Grand tour 4, new attempt at an below 100 ton grand tour

[magnemoe]

After the tragic death of Neildan Kerman during the fatal Eve accent, we went back to the drawing board. It was obvious that the lander concept with ladders was deeply flawed, as in it had an huge chance of fail during the last part of launch and circulation.

An new design where the kerbal would stand on the ladder was tested successfully both in suborbital tests on Kerbin and simulations of landings on Tylo and Moho, however Eve looked like was an hard nut to crack.

An design with a seat would work, however it was 15 ton who would break the 100 ton limit.

However after 30 test we found an design who usually worked and was ready for Grand Tour 4.

First we had to select an pilot, this was combined with testing an new huge solid state booster.

The booster test failed as it separated from the pod during start of gravity turn, but the pilot selection was easy. Hanfred is remarkable because his high courage while his stupidity level is low, he admired he accepted the mission to get away from his wife.

The rocket, 665.6 ton, 729 parts on pad.

Activating, the two side nuclear engines to help increase TWR a bit, found an staging bug, the center engine and one of the side ones started so I had to rearrange stuff, luckily the center stage did not blow up.

Ship in 125 km orbit before any missions is, 99.17 ton with 529 parts.

Ship in 125 km orbit before any missions is, 99.17 ton with 529 parts.

New Eve lander, 1.5 ton heavier than the old, 90 liter more fuel on the Eve transfer drop tanks.

I changed all the landers, also switched to junior docking ports for stage two, the reuseable lander and the docking tanks, still use standard docking port for the center stack up to Eve lander.

This was done to use an side docking port on the reusable lander, this required changes to all other docking ports second stage would use.

Lander underway to Mun with an good view of the docking port, the Mun landing reqired an first stage, 45 liter fuel is a bit overkill but reducing it would increase part count while only saving some kilo.

On Mun.

As suspected the Mun lander on the monument is an hoax.

After return ship is refuled by the LKO service probe, while Hanfred is back in command module to fill helmet with snacks.

The LKO service probe was an disappointment, had been better to dock with mothership.

Minmus is more fun.

Now for the serious part, the Eve mission.

Edited September 1, 2013 by magnemoe

[Kerbal01]

What booster is that? The ariane 5 EPC?

[magnemoe]

Eve or burst, her the first two drop tanks are jettisoned together with 60 liter spare monoprop for LKO operations.

Eve trip from 125 km LKO to 105 km Eve orbit cost 1520 m/s dV,

Started from LKO with 6166 liter fuel and 504 parts, arived eve with 4580 liter fuel, 3.5 below budget, I used 3.5 liter more than the 1620 liter in the forward 720 liter tank and the drop tanks.

This and that Gilly's position allowed me for an intercept at its Ap so I decided to let Hanfred use the main lander instead of the Moho ion stage and extreme eva for Gilly.

Main issue with Gilly was that the lander glide downhill for over an minute after landing, this was however more annoying than dangerous.

Hanfred jumped a bit higher of joy than usual.

Now for the serious stuff.

Eve lander and the Eve transfer stage is separated.

8 48-S7 engines in asparagus, an deorbit tank on top, with 45 liter fuel for each side. This was hard to figure out, could not use an single tank on top as it would create an fuel loop.

Two of the engines is place higher than the other for balance during the first part of accent. This was an even larger nightmare to figure out, tests on Kerbin worked well but lander rolled in Eve thick atmosphere so it needed the higher placed engines, however at around 14 km attitude the two engines has to be disabled shortly before burning out as I else would get trust above center of mass.

Yes this is that I have been doing since grand tour 3.

Hanfred does not like the transfer from seat to ladder while on an suborbital trajectory, seat is then jettisoned after this, strangely enough the ladder is an more robust place during parachute opening who tend to make kerbals fall off seats.

An proud moment:

Celebrated by firework, by jettisoning the legs.

Launch profile settings

On the way up.

Lander is a bit troublesome, in addition to disabling the high placed engines I had to switch to manual control once the last stage with the ant and oscar was activated as the autopilot would wait to long starting it so I would reenter the atmosphere 3 km below Ap, might be an idea to go for 105-110 km, however I still run out of fuel and has to do the last 60 m/s by the eva jetpac. Not an big issue as I would had Hanfred leave the ladder and pick him up with main lander anyway as you can not time warp on ladders, this was also the reason for the seat during decent, I had to wait around 6 hours for sunrise and my orbital plane to intercept the landing area.

[magnemoe]

What booster is that? The ariane 5 EPC?

Its an Novapunch 77 ton, 3200 kN booster, yes its insane powerful, more than twice the power of an mainsail, with only an pod it has around 5000 m/s dV but is not able to reach orbit because of air resistance.

Project is only stock parts with the exception of mechjeb.

However the seach for an badass pilot is not really an part of the grand tour trip so I wanted to have some fun, became more fun then the separator broke

The pod reached 200 km attitude and landed back close to the spaceport.

[magnemoe]

Moho rider, the ion powered transfer stage to Moho was the only thing who was not detail tested before launch, this is probably why it worked better than expected.

TWR on 0.12 is far better than expected, as much as the mothership at start of Eve mission.

In front is the 0.5 ton Moho lander, uses an ladder and is designed to land from an 12-15 km Moho orbit. Hanfred will exit it in orbit and be picked up by the transfer stage.

The decopler to seperate the center part to use as an upper stage look like overenginering with over 10 km/s dV.

My first ion powered craft outside of small probes.

[magnemoe]

Finishing Moho.

Solar powered craft has one serious downside:

Moho landing, landed from an 12 km orbit, Moho is far more rugged than before, wonder if it deflates from the moholes? Anyway the crater bottoms are flat.

And takeoff:

Look like I have an comfortable 12 m/s safety margin.

However I ended 160 m/s short, so I had to finish in eva while the mountains came and tried to come out and touch me.

Result was that I overdid the circulation a bit.

Anyway, found I had enough xenon left to take me to Duna with decent margin, could probably reached Jool if I dropped the side engines then out of fuel.

However I will return to Eve and continue to Duna with mothership.

[The Destroyer]

Oooh I like this I can't wait for more!

[magnemoe]

One observation, both the Eve and Moho lander with ladders did run out of fuel short, for the Eve lander I assumed this was because of inaccurate manual burn with the and and oscar, I landed higher and had more fuel left in deorbit tank than the last test.

Moho was done entire with mechjeb and here the unmanned left me with 150 m/s short instead of 300 m/s spare.

I wonder if the kerbal weight is used if he stand on the probe core during burn.

[tavert]

I wonder if the kerbal weight is used if he stand on the probe core during burn.

When the ladders are parallel to the thrust axis, yes. That counts as a collision and the Kerbal does exert reaction forces, requiring more fuel to accelerate. You only get the Kerbal mass for free when the ladder is perpendicular to the thrust axis.

[magnemoe]

When the ladders are parallel to the thrust axis, yes. That counts as a collision and the Kerbal does exert reaction forces, requiring more fuel to accelerate. You only get the Kerbal mass for free when the ladder is perpendicular to the thrust axis.

Makes sense, benefit is that nobody can say I used exploits

However I might have to change the Tylo landers landing and takeoff profile even if it was tested with kerbal.

My problem with the horizontal ladder was that the kerbal tend to slide to the sides and making the lander side heavy. This did not happen on my first grand tour but has been common on later tests. This tend not to be an problem during launch but become serious during circulate.

[magnemoe]

During tests of the Tylo lander to verify that it works with Kerbal on ladder and finding optimal flight profile I found that the existing lander works well with an decent margin.

I also noticed that the kerbal made the upper stage with ant and oscar had 25-30% less dV than shown.

I wanted to test if it was any diference if kerbal hang on ladder or was standing on probe core and run into an very amusing bug, the kerbal was stuck in climbing animation pushing against the struts blocking him from falling off.

This generates around 1.5g of reaction less trust, the Bill has climbed well past solar escape speed and is not stopping.

This

Result in this

Edited September 2, 2013 by magnemoe

[magnemoe]

On to Duna and run into an very weird bug, one of the three LV-N was using far to much fuel, almost as it was running in atmospheric pressure however I did not check the

At start of duna burn the ship was 61.8 ton with 4794 fuel, the Duna burn was 1659 m/s, after the burn ship was 40 ton with 2011 fuel left.

dV calculation gives ln(61.8/40)*800*9.81=3414 or more than twice of 1659, I dropped two drop tanks but dry mass is less than 0.5 ton.

Downside is that I have to go back to before the mission Moho as I did not store the save before this burn and managed to quicksave afterwards.

The lowest 1.25 meter stage in the image was the problem, the part who will visit all bodies and return, the center one will take the Laythe resuply module to Laythe and the Tylo lander and more fuel to Tylo. the top stage will be left at Duna

[magnemoe]

Because of the fuel use bug I had to do Moho again, booring even if the in-flight movie was interesting

http://forum.kerbalspaceprogram.com/showthread.php/41001-Is-it-at-all-possible-there-was-a-civilised-species-on-Earth-long-before-humans?p=634081&viewfull=1#post634081

Enough prehistory and into the future with 100.000x warp.

he Moho trip used far more xenon than last time, I had to return home in the small center stage

Main downside it look far cooler with the three engines, now it look like an scooter.

As it my calculations after the bug showed I would be a bit short of fuel I decided to stage more aggressively.

Dropping tanks.

And dropping engines.

Dark image but I actually drained the stack with only fuel and engine and dropped it during the burn.

Later dropped the two drop tanks for the upper stage.

Even if off center the ship handles well enough as I drained fuel from the side with no engine below and has two torque modules.

At Duna ship was divided, the upper stage kept an 90 liter docking tank and got the lander back. Lower stage undocked the 2.5 meter part on top and rotated it so the Laythe resupply module came below the service module so it would be easy to drop.

Duna transfer cost me 1620 m/s + 322 m/s plane adjust.

In Duna orbit before separation ship weighted 42 ton, 227 parts and 2562 fuel.

Lower stage stayed in an orbit with Pe 80 and Ap 1200 km while upper stage did another aerobrake to an 70 km orbit.

[magnemoe]

Finaly Duna landing, after all the work it was good.

On ladder back to command module

That ladder makes life a lot easier.

I don't take Ike as serious.

Trip to Ike was 279 m/s with 120 circulate.

After Ike I put the second stage back into pretty much the same orbit as first stage for Dress transfer.

First stage dropping the service module with the torque modules before Jool plane change.

Cost of Jool burn so far is 1034 m/s + 106 m/s plane change, will be some minor adjustments to get an Laythe intercept.

Second stage went to Dress.

770 m/s + 88 m/s adjust did not do plane change but was lucky as I could adjust my orbital plane for 17 m/s before finishing circulating for 787 m/s

Two years to the Jool transfer window.

However the good news is that the fuel situation has changed, the upper stage has more than 2000 m/s dV left. Upper stage will have to drop the Laythe resupply module with more fuel than the second stage can carry and will be full then going to Tylo so I will have more enough fuel to finish this mission.

[magnemoe]

At the same time Hanfred is enjoying Dress the first stage is entering Jool SOI and is set up for Laythe aerobraking.

Downside of hitting Laythe on that side of Jool is that you only have 8 minutes from entering SOI to Pe so you better have set up things before getting were.

To increase excitement, Tylo wanted to help so I had to do an 44 m/s fix in addition to the 70 m/s burn to set up Laythe intercept then entering Jool SOI.

And yes, notice that I'm almost out of power, naturally Jool would eclipse the sun so I run out of power, had to be quick to do the last corrections.

However main benefit is that it would be fast no matter how it went

Hard aerobraking

After entering an eccentric orbit around Laythe I dropped the Layte resupply module.

Her it do an second aerobrake to get into an holding orbit waiting for second stage.

First stage continued to Tylo where its waiting for second stage in an eccentric orbit.

It only cost 300 m/s to get where but to circulate at 100 km will cost 900 m/s.

[magnemoe]

Finaly the upper stage got it launch window and set off to Jool and Laythe.

605 m/s burn and 223 circulate and adjust. Funny enough the upper stage had to catch up with Laythe and had just 600 m/s aerobraking.

I used around 200 m/s on both the resupply module and second stage to adjust planes and meet so I just had around 80 liter fuel left in the resuply module then I dumped it.

However I would managed to visit Vall and then to low Tylo orbit with half tank.

Separating from resupply module

Landing on an tiny island I have thought I should visit before.

Tried to go to the beach but is multiple kilometers.

Look like I have the usual circulate problem and has to Eva.

Had tested the Laythe lander multiple times, however during the tests I did an manual shallow landing, here I used mechjeb autoland for accuracy and mechjeb do an far to long deorbit burn, think the tests might used 60 km orbit to.

[magnemoe]

Val was pretty routine. More expensive than it should be because an not optimal transfer, yes staring from 60 km Laythe orbit added to the cost. 750 m/s to get where including adjustments and 293 to circulate.

Tylo will hardly become routine, First stage used 800 m/s circulate at 100 km,

Upper stage used 525 m/s from Val to Tylo another bad manouvre however its hard to get transfers between Jool's moons optimal.

860 to circulate in multiple steps to meet with first stage.

Tylo lander seperation before docking upper and lower stage, did not need the docking port on top of lander who saved the previous tour.

Details of Tylo lander

The seat is for orbital opperations, kerbal will use the ladder to move to the ladder construction on upper stage for the actual landing after deorbit burn.

The two oscar tanks is to balance seat and kerbal, they will be drained and dropped after deorbit burn.

Drop tanks should last as long as posible, try to make your own landing more gentle than the one the drop tanks had.

I forgot to extend the upper ladder and fell off

Back in orbit with plenty of margin.

As the lower stage had over 720 liter fuel left and the upper 160 liter I found I should just transfer some fuel to upper stage and send the lower to Bop, this way I would get more than 5000 m/s dV for the Eeloo transfer and return and be more flexible with the Eeloo transfer.

[magnemoe]

Stage I used 754 m/s + 539 m/s plane change and 289 m/s to circulate at Bop

Stage 2 used 770 m/s + 13 m/s plane change and adjust + 296 to circulate at Pol.

Lander landed on an hillside and is gliding down to the bottom.

Gravity is pretty low.

To low for Mechjeb landing autopilot however you can use it to do accurate deorbits. Yes I remembered it this time, I also avoided ending up in retrograde orbit.

Going from Pol to Bop cost me 88 m/s, 169 m/s plane change and 153 m/s circulate. Look like my gut feeling was right then I always preferred to do Pol first.

[magnemoe]

During docking first and second stage at Bop I managed to accidental redock with the lander. I undocked it, moved the 1 stage a bit back to 2 stage who I moved forward and managed to hit the lander so close it docked again.

One benefit with the junior docking ports then docking small stuff is that the magnetic force is much weaker, the standard docking port might rip things like seats off an small lander who is low on fuel and only weight a bit over 100 kg.

Anyway after transferring fuel I had 448 fuel in 2 stage, 3910 m/s dV.

Got the weird texture bug again, it changes depending on distance so you can not land on the border.

I did not visit the Kraken, however I fond something even weirder on Bop.

First sign was an black mark.

Using jetpack to investigate.

My goods its full of stars

I think I recognize that planet.

Another long distance view of the crack.

[magnemoe]

Rounding this up.

I used around 700 m/s to get out of Bop orbit, then adjust the alignment and orbital plane so mecjeb could give me an node for Eeloo, I got an 400 m/s burn who would only take me closer to Jool in a bit over 4 years.

However it told me Eeloo would be close to Jool after two orbits, I had 448 liter fuel and 4743 m/s dV and could experiment a bit.

So I planned this burn.

498 m/s to get into solar orbit. 430 m/s to align planes and some adjustment, 14 m/s to correct one Jool year before intercept. Circulating was 790 m/s

Eeloo was undramatic.

Retun home was pretty standard but look at the flags.

1700 m/s burn 465 m/s adjust and plane change followed by 107 m/s circulate.

Was a bit surprised that the upper stage was unstable during aerobrake but I had only done low speed aerobrakes with it at Duna and Laythe.

Ended up in an orbit 45 degree of equator. Could have kept the Ap high and adjusted but did not bother, instead I filled up the lander with 45 of the 55 liter of fuel left,

Lander had 2581 m/s so I just told mechjeb to land at KSP.

it used 1400 m/s landing, probably the most expensive landing I have done outside Tylo.

[ChrisWill]

Wow, 11.7 years to complete this mission according to the MET in the second to last image. Impressive work really enjoyed this.

[SuperWeegee4000]

Just a friendly tip: "An" goes in front of words that start with vowels, such as "apoapsis," and "a" goes in front of words that start with consonants, such as "periapsis." Blame my OCD.

You certainly have the skills.

[magnemoe]

Wow, 11.7 years to complete this mission according to the MET in the second to last image. Impressive work really enjoyed this.

Most of the time waiting for Eeloo intercept, going where and back. Last time I had to wait 13 years, but this time I was a bit smarter with the transfer.

[UH60guy]

Can I ask how you went about planning the route and the delta v requirements? Did you have to build some huge excel spreadsheet or something to track it all before building?

[magnemoe]

Transfer costs as reference, all costs are low orbit to low orbit unless specified, many minor adjustment burns are not included but all major ones.

Kerbin -> Eve: 1514 m/s (1520 m/s on grand tour 2)

Eve -> Gilly, this can be done with a bit over 2000 m/s if you meet up with Gilly at is Ap and aerobrake on return.

Eve -> Moho: 6102 m/s (6020 m/s on grand tour 2)

Moho -> Eve: 2804 m/s :1500+132+ 1537 plane + 135 adjust , (2950 in grand tour2)

Eve->Duna: 1957 m/s : 1620 m/s + 322 m/s plane +15 m/s adjust. (2026 in grand tour2)

First stage:

Duna (80x1500 km orbit)->Jool SOI: 1140 m/s : 1034 m/s +106 m/s plane and adjust. (1152 in grand tour2)

Laythe intercept: 70 m/s, 40 m/s to correct for Tylo SOI.

Laythe (90x2000km orbit)->Tylo: to Tylo (100x6000 km orbit) 447 m/s

Tylo additional 900 m/s to circulate at 100 km.

Tylo->Bop: 1582 m/s: 754 m/s + 529 plane + 10 adjust + 289 circulate.

Stage 2:

Duna->Ike: 399 m/s

Duna (80x1500 km orbit)->Dress 1645 m/s, 770 m/s burn with plane adjust+ 66 +22 correction +787 m/s circulate. (2438 for grand tour2 who went to solar orbit first)

Dress ->Jool SOI: 828 m/s: 605 m/s + 223 m/s plane change and adjust.

No data for Laythe, probably to low, you need small adjustments at Jool SOI. (Grand tour 2 came in out of plane and was expensive)

Laythe->Val: 1031 m/s : 601 m/s +137 plane and adjust + 293 circulate. (923 m/s at grand tour2)

Val->Tylo SOI: 525 m/s, 862 m/s to circulate at 100 km.

Tylo->Pol : 1079 m/s : 770 m/s +13 adjust + 296 circulate. (1104 m/s at grand tour2)

Pol-> Bop: 410 m/s : 88 m/s+ 169 plane change and adjust + 153 circulate. (454 m/s at grand tour2)

Bop-> Jool orbit outside Bop pretty circular and close to plane around 600 m/s

Jool->Eeloo: 1720 m/s: 498 m/s Jool escape + 430 plane and adjust+ 16 m/s adjust + 790 m/s circulate (1426 m/s at grand tour 2 but used over 14 years not 6)

Eeloo-> kerbin: 2271 m/s: 1700 m/s + 464 plane + 107 circulate. (1564 m/s at grand tour2)

Both this trip and Grand tour 2 was done as new games so most intercepts are the nearest possible at least up to Dress, this is why they are so like each other.