A Self-Refueling Spaceship's Grand Tour

[Jesrad]

The preposterous contract:

OK so my first reaction was to laugh and aim the mouse at at the decline button. But then, I'm in this business for the money, and there was a LOT of it behind this mining gig.

Plus I had been wanting to try my hand at a self-refueling interplanetary-capable ship lately. In fact I had all the calculations done already. So the call of money and challenge were stronger...

I toyed with three different approaches, and finally launched the product of my musings: a 250-ton SSTO-though-not-on-Kerbin behemoth rocket ship equipped with 12 drills, a 2700 ore capacity, ISRU, all the science equipment available including a lab, and enough gigantors to power it all up at once in Kerbin space and hopefully in Duna space too.

She sports a single KR-L2, giving her a TWR between 0.8 and 1.13 depending on how light I try to fly her. Because she is meant to be self-fueling, I did not bother with RCS and straight up lined her with Verniers instead which make her quite nimble, to my surprise. Launch from Kerbin was done with the help of 300 tons of LF-boosters in onion setup, but I fouled up my imgur and deleted those pics

So with no further ado, here she is, dwarfing my LKO space station:

I had no scientist available right away, though, and I figured that, instead of getting one from the science station with an Ulysse SSTO, and launching her again in the grand tour spaceship, I'd simply stopover on the way and pick her up. For some reason (a small amount of offset-clipping is my best guess) I couldn't get KSP to accept clicks on the lander can as transfer destination, and had to EVA'd her across:

Once done, the massive thing headed for its first stop: Minmus. The idea is, she'll refuel there, and be halfway to everywhere else in the Kerbol system. Minmus is a bit higher in deltaV and cheaper to leave, making it a more efficient stop for fuel than the Mun. I like my missions cheap and efficient like that.

Still being efficiency-minded I landed her in the Highlands, on top of the tallest peak of Minmus, as that was one of the few biomes unexplored so far:

Might as well make good use of those science instruments.

Fast approach and suicide-burn are most efficient, and thusly:

Everything up and running for the last Kerbin-bound refill:

The ore concentration turned out a little over 2% only at this altitude, but I was patient enough to not bother relaunching and landing into one of the Flats. Though, not patient enoug hto wait for full ore tanks.

From there on, the crew argued between themselves about their next destination. Liniella, being the only scientist aboard and outnumbered by the two engineers, lost the contest. She wanted to head inwards to Kerbol, but the engineers insisted on paying a visit to their Duna-colonist friends. Also, the intercept was good for Duna, and only tentative for either Eve or Moho.

Although I did not initially launch with ore in the tanks (it's expensive), filling the 2700 tank extends the range of the ship from 4875 to 5200+ m/s:

Here I'm taking advantage of the wait to Duna injection to convert the half-load of ore leftover from the refueling, to make the launch from Minmus "free as in beer". Ore has a density of 10, LFO a density of 5, and the conversion ratio is 1:2 so it's all the same in the end, having ore in store is pretty much equivalent to having an extra tank - as long as you can convert it to fluel in time.

I christened her the Grand Tour Star, for obvious reasons of unimaginativeness.

...and off into the blackness between...

Next stop: Ike ! I got a Periapsis of 450 km and a 312 days transit. Good thing she packs *tons* of snacks. Also, the science lab has been filled and running since before the Minmus stopover, for extra science points.

Edited June 16, 2015 by Jesrad

[Red Iron Crown]

Looks pretty awesome! Moving this over to Mission Reports.

[Mister Dilsby]

As ambitious as it is awesome. Looking forward to seeing you park that monster on Duna!

[GehringGame]

What a weird and wonderful looking ship! Great job thinking outside the box with the design. Can't wait to see you get to more destinations.

[Jesrad]

For the curious, the VAB shot of the Star before launch:

It fit into the 530k advance fee for the contract, even ! I told you I'm cheap: I'm making a profit even before the mission begins

And a big spoiler: the other design I made, adapted for the outwards-system lack of solar power, and differently styled into an octopus-kind of thing. Lacks a science lab because I have no more scientists to spare, and a single small ore tank because I do not intend to complete contracts with this one:

[GehringGame]

Wow! I really like your alternate design as well. I'm really drawn to these designs for some reason. Very creative. I'll be following the progress on this one!

How did that monster fly on the way up to orbit?

[Jesrad]

I'm glad you like it !

The first stage went flawlessly, but the second stage being rather limited in TWR I improvised a transfer of fuel from the "tips" of the star to the LFBs and extended that part of the ascent. I cut thrust a lot somewhere around 10 km because she was threatening to flip over, extending the ascent some more, and it was a wobbly ride on the back of just the Mammoth until I dropped it too past the 30+ km mark. From then on the KR-L2 worked beautifully and steadily, and she circularized in a 80x80 LKO easily.

I'd already trained a lot at launching large spaceships with the Cislunar Tankers for my Minmus Mining / Kerbin-Minmus L2 Fuel Depot operation.

Edited June 16, 2015 by Jesrad

[Jesrad]

Dun'hike

The adventure keeps unfolding... We left the Star and her crew as they were slowly tumbling around Kerbol, towards the rusty spot known as Duna, and its angry-eye-in-the-sky moon Ike.

About a month before SOI change, Linielle boldly adjusted the trajectory to get an aerocapture on first pass: Periapsis 23km. Meanwhile, Arena and Jenming scienced away quietly in the back seats of the Lab, and when they finally were in range of Duna, this happened:

Woops, better empty that bucket.

You know all those mission drills the astronauts do over and over and over ad nauseam, until they can do the planned tasks in their sleep ? That's what Linielle had spent her last month doing. When the Star breached the 140km altitude limit, she hurried out the airlock and went through every instrument at an insane pace:

She completed all of her assignments in record time, getting back in the hab before the ship reached the upper limit of the atmosphere.

In unrelated news, the coffee storage alarms report a breach.

The ship, still massing 117 tons, dipped at hypersonic speed into the tenuous and dusty layer of gases, and then something unexpected happened:

Oscillations quickly receded and she stabilized in this 30-degree-down stance... Crew double-checked the fuel levels for imbalances, and found none. Oh well. Closest approach was at 22818m altitude, and as she exited the atmosphere it became clear that too little airbraking had happened. She was still on an escape trajectory:

A long burn was required, with an antiradial component, to bring her into a closer, proper orbit around Duna:

It was time to prepare for landing...

- - - Updated - - -

One more short burn brought Periapsis to 15km altitude on the sunny side of Duna:

The aerodynamic stance of the ship proved unstable once more, but the Verniers quickly tamed it. Overpassing a deep canyon, Jenming spotted a suitable landing site, and Linielle fired the main engine to bring the Star to a standstill:

Visual approach landing works a lot better during the day:

Touchdown ! But this is not time for celebration - if the site has too little ore, a relocation is in order...

3% is good enough ! We're staying. Margaritas for everyone !

[Jesrad]

Mining went just fine, although at Duna's distance the panels couldn't feed all 12 drills at once. I should have waited to unlock the Fuel Cells prior to launching, in retrospect.

Linielle was first to the ground:

Followed shortly by Naissa:

weeeeeeeeeeeeeeeeee

(You can't see it on the stills, but she's laughing maniacally all the way down)

And finally Jenming:

The refueling took 4 days, and refilling the ore one more day:

And then it was time to go visit Ike:

Circularizing at 60km altitude:

From then on, it's a pretty simple and cheap maneuver to Ike:

The Mighty Harvest of Science raged on around Ike shortly thereafter:

At that point, the crew was really fed up with collecting reports, shuffling assignments and resetting experiments, so they just laid back and enjoyed the view. Landing could wait a tad.

[Mister Dilsby]

Very nice! Having mined on Duna in several locations, yeah 3% is pretty good, especially for the Midlands. It tends to take me about 2 days to refuel the Hummlebee, but that's a much smaller ship--I can get away with a single drill, one small ore tank and four XL panels.

"Grand Tour Star" is a great name for your ship, and I wonder (since you speak French) if you intended the double meaning of "big tower" If I were flying it I might also nickname it "the flying caltrop"

Looking forward to seeing where the GTS visits next!

[Jesrad]

And then, it was time ! Linielle reluctantly got to the helm and set course for the very bumpy, grey and unwelcoming ground of Ike, 20 km below.

The trick to landing on Ike is to find a spot where there's not too much slope. That's harder than it sounds, especially if you want an easy, visual landing like on Duna: then, it needs to be flat, horizontal AND in one of the light-grey zone. The dark grey zones are too dark to see ground details well enough.

And if you end up headed for a dark zone, well, this little thing can save your bacon:

Linielle kept her eyes on the ground radar, Naissa kept hers on the altimeter, while Jenming stayed a hand on the main rocket's throttle lever.

"Ready !" Linie shouted across the cabin, as soon as the needle started moving. "Brace !" replied Jen as he applied full thrust.

"Mark !" continued Linie as soon as the needle passed 2000. That was the signal for Naissa to report the absolute altitude, and for Jen to cut thrust. "9-4-7-2 meters !". "We are go for landing, target 7-4-7-2 meters absolute ground altitude." Linielle confirmed. "I copy, 7-4-7-2 meters, mark" Jenming segued.

The team went with a slowdown at 7800 m for a slow, controlled descent over the last few hundred meters:

Everyone was tensely waiting for the unannounced impact with the ground, watching nervously the altitude needle drop slowly toward the estimated ground alt... and suddenly:

"I have visual !" cried Jenming. "It's faint but I can make out the ship's shadow on the ground !"

Both girls sighed with relief and glued themselves to the sole window port. They managed a finely-controlled visual approach:

*CRRRRRRRONK*

*Psshhhhhhhhhhffffff....*

*ClunkclunkclunkCLUNKCLUNK-*

"...w...what was THAT ?"

"Did we ... ? Tell me we didn't break something expensive !" said Naissa as she curled up into a ball.

Nah, nothing broke. But the Star flexed quite a bit as she came to a stop along the sloped ground. The clunking and thumping were from the SAS trying to righten her up futilely, batting the branches on the ground. They had forgotten to disengage stability augmentation along with the rocket thrust.

- - - Updated - - -

Somewhere on Kerbin, an accountant was doing the happy dance. Cha-ching !

Meanwhile on Ike - Jenming called dibs on flag-planting, and none of the girls contested because it was too dark out there for their taste.

The ore concentration turned out a bit above 2%. Besides, the landing had been terrifying enough that no one in the team would dare try their luck elsewhere. All the ore was converted to fuel, and all drills were deployed:

The refueling took enough day-night cycles that even Jenming finally got bored of playing "Munar Lander" on the onboard computer.

It was finally time to leave !

The ore was then convreted into more fuel, almost topping the tank once again:

There was just one last thing left to do... Finally, reluctantly, all three Kerbonauts gathered in the lab and faced the issue that would shape and change their future forever...

"Soooo...." Naissa started.

"So." Jenming confirmed.

"...where are we going next ?"

- - - Updated - - -

"Grand Tour Star" is a great name for your ship, and I wonder (since you speak French) if you intended the double meaning of "big tower" If I were flying it I might also nickname it "the flying caltrop"

I bow to your keen observation skills I initially intended to make a word-play on some for of "lighthouse" because of the shape of the piloting mast, but settled on Grande Tour since she was to go on a serial exploration of most planets and moons.

[Jesrad]

Dres for Success

"Gaaah it won't intercept either !" said a frustrated Jenming.

"If I fix another maneuver node I'll puke." was heard from Naissa, slumbered over the nav table, almost passed out in nausea.

"Guys, guys, now. So we have no injection window to anywhere, OK, alright I get it." Liniella added.

She paused dramatically for attention, and failed to get it. "What about we go nowhere instead ?"

"You don't mean..."

"Yes. Let's fly to Dres."

And dread was in the eyes of the Kerbals. For Dres, to the best of their knowledge, is simply the most atrociously boring rock a Kerbal ever hopes not to visit in his lifetime.

After converting my stash of ore from Ike while orbiting it, I noticed this strange thing: the fuel got into each branch after the other, isntead of spreading evenly. So the Star was completely off-balance. Good thing I did not attempt any maneuver yet.

So I moved all the LFO on the inside of the branches then circled it across the tips until it was pretty much evened out.

First attempt at Dres injection was... discouraging:

1926 m/s ? That cannot be right.

So Naissa took a hold of herself and replotted, this time further down and assuming a midway inclination correction:

Much better ! The crew launched in the dark as is usual for outbound transits:

The inclination and correction burn turned out to be a hefty 580 m/s, yikes. But that is why the Star has such a high fuel fraction, afterall. We knew all along we wouldn't get optimal transit windows.

Goodbye rust ! See you soon, ash !

[Nefrums]

That is a nice ship you have there!

You know that you can mouse-over the nodes and see the dV?

[Jesrad]

I know, but they disappear in screenshots if I just mouseover, so instead I try to remember to click them so they stay up. But then, any change in conic patch level vanishes them again. And 9 times out of 10 KSP thinks I'm clicking somewhere else (it tries to add a new maneuver node or set a new target instead).

[Ferdoni]

Love this thread!!

I'm very curious tough how you will manage Eve...

[Jesrad]

I'm sending a rover (more accurately, a huge mobile science base) to the surface of Eve at the same time, so Grand Tour Star will only get to check out Gilly. She will dip a branch in its atmosphere though !