The Liv Tylo - a Jool 5 odyssey

[AeroGav]

^{Werner :} 

"What do you mean, 'Inventory Problem' !"

^Gus:

"One of our warehouse staff caught a bag of Nachos with his bar code scanner by mistake.  Turns out they use the exact same SKU codes as the Rockomax Conglomerate.   Threw our stock control all out of whack."

Werner rolled his eyes. 

"So what do we actually have?" 

"Well doctor, we've just finished the manual audit.  Four NERVs, two Rapiers, Two Whiplash,  a Panther, and a Poodle, also", said Gus, rustling through some papers, " we found a some  Twitch motors in the creche facility.  They were being built into some kind of toy, but they still look serviceable".

Mortimer pulled out his credit card,  "What's the Rockomax sales number again? 321-800-800-?"

^{Gene :}
"No time for that Mort, launch window in three days"

^{Werner :}
"Well, that's it then.  We'll just have to make do with what we've got.  Tell your boys to keep everything small and light, if we follow good maths it should be possible"

^{Gene :}
"We'll need a spaceplane for Laythe"

^Werner :
"That too,  just for goodness sake keep it light.  The smallest wing you can get away with to reduce drag.  Simple and quick to build".

"At least they'll have plenty of Nachos" added Gus.

The following morning, Gene stepped into the hangar with Werner.    It took his eyes several seconds to focus on the towering leviathan in front of them.   

He read the stats off the sheet,  "255 parts, 187 Tons.."

Werner stood, ashen-faced.   It seemed like an age before he spoke.  A pen fell from his hand in slow motion, bounced once, then clipped through the floor and disappeared in a puff of smoke.      He knew that near the singularity of a black hole, time itself was slowed by the intense gravity, but this is the first aircraft he'd seen to have that effect on its surroundings.

"You'd better give the launch to Val", drawled Werner, his voice sounding like he'd just inhaled a balloon of sulphur hexafluoride, "She's been spending some time in the Kessna, and just got her PPL".

"Private Pilots Licence?", replied Gene.  "What about instrument rating,  multi engine?"

"Won't need it, clear skies forecast.  And we're not planning on having any engine failures.  Separations, maybe, but those are much easier."

"I'll tell 'em to pack", said Gene.
 

[AeroGav]

Gus put his hand on Gene's shoulder.  "Give her any advice you can.  You were the best damn pilot we had, till that accident".

 

The video feed came through from the cockpit. Val  yanked the sidestick back against the stop, and lunged for the ignition switches
"Ah Val, we might have to try a modification of the ICAO approved takeoff technique , with that drop tank in place.  Wait for 70 m/s in case we get a tail strike"

Werner , whose allotment was situated at the far end of the Runway, began to look worried.

"Vee one, Rotate!" called Bill

"Positive rate, gear up".   At an altitude of 3m, Jeb has already donned his helmet, though they were still six years from the Jool system.

"Ah Val", said Gene, "Ease off on the stick a little, let her get some speed now.  It hasn't got the best thrust-weight. Just try to stay out of the water".
 

[AeroGav]

The Tylo staggered through the air.  The slower she got, the less power the Rapiers made and the more nose up it flew, increasing drag.   If Val wasn't careful, they'd mush back down into the water.   Applying just enough back-pressure to stay above the wave tops,  speed crept upwards, first imperceptibly, then more quickly.  Finally at 150 m/s, it would hold level with no back stick and began to climb.   
Already by 3km the air was thinning noticeably, and Val began adding nose up trim to stop transonic drag killing their meagre climb rate.  

By 7km however, the drag from the high nose angle was threatening to do that all on its own.  So, at 260 m/s Val  set the trim back to neutral, and threw the switches for all 4 nukes - every little helped in this situation.

No longer making quite as much lift as it's weight, the Tylo arced over into a shallow dive.   

^{Boom and Zoom !}

"OK Val that's enough", said Gene as they passed 440m/s at 4600m.   Val cancelled the Prograde Hold on the autopilot and shut down the nukes. Starting upward again at 3800m, the Tylo streamed contrails from it's body.  Engine thrust had doubled,  but so, for the time being, had drag.

"Watch your climb, Val" , said Gene.  The nose had risen to a 20 degree angle by the time they passed 6km.  They were slowing down again, and in danger of falling back into the transonic region.  Val selected Prograde hold, and the nose began to fall.

Acceleration increased noticeably past 8km, and the Tylo began to arc over, peaking at 12km, levelling off again at 10,000m at mach 2.5.  Their lone Panther engine was shortly to become a passenger, but the other engines were now more than into their stride and able to take up the slack.

"Tank Separation", called Bill.   To everyone's surprise, the empty tank pitched up as it fell behind and shot upwards,  but there were no explosions, much to the disappointment of Jeb.
 

Edited January 17, 2017 by AeroGav

[AeroGav]

Climbing at 10 degrees and mach 3, the Tylo rapidly  shot to 20km , though without gaining much speed.    Bill looked at the fuel gauges doubtfully.   The  nacelles of the Whiplash engines were set to drain next,  yet fuel consumption had dropped significantly compared to lower altitudes.

"Be a real shame to have to leave any behind Val"

"I'm sure the engineers new what they were doing", she replied.
 

Arcing over at mach 3.5 and 20km, the next dip in their roller-coaster flight profile would take them under 14km and up to mach 4.3.

The thicker air burned some fuel, but not enough.  Despite being on Prograde hold, the denser atmosphere and high speed set them on a steep climb.  Val made a few token nose down inputs, to no real effect.

"It's getting away from me Gene", she said.

Gene didn't answer.  He'd never been past mach 2 in his life and this was entirely outside of his experience.  

Werner opened his mouth, pulled a slide rule from his pocket, then closed it again without saying anything.

There was still plenty of fuel in the Whiplash nacelles, yet Val was sorely tempted to stage, and take advantage of their steep climb rate, rather than level off and try an eke a few more m/s at a higher altitude in level flight.    In any case, this underpowered ship had not been expected to exceed mach 4.3 air breathing, and beyond mach 3.7 even the Rapiers lost thrust with every knot of increasing speed.

After a brief hesitation, Val  threw all four NERV switches. "You're right Bill, we can't take it with us"

"Mach 4.7" Announced Val, triumphantly.   Back at mission control however, Gene's brow was furrowed.

"They're descending again", he said quietly to Werner.  Was the craft actually gaining any more energy or just trading height for speed, and wasting fuel?

Seconds passed.  "Mach 5, 19km" said Bill impatiently.  He cast is eyes over the instruments.  Although the Whiplash nacelles were now empty,  the engines had yet to flame out, which was the agreed upon trigger for separating them.   Yet there was no imminent sign of them passing flameout height.

"15kN thrust? They're holding us back, Val !"

Val needed no further encouragement, a green hand immediately stabbing the release button. Everyone aboard was mesmerised by their looping arc as the separatrons fired.

The Tylo began to climb again, and skin temperatures fell back into the green, but remained at mach 5.   By 23km, the RAPIERs were producing just 50kn each, both speed and climb rate were falling.   "Switch!" yelled Bill,  and was immediately rewarded with a kick in the back as the engines changed to closed cycle mode.

They  accelerated to Mach 5.3, yet still began to descend again at 30km.  Val reached for the sidestick.

"No ! We're on the expensive juice !", said Bill. "Stay on Prograde to minimise body drag.  I'm sure we'll level out before we blow up".

Bill was right, but it was an uncomfortable moment.  At 25km, a combination of lift from the wings, with their 3 degrees of built in incidence, and orbital freefall effect (due to being at 85% of orbital velocity) finally arrested their descent.   Yet temperatures continued to climb for another 15 seconds, peaking at 85% of the nose cone's tolerance.

The push in their back abruptly lessened.

"Out of oxidizer !" Called Bill, as their TWR fell from 0.5 to 1 to just 0.2 or so. For a few moments, velocity stagnated as drag, at 26km, equalled thrust.  But they were climbing at 95m/s and their wings were still making lift equal to  half their weight.

20 seconds, and 2500m later, drag had halved yet climb rate was  now 150 m/s and AP heading over 38km.

70 seconds later, at 40km, Val called "MECO!".  It was finally time to experience weightlessness.

Back at mission control,  Werner studied the telemetry and began fiddling with his slide rule.

"This is Werner", he announced, "I am pleased to report you still have 3391 delta V.  You can proceed to the Jool system."

Safely in space, the cargo bays were opened to help dissipate the heat of the launch process.  Meanwhile,  Jeb settles into the recreation lounge and starts killing time

Val gets clean :

Edited January 17, 2017 by AeroGav

[AeroGav]

As I've verified the craft at least reaches orbit without killing all its crew,  I have shared the file here

https://kerbalx.com/AeroGav/Liv-Tylo

There is also a version without the Kerbal Furniture mod, here

https://kerbalx.com/AeroGav/Steven-Tylo

Unfortunately the lack of recreation drove the crew insane, they resorted to eating brains, cannibalism, and opening gateways to another dimension to pass the time.

[Mister Dilsby]

Well that's some ship--'symmetry, shmimmetry' I always say!

I presume that the bathtub isn't actually filled with water, the ship being in orbit and all. Maybe that's why Val is wearing her EVA suit: I'm guessing the water is actually in the suit, with enough air pressure in the helmet to force it down so she can breathe...the tub is just there to remind the kerbonaut of comfy baths back home.  

[AeroGav]

6 hours ago, Kuzzter said:

Well that's some ship--'symmetry, shmimmetry' I always say!

I presume that the bathtub isn't actually filled with water, the ship being in orbit and all. Maybe that's why Val is wearing her EVA suit: I'm guessing the water is actually in the suit, with enough air pressure in the helmet to force it down so she can breathe...the tub is just there to remind the kerbonaut of comfy baths back home.  

It still has 2 way symmetry.  Whiplash top left and bottom right, rapier top right and bottom left, or was it the other way round?

The cargo bay must actually be pressurised.  It's just

• Val's got some really strange ideas about hygiene or
• the bay is pressurised but not man-rated, the Kerbals have to stay suited in case of explosive decompression 

More to the point,  Jeb's going to be very disappointed when he picks up a slice of that pizza.

I'll play this some more on monday,  atm i am in the jool system with 1100dv and can't figure out all the gravity assists.  I either get shot out past Eeloo  or   end up on  a terminal plunge into the depths of Jool,  to be crushed by the intense pressure.

[AeroGav]

Val stared blankly at the conic patcher.  Around a central green orb,  five multicoloured dots spun, orbiting at diferent speeds.

"This thing's making me dizzy!", she complained.

She reached up to the touchscreen to move the  node forward a few days, but her sleeve caught the Normal lever and added a huge polar burn, irretrievably corrupting the maneuver she'd been planning for the last two hours.

"Aggh! Who the hell designed this thing !"

"Get some rest Val, orbital maneuvers are my speciality", offered Jeb

"Must be all those hours playing Earth Space Program", said Bob

Val snorted.  "That thing's impossible"

"Completed it," Jeb said proudly,  " AND landed on the moon"

"No !", said Val, in disbelief

"It's true.  You've seen the video, haven't you Bob?"

Bob coughed.  "Well yes, but didn't you use the F12 menu?"

"No!" protested Jeb

"Well,  I could swear the video hitched as you were coming in for landing, and after that the fuel gauge seemed to stop moving"

"Just a bit of lag"

"Whatever boys," said Val, leaving her seat,  "I'll see you in a few hours".

Jeb took her place on the console and immediately set to work, tongue sticking out with concentration.   Their transfer orbit overshot Jools' slightly, reaching an AP of 77 million km and meeting Jool on the way back down.  It then swung around the back of the gas giant and would pass just in front of the large moon Tylo, whose gravity would slow them down.   The question was, what to do next.

At this distance, it was possible to have them pass very close in front of Tylo with only a tiny adjustment.  However this single pass would remove so much velocity they'd plunge into the depths of Jool after capture.   So, the first order of the day was to make this braking maneuver less aggressive so they'd get the bare minimum deceleration needed to stop them escaping the system.    At AP , another small adjustment would set their fate.

The first option was to allow a second encounter with Tylo to take place, and rely on a series of gravity assists.  The problem was the eccentricity of their orbit, too much braking would lower their PE to destruction in Jool's atmosphere, while their AP was still too high - he needed to get it below the orbit of Tylo to have a realistic chance of Laythe aerocapture.   So, Jeb tried to arrange decelerating assists from Laythe and Val , and accelerating ones from the tiny Pol, on the edge of the system, in an effort to circularise their orbit.     Unfortunately unwanted assists hampered this approach, and even when avoided,  years of maneuvers appeared to result in little progress.

So, Jeb decided to trust in the vehicle's thermal protection system,  and aerobrake in Jool's upper atmosphere.    At over 8km/sec,  they could dip no lower than 9km into its upper reaches, nevertheless the first three passes brought their orbital period down from a year to less than a month.

Just as the plasma receded from the windows at the end of the fourth pass, jeb caught sight of a faint cyan object, far to the right. 

"What's that Bob?"

"Laythe."

Jeb rushed back to the conic patcher.   Unexpectedly, they were on course to encounter the inner moon.   They would pass behind the planet and get a gravity assist that would pitch them out of the Jool system completely.

"No you don't!" said Jeb.

Burning Prograde was the easiest way to avoid the encounter, but would have undone all that hard won aerobraking.  So Jeb immediately began a hard retro burn that consumed all but 350 of their remaining delta V.   This would cause them to pass close in front of Laythe instead, removing so much orbital velocity that they'd crash into Jool if the aerocapture failed.

Jeb simulated a further retro burn, to pass a little further in front of the moon.  This would result in less gravity braking and would leave them with a PE just inside Jool's atmosphere and an AP just outside Laythe's orbit.   But the delta V cost was about 100 m/s beyond their means.

"This has to work", said Jeb, quietly.  

Fortunately, their retro burn near Jool PE had a disproportionate effect on their encounter velocity, perhaps because of the more oblique angle of approach and the fact that Laythe was catching up with them.    As they entered Laythe SOI,  orbital velocity fell by over 1000 m/s.

Unfortunately, as they fell towards the planet, it crept up again.

Jeb made a retro burn with half of their remaining fuel, which had the effect of lowering their Laythe PE still further, then he used almost all of the rest burning radial out to bring the PE back to 42km again.      Approaching from the dark side, Laythe loomed huge and ominous in front of them.  Jeb lowered the landing gear, opened all the cargo bays and pitched up for maximum lift.     The rest would be down to sheer luck.

Entering the atmosphere at nearly 3700 m/s was hazardous enough, but Laythe's air density increases much more rapidly than Kerbin's, going from space at 50km to thick enough for jet engine operation at 40km.   Temperature gagues quickly shot into the red, as did G loadings.

"Woah!" exclaimed Jeb, as the craft ignored SAS and began to tumble violently.   

"Clean up, we've captured" said Bob, struggling against the G forces.  

They'd lost a huge amount of velocity, and  their AP was now going to remain within Laythe's sphere of influence.  The only remaining question was whether they'd burn up, break  up, or auger in.

Jeb retracted the gear and one by one, managed to find the "close" switches for the cargo bays despite the violent throes of the aircraft.   As the last of the doors finally shut, the tumbling subsided.

 

"You'd better wake Val, I think we're landing", said Jeb.

[AeroGav]

Dazed, Val staggered into the cockpit.

"Jeb, what kind of re-entry was that?"

"Any re-entry where they can identify the remains is a good one", replied Jeb.

"Want me to get Bill?", he offered

"No, stay in the right seat.   There's no engine gauges for him to watch,  you can help me with the landing checklists."

"Jeb,  can you give me the glide ratios of this thing?  Should be something in the performance section", said Val as she buckled in.

Jeb pulled out the tray labelled "Performance charts", but it just contained a blank exercise book and set of coloured crayons.  

"Looks like they didn't get round to that Val,"

"Nevermind.  Trim four degrees nose up pitch"

"Set"

"What's our missed approach?"

"The Backstroke"

"That's a point," said Val, looking doubtfully out of the window. "Looks like we're headed into the ocean - Jeb , can you check the Kubble telescope images quickly and tell us where the nearest land is?"

"Uh, right behind us Val.     I'd really like us to put down on a big one so we've got somewhere to go in our Rover".

They'd re-entered on the day/night terminator and though the sun was just rising over the horizon, they were gliding into the half of Laythe that was entirely ocean.

Val wasted no time and immediately rolled into a 90 degree bank, pitching up hard to get on a reciprocal heading as quickly as possible.

"So we'll be landing in the dark then." added Bob

"What could possibly go wrong?" , asked Val, rhetorically.

Actually, the very first thing that could go wrong was running out of energy.   The turn had cost them most of the speed they had entered with, they were now down to 25km at mach 1.7.      Less than 100 units of liquid fuel remained.      Val left the Rapiers in closed cycle mode, where they sat silent for lack of oxidizer, and shut down the NERVs.   The lone Panther turbofan was switched into dry mode, where , at 9000 ISP, it was by far their most economical powerplant.   It also produced barely half the thrust needed to maintain level flight, and they slowly drifted downwards.       

At 5000m, it too sputtered and fell silent.   Jeb checked the Kubble images and compared with his radar altimiter.    

"We should be over the island now Val, it runs southeast, maybe turn 135 or something".   

The cockpit windows remained rectangular slabs of perfect pitch blackness.    

"Let me know if anyone sees the ground.  Don't be shy guys", added Val, trying to sound calm

"Damn" said Bob, straining his neck, "why are the windows so high up, it's like they designed this thing for giants".

"There !" Yelled Jeb

"I see it !" said Val.    They were low, she could already see the boulders.  No, they were stones.   Actually, gravel.

"So where the hell did we just land?" said Jeb.     
Beyond the reach of the landing lights, there was no other source of illumination. 
"Let's get some rest and wait for dawn".
 

[AeroGav]

Rather than post screenies I made a video of the misadventures on Laythe.   It's not particularly informative or entertaining but does serve as a record of what happened.

The rover was tested on Kerbin with 1 driver, but when fully loaded this appears to raise it's CG, as it was more prone to flipping, and unable to right itself unless the passengers dismount.   The plan had been to view the crater lake on the south of this island, but after 3 crashes (one of which destroyed the docking port, and the last of which killed Jeb - revert!) before getting even 20% of the way there, I abandoned the idea.

Finally, the re-dock feature, which worked really well on Kerbin's runway (lower the landing legs of the rover to raise it up, raise the airplane's legs to lower it down, and they meet in the middle)  does not work on hilly terrain.   A bit of cheating and the magic of video editing allows us to see what this might have looked like had it gone to plan.  I want to try the rover on Vall too, that's my justification, though  if this performance is anything to go by, don't expect miracles.   At least we can abandon it there - no plans to take it beyond.

Edited January 25, 2017 by AeroGav

[AeroGav]

The Rover party returned, six sets of gritted teeth, furrowed brows and bulging eyes greeted Bill.

"Folks, why the long faces?"

"That thing's a death trap!" , exclaimed Val

"What thing?"

"The Rover!"

"The Bathroom!"

said Val and Tanra, simultaneously.   

Everyone turned to face Tanra.  

"The Toilet, it tries to catapult you through the ceiling", she offered by way of explanation 

"..surely I'm not the only one to notice...  we've been on this ship for five years"

Bill shrugged.     

Jeb looked glum.   He'd personally supervised the development of the ground vehicle, which he named after his first car, the Voxel Nova.     Like the Nova, he was refused permission to fit a body kit , this time for part count constraints rather than insurance premiums, but he'd still hoped to impress everyone with his driving skills.

"Well, I've had a relaxing few days anyway. Catching up on Jackie Chan movies, prospecting for ore, eating pizza."

"How long till the tanks are full ?" enquired Bob

"Well, we're not taking any oxidizer, so it'll be done pretty quick.  Less than two years.  Just got time to get some snacks"

Engines running, drill retracted, cargo doors shut, the Liv Tylo sat ready to depart.

"Kind of wishing we didn't dump those Whiplashes back on Kerbin", said Val

"Well, there'd have been the delta V cost to bring them all the way out here...  how much fuel did we land with again?", replied Bob

Val pushed the throttles up, and released the brakes.   For a while , the craft was motionless, then slowly, it began to move.

"5 m/s"

"10 m/s"

"15 m/s", called out Jeb from the right seat

"Is this thing set right?" asked Val, pointing to the navball,  "It's showing retrograde"

"Unfortunately yes", replied Bob, " we're sliding backwards down the hill",

"What!?" exclaimed Val, "It's not even that steep!"

Val reached down for the nose wheel tiller, then realised there wasn't one.

"How are we supposed to steer?"

"Can't make landing gear this size steerable, we all know that", said Bob, "besides, why would you need to steer when you've got a whole planet for a runway?"

Improvising, Val pulled one of the throttles to idle, and the craft slewed round to face sideways across the slope. Finally , it started to roll forwards, heaving and lumbering across the uneven ground.    It began to catch air as it crested the hillocks.   Val noticed that pulling back on the stick softened their landing, but also bled velocity.  Better to let the wheels support their weight than have the wings  do so at the expense of drag.  At the same time, there was only so much abuse the structure could take.      Finally the ground fell away beneath them and they were forced to start flying.  Val turned due east and allowed the aircraft to sink almost to sea level, before beginning the long climb to orbit.

[Gordon Fecyk]

On ‎1‎/‎18‎/‎2017 at 1:53 AM, AeroGav said:

[About the predecessor vessel Steven-Tylo] Unfortunately the lack of recreation drove the crew insane, they resorted to eating brains, cannibalism, and opening gateways to another dimension to pass the time.

Is this the Steven-Tylo or the Iktomi? Sounds like that crew forgot to pack extra dice.

/me ducks

 

Edited January 27, 2017 by Gordon Fecyk
grammar

[AeroGav]

3 hours ago, Gordon Fecyk said:

Is this the Steven-Tylo or the Iktomi? Sounds like that crew forgot to pack extra dice.

/me ducks

 

I was referring to the film  Event Horizon . Sadly, no-one has recreated this yet on KerbalX.   It'd be nice if they can get most of the features right, but don't worry too much about the details because where we're going, you won't need eyes to see.

[AeroGav]

"3700 dV!", Jeb mocked, checking the fuel gauge,  "to get from Laythe orbit to the surface of Vall,  what sort of maneuvering is that!"

"So what," Val retorted, "we can refuel on the surface.  Besides, maybe if you could have torn yourself away from Dolph Lundgren films and given me a hand in here it would have gone better"

Suddenly Bob leapt out of his seat,  "

"

"What do you mean?" , exclaimed Bill

"What happened to your face?" , exclaimed Val

"What happened to your orange suit?" said Jeb

"The gravity of this place is much higher than we thought.  We might not be able to take off again."

"But it looks just like Minmus!", protested Val

"It's actually worse than the Mun," said Bob

"Don't worry,  I know how we can take off," said Jeb, "Bill, stop mining when we're half full and don't make any oxidizer or monoprop."

Bob pulled out a slide rule,  "That still only gives a TWR of 1.15 to one and our engines are oriented horizontally..."

"Relax, I'm a pro.    I'm going to see how the Rover performs on Vall while we fill up"

 

Some time later, Jeb returned.  His suit was stained with regolith and soot, and the plexiglass of his helmet crazed from several impacts.

"How'd it go", enquired Bill

Jeb didn't answer.

"Well, at least that makes us a bit lighter.  Every pound will count," said Bob

 

Edited January 31, 2017 by AeroGav

[AeroGav]

"Woah", exclaimed Jeb, "Where did that big mountain come from?"

"At least we missed it," said Bill

"Yes, but to do that i couldn't fly due west.   We're now in a bit of an inclined orbit.  It was either that or climb straight up more, defeats the point of getting that ski jump off that hill with miles of flat terrain in front of it".

"Should we have driven to the big mountain and flown off that instead?", enquired Val

"Long drive that," said Jeb, "..and I think I'm done with driving", dusting himself down.

From his seat at the Nav station,  Bob  plotted a few maneuvers, and frowned. "I still don't think we got enough.  Look, 850m/s burn to escape to Pol, when you correct for inclination.    And the capture burn's almost as big. We've only got 1600"

Jeb moved to the console. "If we get an assist of Tylo, we can have our AP  out to Pol for less than 300"

"And a tiny prograde burn at periapsis on Tylo will kick us out even more,  because of Oberth"

Jeb made some more adjustments, "If we wait till we're at our AP, our velocity is lower and we can correct inclination much more cheaply"

Jeb experimented a little further, "ok, if I make a tiny retro burn on our 3rd orbit, we get an intercept next time around".
 

[AeroGav]

 

[AeroGav]

The hop from Pol to Bop was probably the least demanding of the entire mission and it was decided to not waste time fully loading the tanks -  a slightly under 50% load of LF with no OX or mono would give 3000ISP, likely to exceed requirements by a very large margin.

Here is the takeoff -

dv  used by liftoff - 121 m/s

circularisation, escape - 63 m/s

It took 208 m/s to match inclination -

139 m/s retro burn at PE then gave us an intercept with us passing close in front of BOP (not too close, i found out it has much higher ground than you'd expect for it's size!), which gave us a gravity assist brake - i reasoned that might make the capture burn smaller.

Finally, here is the landing.  The capture ,deorbit and landing burns consumed 443m/s.   We'd brought 3 times as much delta V as needed for this leg of the trip.

 

[AeroGav]

 

This was to be the  final fuel stop, before the punishing visit to Tylo and return to Kerbin, as such i took advantage of the fairly low gravity and filled ev-ery-th-ing,  LF, OX, Mono and ORE.

Despite having two of the largest reaction wheels in addition to the torque of the mk2 lander can, cupola and mk3 cockpits, the ship is barely controllable fully loaded like this. 

Only when editing this video for upload did i see that our "oops" moment in fact caused some damage,  tearing off the left rudder.   Hopefully it's flyable without, because by the time i'd watched this back i'd already flown the tylo landing.   And I do not want to do that again, ever !

On Pol, half filling the LF brought over 3000 dV, but loading to the gunwales here extends that to just 4447.  Diminishing returns, but also, that oxidizer, monoprop and ore is not contributing to LV-N propulsion and is merely being counted as deadweight.

According to the Kerbal engineer, only 172 was lost taking off and establishing orbit, though that figure has no doubt been lowered by the IRSU converting our ore back into LF.

Bop escape cost - 208 m/s.  It left us with the following trajectory - 

Our PE wasn't far off an encounter already, but that inclination had to be eliminated, and it was costly - almost 600 dv.   More than four times what we paid to create that inclined orbit on the way out, probably because our velocity is higher, but I'm almost certain this could have been done better.  Maybe if i'd took off from Bop on some heading other than 90 degrees?

Oofya - after paying the ferryman his pound of flesh, the retro burn to work an encounter was a pleasant surprise.  I made a slightly larger burn than necessary to pass close in front of Tylo and get a strong braking effect.  I reasoned that'd be a good thing, given that we're working our way inwards.

However, whilst it didn't take much to complete capture around Tylo, the burn to pull our PE down went on and on. 

Cost to go from intercept to low orbit - 1443dV.

This was troubling, and I was starting to have doubts of getting back to Kerbin.     What could I have done to give me more breathing room?  I could have gone back to Pol  to top off before heading down to Tylo,  but I wanted to avoid backtracking in this mission.  I also wanted to avoid more than the bare minimum of docking,  and in any case the fact our ISRU is on the lander ruled out leaving the lander in orbit and sending the plane back to an outer moon to refuel.  

I could have decoupled the propulsion module of the lander, since the resource converter is attached to the accommodation section,  but i don't know how much extra margin I'd get for all that work.

 

 

 

[AeroGav]

"Bring me in as low as you can Val,", Jeb radioed from his Cupola to the cockpit.   

He tried not to show it, but he was feeling under pressure.   The margins of this lander were razor thin , and  five other lives depended on him.    Running short of delta V in a spacelane meant a dead stick landing and a long walk of shame back to the base.   In an atmospheric rocket launch, you'd pop the chutes.   But on an airless moon, once you started the engine, you crossed the rubicon.  Land , or crash.  Make orbit, or a huge crater.   After takeoff, the impact velocity would get more severe with every passing second, unless safe orbit was made. 
 

 

[AeroGav]

The lander discards the empty propulsion module and docks with the Liv Tylo.

I needed help from the forums to plot a good route back to Kerbin,  having less than 1300dV remaining.  I was in two minds whether to refly the mission from Bop,  depositing the fuelled lander propulsion stage in orbit around Tylo at 30km then heading back to Pol to brim the tanks.  

Alternatively, we could have dumped the lander altogether and shaved 6 tons off our dry mass, which would add quite a bit of delta v to the airplane.  It actually has more than enough seats for 7 kerbals, thanks to the kerbal furniture parts -

• bathtub has two "seats"
• toilet - one seat
• sofa seats two
• cockpit has four seats
• souls on board - 7 

But with an efficient ejection burn where the ejection from Tylo is in line with your ejection from Jool and both are retrograde with respect to Jool's orbit around Kerbol, it's possible to lower your PE to Kerbin's height within this budget.

Always a relatively spacious ship,  the Kerbals practically rattle around now that cavernous cargo bay is mostly empty 

...which was just as well because we were unable to aerocapture on our first pass, and ended up shooting off into orbit around Kerbol again, despite dipping low enough to even up our asymmetric control problem by melting off the other rudder.  Well, GoSlash27 reckons they're a bad idea anyway.  So we spend an extra 50 years in space, glad i gave these guys a TV.

Eventually, a second encounter occurs - still no capture, though this brings our PE below Eve!  

Finally, on the third encounter, we manage to aerocapture Kerbin.  By this point, i was using the lander's RCS to make single digit delta V course corrections.

 

Edited February 3, 2017 by AeroGav

[AeroGav]

The final matter of re-entry and landing.   The mk3 cockpit was surprisingly  prone to overheating, far more so than on some of my inline mk1 designs, and especially given how well it stood up to the aerobraking.  Perhaps, being at the front of a very large ship, it is getting more than its fair share of prolonged heat soak.  Also, the fact we're orbiting the wrong way around Kerbin probably isn't helping matters.

Whilst i'm no good at plotting orbital maneuvers, I'm in my comfort zone with stuff inside an atmosphere.  By adjusting pitch closer or further from best glide AoA, i am able to adjust our aim point.   There is the final matter of landing in the dark, but even that wasn't much of a challenge.    I put down on the space centre first time, but decided that since this ship is now probably highly radioactive, it's probably better to put down in a disused airbase.   We had a bit too much height due to me not being able to see the runway till rather late, so it took a couple of attempts to make the right kind of height shedding maneuver for a reasonably neat landing somewhere within the airport perimeter.

Lessons learned?

Well, I'll probably update this thread a bit more over the coming weeks, I just wanted the damn thing finished.   But a few things really stand out

• My itinerary was wrong.        It made sense to visit Laythe first, so we could shed the airbreathers.    Tylo has to be last, since we can't refuel on Tylo and loose the ability to ISRU after going there.   We should have gone to Pol before Tylo, since unlike Vall, we can carry a full load out of the place, and unlike Bop, we won't waste a ton of fuel correcting the plane change.        And since we are gross weight limited coming out of Vall, Pol is about the only place we can go after Vall.   So, the second destination, after Laythe, should have been Bop.    

TL;DR -   should have gone Laythe, Bop, Vall, Pol, Tylo

instead of Laythe, Val, Pol,  Bop, Tylo

• Don't bother with a Rover.     Such a waste of payload.   The airplane itself could taxy over the ground in a more stable way than the rover ever could.

 

• Bring a radiator and more Reaction wheels - Two large reaction wheels not enough when a ship this size is fully loaded.   Refuelling took years - seconds from my point of view, but we could have greatly increased mining speed at minimal cost by bringing a small deployable radiator.  The drill was overheating and so ran at only 7% load the whole mission.