Grand tour 2, Jeb's revenge.

[magnemoe]

After Genebree managed to do an grand tour with an 233 ton ship, Jeb was envious and wanted to do better.

Looking at details of the grand tour he found multiple things who could be done better.

First an lighter Eve lander.

Lander during an ladder test. Uses 9 48-7S engines in asparagus, mostly 45 liter fuel tanks, balanced to keep ISP constant.

The two 90 liter tanks with the braking parachutes are mostly for deorbit however rest fuel will be used during accent.

Use ladders instead of seats to save weight.

Lander on pad with dV and info.

Someone has managed to make an even smaller one but I prefer an extra margin.

I also looked at the Tylo lander, the old one was using the 3300 m/s lander as upper stage with an lander stage with an 360 liter fuel tank and two 909 engines, had two 180 liter drop tanks for deorbit and part of braking. making it an 10 ton part.

Found that I could use parts from the Eve lander and got an 2.6 ton part.

Upper stage with ant and oscar has 1250 m/s dV but dont show up in the dV table.

The upper docking port is if i want to transport both the Tylo lander and the main lander at once. might also be used for an extra fuel tank if I want to do deorbit from high orbit.

[magnemoe]

The main lander, pretty much like the old lander but it uses two 48-7S instead of the radial 24-77, as the 48 has far better ISP it increases dV from 3300 m/s to 4000.

This will be used everywhere except Eve an Tylo, might use an additional docking tank for Laythe deorbit and braking.

[magnemoe]

Putting it all together.

Ship on pad is 935 ton. This mission would be launched as one part without adding parts or topping up fuel in LKO.

12 mainsails in asparagus, surprisingly stable for an so large construction.

Dropping the last of the outer six engines after gravity turn.

In orbit, 156 ton, its heavier than I expected, probably because of the 8 drop tanks with 360 liter fuel each, probably overkill as they Tylo and Eve lander is so much smaller. The drop tanks require manual fuel transfeer and don't show up on the dV stats.

In front is the Eve lander, followed by 7 tanks of 90 liter who will be used going to Moho.

At the downside the upper stage who will be uses going alone to Moho, Dress, Val and continue after Tylo.

This is smaller than the previous version so it will need the extra fuel for going to Moho.

At top the Tylo and reuseable lander. in front of them is an 270 liter docking tank who is also used for balancing so I will move it to the other side after decopling the second stage. two 90 liter docking tanks under the landers, nice to have and I needed to move the landers away from the drop tanks.

Below the Moho tanks is an small tank with engines and probe designed to do refueling at Laythe.

[magnemoe]

First Mun and Minmus.

An last chance to test the main lander. The Mun landing had an problem, an ellipse caused me to run out of electricity making it impossible to turn the lander. However an less optimal burn put me into an orbit and I was able to circulate and land.

Then off to Eve, here I'm dropping the two large drop tanks. One small was dropped in orbit, it was used circulating and fueling the lander going to Mun and Minmus.

The trip to Eve cost me, around 1500 m/s dV, not optimal as I had to do some adjustments and the plane change was to close to Eve, of the total 10641 liter fuel I started with I have 7282 liter left.

[magnemoe]

Eve landing, here the lander after deorbit burn.

Did this manual as Mechjeb auto lander tend to burn to late and wasting fuel to increase accuracy however +-500 meters was not an problem here.

I did not realize I could not do time warp on ladder. Had I know I would probably added an seat on the deorbit tank and put an probe core on the other to balance and give more torque.

Landing on parachutes only

Legs was very shaky, should probably have strutted the decoplers.

Back in orbit with plenty of fuel, had I had less I would just done an 105 km orbit an used the other lander to pick me up. Still had to use it as I didn't want to match up without warp.

[magnemoe]

Gilly is always fun, used the main lander, yes its a bit conter intuetive that going an long trip to Gilly at its Ap uses far less fuel than at Pe, its the circulation and plane change burn who is expensive and both are cheaper a long way from Eve, Might be cost effective to use the upper stage, but not fully fueled and I dropped all the empty tanks.

Off to Moho, as usual an expensive place to go to.

Here I'm dropping two of the 7 90 liters drop tanks,

Yes I hate Moho.

Going back with an interesting maneuver node

The plane change as part of the main burn was around 400 m/s doing it in solar orbit would cost 1200 m/s

Moho dV budget. 1360 m/s burn in Eve orbit, 1250 m/s plane change and 3410 m/s circulate, yes it was an bad one, problem is that Moho has an non circular orbit and if you don't intercept perfectly its expensive, another option is to first burn for solar orbit and then plan the Moho intercept, cost is pretty much the same unless you are very lucky around Eve.

Back was 2618 m/s with an 260 m/s adjust, 90 m/s in Eve SOI, docked with 50 m/s left.

An ion based Moho transfer stage with an disposable two stage lander might be an good idea, saves 1485 liter fuel or around 18 ton who is heavier than the Eve lander.

[The Destroyer]

Sounds good! Looking forward to more!

[magnemoe]

More is comming )

After comming back to Eve it was just an four day wait for the Duna window. Docking second stage fittingly on top of first stage, after starting the burn remember to turn off the second stage engine.

Burn to Duna was 1618 m/s, 333 for plane change and 75 m/s adjustment.

At Duna I separate first and second stage docking the lander and one of the 90 liter docking tanks to second stage.

On they way to Ike the first stage came into Ike SOI even if I checked the path before the second stage burn. It put the second stage on an impact path with Duna so I had to change it and did an small aerobrake who put it low enough to be safe.

Back-flip on Ike, yes Jeb ended on his face.

400 m/s from Duna to Tylo orbit, dropped the docking tank after Ike.

Now the first stage goes to Jool and Laythe.

As the first stage is in an pretty eccentric orbit, Pe at 100 km and Ap at 500.000 km and I was able to burn at Pe the transfeer just cost me 1045 m/s dV with an 107 m/s plane change.

Mechjeb2 has an nice function who let you get the cheapest path to intercept, does not always work but then it does its pretty much magic.

Just an tiny burn then entering Jool SOI and some rcs adjustments for an perfect intercept. Posible to do manual but it require serious precision.

As you come in very fast you better enter Laythe SOI close to the aerobrake node.

The flat tank in front is the Laythe resuply module or Laythe care package as Jeb has named it, it will areobrake down to low Laythe orbit and wait for second stage.

First stage waited in an eccentric orbit waiting for an good Tylo intercept and was able to get from Laythe to Tylo using just 170 m/s.

At this time second stage is in Solar orbit, did an 123 m/s burn to get out of Ike and Duna orbit, thought this would make it easier to get an good intercept and I was already almost at the SOI.

However I was unable to get any good Dress intercepts, 860 m/s burn, 375 m/s plane change and 1080 to circulate so it was an serious mess.

Still Jeb was able to plant the flag.

More mess to follow, I thought my Jool intercept was good and would make up for the Dress , 488 m/s and a 146 m/s plane change.

However I was looking at the resulting orbit around the sun after the Jool intercept, it required an Jool Pe of less than 0. Even Jeb found it was an bad idea, however it left me 45 degree out of the Jool plane.

Instead I did the fanciest maneuver I have done in KSP. Did an direct intercept with Laythe, however it put me pretty much in polar orbit so I did an non capture aerobrake around Laythe, it put my Ap outside Laythe, here I did the now pretty small plane change and then waited for an Laythe intercept, still the mess cost me 500 m/s dV but not sure it was more expensive than doing an plane change in solar orbit without any plane change nodes.

[magnemoe]

Finally at Laythe, a bit lower on fuel than I wanted so it was an relief to be able to dock with the Laythe care package, its an probe with two small engines for orbital work, 540 liter of fuel, 80 liter of monopropelant, it also has an 45 liter drop tank for the lander to help it with Laythe.

The Laythe resuply probe had no rcs trusters. I planned it to resupply second stage where I had just used 25 liters totally at Duna, Ike and Dress, but used 50 liter docking with the lander with the heavy probe in front, both me and mechjeb was equal hopeless and as the lander has docking port in bottom I could not do an non rcs docking.

Next time add trusters on it and disable the forward trusters on the second stage.

Dropping the drop tank before the Laythe landing.

I planned to drop it before final decent, however the decopler was pretty stupid I had to undock the docking port or it was to high for the landing legs.

Testing shows that undocking destabilizes the lander. This is probably as the lander changes "control from here" from the probe to the seat, it might also be because the lander is not very aerodynamic stable with all the struts and stuff at the bottom.

Jeb is unhappy as he landed to far from water, it has been an long time since he bathed last.

[magnemoe]

Val was easy, a 553 m/s burn from low Laythe orbit, had to do an adjustment of 67 m/s and circulate cost me 275 m/s.

The ladder on the lander was an good idea if its aligned correctly, the original design including a ladder going up from the command module however it was forgotten so I have to remember to align the parts so the ladder reach the hatch.

Tylo on the other hand is hard.

First I had to match up the first and second stage where the first is almost out of fuel and I need most of it for second stage.

270 m/s burn, an 32 m/s adjust and 620 m/s to circulate at 400 km who was pretty optimal attitude for first stage to.

As I had far to much monoprop left on first stage I used it to get into docking distance with second stage, I used a bit more fuel than planned, should have gone for an higher attitude.

Empty the first stage for fuel, top up monoprop and dock the Tylo lander to second stage, dock the main lander on top, luckily I added the top docking port as I have to go down to 100 km to use the tylo lander. Writing this while waiting for the lander to get into position for deorbit, uses an ladder instead of command seat so I can not warp, do not think I will do that again even if it saves weight.

[magnemoe]

Tylo landing, yes I had to reload, not an good idea to use aspargus on the landing part as trust dropped dramatically then first stage was empty.

It was also extremely boring not having warp.

The dismounting was as graceful as the rest of the Tylo opperation.

Worse Jeb ended halfway under the lander and I had to use an minute getting him out.

Finally I did not have enough fuel to get back into 100 km orbit but ended in 70x20 km so I had to use the main lander to pick up Jeb, 20 km is naturally below warp limit.

Continue with Pol then Bop and Eeloo, however this should not be any huge issues.

[The Destroyer]

Come on guys, comment!

[magnemoe]

Come on guys, comment!

Thanks, I have already started planing an third grand tour, main problem with current mission is that the first stage is totally overkill after Eve, and wasteful heavy after Duna.

Think it should be possible to take the grand tour with less than 100 ton from LKO.

[magnemoe]

After Tylo, Pol was relaxing, Jeb is jumping of joy, love the mountains on Pol.

760 m/s burn to get where, an 74 m/s adjust and 270 m/s circulate.

Next up is Bop, I wonder who Bop Kerman was? probably the one who discovered the moon however we don't have any Pop craters so its strange.

Strange texture bug, on it

Used 43 m/s to get into Jool orbit, 132 m/s on transfer, an embarrassing 23 m/s adjusting and 256 m/s circulating.

Landing and probably conclusion tomorrow.

[magnemoe]

Bop landing was undramatic, mechjeb landing autopilot even worked unlike on Pol, it has problem then the gravity is to low and this includes Bop with some landers.

Takeoff on the other hand was pretty dramatic. Second stage was in an almost polar orbit around Bop and the mechjeb launch looked like it fitted well, I did some minor changes to make the orbits align better and warped towards burn, luckily I saw that the orbits was retrograde just before the burns started, abort burn and try to modify the orbit so it fitted while I was falling back towards Bop.

Worked well enough, thinking about it I have run into this at Bop before, someone should put up an warning sign.

Final separation, after lander returned I moved the last 20 liter fuel from the side tanks to the lander and jettisoned them.

4000 m/s fuel left but it also includes fuel for Eeloo and not to forget Kerbin landing. Unlike the previous grand tour its no refuling and service probe in Kerbin orbit, yes I can launch one but it would void the grand tour.

13 years wait for an Eeloo intercept, I looked a bit to see if I could find anything faster but did not find anything fitting, I also has to think about the circulate burn, burning from Jool orbit gave an 5 year wait and no good intercept.

Jeb paid an hourly rate and don't mind waiting and I must go to the post office

Anyway the dV budget is an joke, it cost me 60 m/s from Bop to Jool orbit and 640 to sun orbit. will cost me 152 to intercept, 290 to match planes.

Edited August 21, 2013 by magnemoe

[magnemoe]

Yes the command module is small but its plenty of room on the outside.

Eeloo circulate was 559 m/s

Landing was without events but I cut the fuel for the lander a bit short.

Worse I did not notice before circulating, stupid as I have enough fuel.

Going back

landed and planting an flag to protest against the speedbumps who has destroyed so many rovers.

What next? Jeb migh retire, however he have heard about an new project, orion pulse detonation engines sounds fun.

Others want to beat him in the grand tour game, calculations show that its possible to get below 100 ton from LKO.

[magnemoe]

Lesson learned: I got pretty good delta-V data for the transfers.

The reuseable lander is to large, 4000 m/s is overkill, 3200 m/s is enough for Duna and Val, also enough for low Eve orbit to Gilly then Gilly is moving slowly far from Eve.

Not enough for Mun, so I add and drop tank during design. The laythe resupply module worked very well, rather add an second stage or an disposable multi stage lander to it.

Looking into if I can make it with just one engine, with either side or top docking port.

Use an disposable two stage lander for Moho, lighter and not much cost effective to drag back.

The first stage is to after Duna where it just take the Laythe resuply probe, the Tylo lander and fuel for refueling at Tylo.

Small stuff, adding ladders up and down from the command module, more important seats for the Tylo and Eve lander, using ladders is an pain.

[BostLabs]

Come on guys, comment!

i just found this. I'm here and this is AWESOME!

[magnemoe]

i just found this. I'm here and this is AWESOME!

Thanks, I can give you the craft file if you want. Or wait for the next version who is undergoing part qualifications now.

New reusable lander on Duna.

Found that an 2700 m/s lander has enough margins for both Duna and Vall. the life belt tank is nice for adjusting fuel for low gravity moons.

Forward docking port makes docking easier, one engine to save weight.