stack together methinks.

[immelman]

I've been playing around a lot with the KSP Trajectory Optimization Tool:

http://forum.kerbalspaceprogram.com/threads/36476-WIN-KSP-Trajectory-Optimization-Tool-v0-11-2-Mission-Architect-Pre-release-1

Mainly because I need to minimize my Moho, Dres and Eeloo Delta V.

With Moho of course it's always the insertion Delta V, even using this tool some of the results you got demanded a 3000m/s deltaV insertion burn, ouch, we can't have that.

Using the tool I've worked out a slingshot via Eve which puts the craft into a Moho passing orbit on it's inclination and on the periapsis and ascending node, which means the craft gets into a 0 inclination 200Km orbit for less than 3000m/s total:

I'm pretty pleased about this!

So here is the ion powered shuttle that will transport the Moho lander as well as the 1400 m/s in extra fuel to transfer to Eve, using ions makes the ship half what it would be otherwise. I'm looking forward to the greater thrust for ion drives in the next update!

[immelman]

After real life intervened I had a good look at the updated engines, especially the IONs.

Which led to me throwing away my landers for Mun, Minmus, Eeloo, Bop, Dres and Ike! I'm going to use ION's to land on them now.

Anyway here is the final craft, 75 Tonnes:

The mission plan is to use to two bigger ion powered tugs to move landers and Jeb around the system and two smaller refuel pods, one for Dres and one that stays in orbit around the Mun.

Jeb will land in order:

Eeloo

Laythe

Val

Tylo

Bop

Pol

Dres

Duna

Ike

Minmus

Mun

Moho

Eve

Gilly

Kerbin

I hope it works out, the fuel budget is pretty tight in places...

Edited April 24, 2014 by immelman

[immelman]

And we are off! Nine turbojets are enough to lift off, one of which I will keep as the Laythe lander. It's a very complex craft with 751 parts and needs a lot of rearranging in LKO to assemble the various components. With all the intake spamming it was not that hard to get it to a 99K AP. A useful trick is to place your last turbojet in the centre of the craft, that way it will flame out first without creating a death spin, warning you when to reduce thrust.

I starting turning the craft at 10000m, aiming to be horizontal at 32000m where I accelerated to orbital speed and pushed my AP above 100Km:

The turbojets were ditched at 59km:

The circularising burn was only 51 m/s:

With another 47m/s to correct my inclination:

Edited April 24, 2014 by immelman

[immelman]

First task is to get the ION craft undocked and safely away from the mothership. Here you can see the bigger 2 drive craft below the mothership with one of the single drive refuel vessels above.

The two nuke engines will push the Eve lander and Jool stack.

Next off is the parachute for my Kerbin return, which will stay in LKO and the lander can still attached to the Moho lander:

[immelman]

Two ion engines do not give enough TWR for Mun and Eeloo, so they have an additional ion drive docked underneath, here you can see it coming into dock with the Eeloo lander:

The completed Eeloo craft/lander. It is heading there via a Eve/Kerbin/Kerbin/Jool slingshot:

And the Duna lander docking with the ion taxi which will transport it to Duna, return, refuel and head off with another lander for Moho:

[meve12]

Those look awfully small for landers.

[immelman]

Those look awfully small for landers.

It should be enough, we'll see if I'm right!

[immelman]

Next to assemble was the Jool and Eve stack. to do this I undocked the turbojet which will also serve as the Laythe lander:

And the two nuke engines, which are now going to power the two stacks:

Resulting in the two craft ready to go:

I'm also going to keep track of the rocket fuel used, for the section to circularise and adjust inclination I had 22 units spare, which is about 1/4 of a ton, not bad...

[technion]

Tylo (where I'm going to use the transfer stage to help land)

When you've got so little fuel, is the nuclear engine really the most efficient?

I just built a demo with KRE and a lander can, no other parts. If I place an FL-T100 and an LV-N, it's good for 1,220dv. Swapping that for a 47-8S, it's good for 1,631dv. With an FL-T400, the LV-N is good for 3,848 whereas the 47-8S gets 3,749. It's an improvement at that point, but is it worth dragging all the extra dead weight the whole way to a low Tylo orbit? I've been trying to work this out myself on my Tylo lander.

[immelman]

When you've got so little fuel, is the nuclear engine really the most efficient?

I just built a demo with KRE and a lander can, no other parts. If I place an FL-T100 and an LV-N, it's good for 1,220dv. Swapping that for a 47-8S, it's good for 1,631dv. With an FL-T400, the LV-N is good for 3,848 whereas the 47-8S gets 3,749. It's an improvement at that point, but is it worth dragging all the extra dead weight the whole way to a low Tylo orbit? I've been trying to work this out myself on my Tylo lander.

Thats a good one! in addition to: http://imgur.com/a/iNqmQ#0 let me show you how I approached this.

Here is a lander using three 47-8s and 8X50 tanks in asparagus which will (just) get down Tylo and back up:

And here is the same set-up with the additional fuel to get down to LTO a mass of 9.8T:

Now here is the same set-up with the Nuke 9.1T:

BUT the nuke by Tylo orbit is "free" I've already paid the fuel to get it there, so if we look at the fuel needed to get down to LTO, land and back up again it is 6.9T.

In other words using the nuke saves almost 3T plus the mass of fuel to get to Jool:

It's the better choice (I think) even though in landing the lower TWR means it needs more Delta V to get down, it is so much more efficient that it still beats the 3 47-8S setup...

Edited April 18, 2014 by immelman

[technion]

I like the layout there - I think I'll be reevaluating my landers.

[NecroBones]

Wow, this is very cool. I can't imagine operating on such small fuel quantities.