Kerpollo with 30 parts

[Majk]

 

This is my take on the Kerpollo challenge in an attempt to finally visit all bodies in the Kerbol system.

A quick calculation suggests that I can have the whole science tree unlocked before Joolollo and Evepollo (maybe missing a couple nodes, but nothing unsolvable by Surface samples, EVA and Crew reports in the Joolian system, meaning I don't need to bring any science experiments on the later missions. I originally intended to do this in a career mode (without any contracts) instead of science, but trying to figure out how to do the Minmus mission with two command pods (there was no Mk2 pod yet, and I wanted to have both scientist and pilot present), all available science experiments, only 30 parts and limited funds seemed rather hard. It gave me another idea - let's just limit myself to 30 parts on each mission. Given that I'm fairly new to KSP, it felt at times like I've bitten more than I can chew. 

My settings are mostly hard difficulty with Science set to 100%, reentry heating to 120% and Kerbal G-force limits on. The challenge forbids using probe cores, and I interpret this as forbidding command chair builds. This means that the missions will not be very low mass.

I expected the part count limit to be a serious issue in the earlier missions due to the lack of large fuel tanks, but I was mistaken. The early missions even had things like heat shields and landing legs, which were simply too expensive in the later ones.

Kerpollo

After getting just enough science from the launchpad to unlock the first tier of tech tree, let's build an orbiter.

Spoiler

The first three missions weren't playing on Steam. This posed a challenge -- the Mac shortcut for screenshot contains a shift key, which controls throttle. Jebediah was almost stranded in orbit because of this. For Dres I switched to Steam, and now the screenshot hotkey just toggled aeroforces display.

Going home.

Some more KSC science is needed to enable Minmus mission

 

Minmuspollo

Spoiler

Minty!

Coming home. Toying with the part limit meant I forgot the parachute. Bob doesn't suspect a thing.

To add insult to injury, I was optimizing mass and instructed Bob to not pack his parachute.

Seriously, what?? How come I never seen anybody landing on Kerbin with just RCS jetpack? 

 

 

 

Munpollo

Spoiler

I can now unlock the whole fourth tier, but I choose not to do so. I want to avoid the docking port for this mission.

This is the only mission where I didn't need the full 30 parts (at the time of writing this, I still have Eve to conquer).

Bob's the Pilot.

First in the series of wonky flags.

Let's go home!

My favourite way to reenter - point radial out, and throw the engines below you. This way, you can watch them disintegrate.

Enjoy your heatshield -- the part count restriction will quickly make this a luxury.

We now know enough to go interplanetary.

 

Drespollo

Avoiding the docking port any longer is too costly, let's bite the bullet and accept the extra complexity in lander-orbiter design. I picked the closest single world target - Dres.

Spoiler

This is the last mission where a reaction wheel can be used. The part limit is fairly strict with the science payload and limited tech.

Boosters might not be the most weight efficient, but they certainly are parts-efficient at this stage.

This budget is looking really generous.

Bob is the first to set foot on another planet.

Why are all my flags falling down the second I plant them? This is so anticlimactic.

First docking in the campaign also means first piece of space junk left in orbit.

As a celebration of their amazing technological and scientific achievement, fireworks are planned!

Time to publish the acquired results in a peer reviewed journal. 

Dunpollo

Thanks to successful Dres mission, we now have a seismometer and variometer. These two experiments were one of the reasons I went to Dres first, as the atmospheric scan is quite juicy in terms of science.

Spoiler

The orbiter doesn't have any engine, it's just a lander can and a huge tank for refuelling.

This mission will be flown with Bob and Bill. An engineer is needed to repack the parachute and there is no room for a pilot. This also means that maneuver nodes can only be used in LKO.

Aerocapture at Duna was quite on point, only 5m/s burn was needed afterwards to lower apoapsis to Duna's SOI.

The problem with missing maneuver nodes posed an interesting challenge: how to encounter Ike? This problem solved itself as the second aerobraking pass put me on a collision course.

Bob is sad that the flags still topple.

Only a quick burn out of Ike's SOI, and we're undocking again.

The single parachute isn't sufficient to land without using any fuel, but it's close.

The landing was quite ugly, but I got it after few tries.

Delta-v reserves are getting thin, but there is still some fuel left in the orbiter.

Now kiss!

This should be enough to get home.

Obligatory fireworks. But hey, we're having a parachute. This is not something to get accustomed to!

That's a bingo!

Eelpollo

With all science experiments unlocked, it's time to go to Eeloo to collect another huge chunk of data.

Spoiler

 

Unlike other missions, this one features a relatively smaller spacecraft with a tiny lander. Quality of life improvements include a fairing to protect the delicate lander, which will be left in Eeloo's orbit.

This ascent profile might be a bit too shallow.

Eeloo is far away, but nothing a pack of NERV engines cannot do!

At last!

If you think there is no way this lander will topple, you overestimate my piloting skills.

BetterBurnTime is suggesting that some radial component is needed to avoid unscheduled disassembly. 

Click!

Sad flag. As always!

There is even time for a bit of a fun in this 7 year long mission!

Eeloo was fun, Val! Too bad you couldn't walk it as well.

We're left with more than 2000 m/s. Is this mission horribly over-engineered, or will this come to good use? 

Step 1: Put bread into toaster. Step 2: Set periapsis to 12 kilometers. 

Quick, call 999, we've got an emergency!

We're deep in the atmosphere, but still on an escape trajectory.

Second pass is considerably safer. No explosions this time, does this mission even count?

Exploding radioactive engines in the ocean is a totally normal thing to do!

Eeloo's high science multiplier means that we've got almost as much as from Duna and Ike combined.

Mohpollo

Moho was the only time this felt a bit grindy. Not much needed to be changed from the Eeloo mission.

Spoiler

Crew rotation put Jebediah on the mission.

Who cares about transfer windows? Let's just put periapsis between Moho and Eve, then burn at descending node, and carefully Hohmann the rest. This also meant that capture burn was less than 1000 m/s, well within NERV capabilities.

Bob instructed Jebediah on how to do all the science experiments himself and enjoyed some solitude in the highly eccentric orbit.

Jebediah did everything well, except he forgot to take a picture upon landing. Don't worry, the flag toppled as usual.

Do you have a good way of getting a randevouz from low orbit to a highly eccentric one? I typically need hundreds of skipped orbits to get a reasonable separation.

Bob started to have Gemini 4 flashbacks by now, but we're getting close after 23 days in orbit.

Not much fuel left, but we shouldn't be going nearly as fast as when we returned from Eeloo, right?

We're getting a good bend on the trajectory, this looks promising.

Again, we cannot afford any decouplers or heat shields in this 20 ton reentry module. We'll have to jump and use EVA chutes this time.

This concludes the techtree.

 

 

Joolpollo

The part count limit meant that a single lander has to be reused on all bodies. As this was my first Jool 5, I didn't have a good feeling for how much delta-v is needed for orbital maneuvers, so I budgeted 6000 m/s for everything in Jool SOI. I expected the orbiter to stay at fairly eccentric orbits with the exception of Tylo, where the budget was just too tight. I budgeted meager 500 m/s to brake when coming back to Kerbin.

Spoiler

The average part has more than 45 tons!

Majestic!

The ascent stage was sacrificed to Kraken.

The longest burn in the mission. It didn't end up very imprecise.

Capturing using Tylo gravity assist.

Our pilots' enthusiasm hasn't changed a bit!

Only 10 m/s more was needed to get a resonant orbit with Laythe.

Binary searching the correct aerobraking altitude. I wanted the orbiter to stay at the SOI edge to save fuel.

I typically plot a maneuver node at periapsis having desired magnitude. Then I can observe how much aerobraking is happening.

Binary searching the right deorbiting profile. 

Closer, but still no.

Here you can see the lander in all its beauty. Of course, I need to redo the landing at a flatter spot, this one cannot right itself at Laythe's gravity. The parachute is attached to the docking node on top, and will stay on the surface. This 300 kg saving is fairly substantial.

The upper stage uses two Twitch engines. However, I cannot stage just yet, the lower stage is needed on Tylo descent. Instead, the Kodiak engine dips into the upper stage tank. For this reason, the delta-V readout is misleading.

I needed to bring the orbiter a bit lower in order to redock.

Laythe was the most time consuming segment of the whole campaign. The lander was not very controllable on descent, fairly unstable on uneven surface and flippy on ascent. 2/10 would not fly again. I am happy to finally leave Laythe behind.

Tylo is easier to pilot, it just needs more raw power. As a result, the orbiter needs to bring the lander all the way to low orbit.

Again, looks perfectly sane to me.

Kodiak was discarded right before the touchdown. This wasn't strictly necessary, but was my original design before I added the ladder because of Laythe.

Valentina could plant a flag either.

I like how the screenshot succession doesn't capture the blood, sweat and tears that went into this docking. Only now I realised that the twitch engine doesn't have alternator, so from now on, the 50 electricity stored in the lander can needs to be sufficient for landing, ascent and docking. The orbiter can recharge the batteries only by burning fuel. As the whole ship was still fairly heavy, rotating it 180 degrees burned almost the whole battery. I solved this by enabling SAS for only a brief moment to give me the correct angular momentum, and then again to stop it from rotating.

 

The good thing is that I'm doing fairly well in terms of delta-v in the orbiter. This is due to two facts: first, I overestimated the cost of orbital maneuvers, and second, the payload size decreased substantially on the first two landings (about 10 tons on each). I started to think that using two of the largest Mk3 tanks for the NERV fuel was an overkill. This Vall transfer isn't very precise, but I figured it's not necessary to squeeze every little bit of fuel out of this.

Valentina has the honour for the second time in a row.

It looks like they're not even trying.

Another successful docking that definitely didn't take more than a single attempt.

I wanted to continue to Bop, but Pol was in a very nice spot, so I changed my plans.

I take that back, this was a horrible transfer!

Jebediah finally got it right! The proceeded to topple the lander.

Prepare to skip another hundred orbits to reunite.

The final landing will be done by Valentina.

This needs to be fixed.

Okay, which way is home? Did you bring a map?

First, let's go Tylo.

And then burn to lower periapsis all the way to Kerbin. The encounter is fairly bad, and a close fly-by would happen in 100 years.

Luckily a small correction burn at Kerbol periapsis and another one after passing orbit of Dres was enough to get to Kerbin one orbit later.

Definitely not going to aerocapture this monster. We need to reload.

That didn't work either, and we lost the engines.

Finally, after an over 2000 m/s burn, we're getting there. I need to work on my transfers from Tylo. Or perhaps squeeze a decoupler and a heat shield into the part budget.

Jeb and Val parted ways at orbit, with Valentina descending in the lander. The fuel tank exploded, but the can survived. After all, it's called a lander CAN, not a lander CAN'T.

Finally, a bath!

One orbit later, Jeb descends in his heavy orbiter. Hard to say what its terminal velocity is, but it definitely wasn't one that would allow any parachute to open.

Luckily, the EVA chute comes to the rescue.

 

Evepollo

Spoiler

It wasn't easy, but we're at 30 parts. The upper stages and orbiter are shown. It's even lighter than the Joolpollo ship.

The ascent stage are three Mammoth engines with a single S4-512 tank. This will be also used on Eve. The main bulk of the ship is inspired by Bradley Whistance's 10 part grand tour to everywhere. I didn't trust my piloting skills as much to land at a high altitude so I added an extra Mammoth engine. In order to be able to take off from sea level comfortably, I added a terrier upper stage.

There were three radially attached S4-256 tanks worth almost 2000 m/s. They are discarded in Kerbin's atmosphere, as the Mammoth engines are too weak to lift them at Eve's surface. These extra tanks are necessary, because unlike Bradley, I cannot land and refuel on Minmus.

A Mun gravity assist to get to Eve. The flyby lowered my Kerbol periapsis, but screwed the normal component, so it came about even.

This was my first trip to Eve, so I learned the hard way that aerobraking is not going to happen. Luckily, it was only 300 m/s burn to get a highly eccentric orbit.

After a couple very mild aerobraking passes I decided that my apoapsis was low enough for the fuel in Twin Boar to get me to Gilly.

Now you get to see what the fairing underneath the engine plate contains: a brand new ISRU set. You can actually mine mid flight and without deploying the fairing!

I found a flatter area to spend some months to refuel.

The tiny Gilly lander docks with the humongous mothership, or something like that.

Gazillion aerobraking passes later, the two modules separate and we are going in! 

The bottom fairing does amazing job in protecting all that delicate mining equipment.

My patience with the temperature gauges ended, and I burned more than 2000 m/s in panic.

Now we're white instead of fiery orange, looks good.

Great touchdown. Deploy the fairing, the drill ... and there is no ore. Ok, let's do this once more and hopefully we're lucky this time.

The second landing (I mean, the second successful landing) was a success, Jeb refilled the tanks to the brim.

We have liftoff. The mining equipment (ore tank, drill, ISRU and radiator) was attached to the engine plate "below" node. As such, it is discarded upon liftoff to shed some weight.

The middle stage was prone to flipping, but it had enough strength to right itself thanks to the large reaction wheel. Note that Twin Boar doesn't have any attachment nodes on the bottom. I solved this by slapping a RTG between the exhausts, and then offsetting a tiny decoupler to give it enough clearance. The RTG only weighs 80 kg, and gives some extra power to the reaction wheel during ascent. 

Looks like I'm gonna make it to orbit.

I needed a 1200 m/s inclination burn to get the randevouz. I could have just raised the apoapses of both vessels and do it for less, but I had 3000 m/s on the lander and 2500 m/s much on the orbiter, so I didn't need to optimise anymore. 

Valentina is happy to see Jeb again, but wondering where did he lose the rest of the ship.

Off we go!

Stand upright, they're taking a picture of us!

After a couple more aerobraking passes, the apoapsis fell below 70 km. Valentina undocked and burned prograde, because she wanted one more view of Kerbin. And also, I'm much more comfortable using one EVA chute at a time.

It's not without dangers on 120% heating. The rocket eventually flipped at around 1000 m/s.

But Jeb managed to eject in time.

Valentina's turn. The red temperature gauge is just the solar panel which probably wasn't necessary for the mission.

And just like that, this epic journey comes to an end.

 

Edited January 7, 2021 by Majk

[Vanamonde]

As someone whose builds always turn out 4+ times larger than they need to be, I admire your restraint.

[Spaceman.Spiff]

Dres was my first apollo style mission! I am impressed at your low part counts(I used mods and went waaaaaayyyyy overboard)

[Majk]

Low part count doesn't necessarily mean low mass. Wait until you see the Jool mission!

[Superfluous J]

22 hours ago, Majk said:

This posed a challenge -- the Mac shortcut for screenshot contains a shift key, which controls throttle. Jebediah was almost stranded in orbit because of this. For Dres I switched to Steam, and now the screenshot hotkey just toggled aeroforces display.

If you hit F1 it takes a screenshot in \[your ksp dir]\screenshots\

Otherwise, yeah I know how that works. My record button (F10) used to cycle the heat display, so I'd randomly have it on or not depending on exactly when and how many times I'd started and stopped recording

22 hours ago, Majk said:

Boosters might not be the most weight efficient, but they certainly are parts-efficient at this stage.

I'm enjoying so far seeing you make choices based on the number of parts and not the mass of the ship. Great examples of, as you so aptly put it *-efficiency. The word "efficiency" really doesn't mean anything on its own without a clarifier.

22 hours ago, Majk said:

how to encounter Ike?

...a question I've never needed to ask. In my space programs, I don't encounter Ike. Ike encounters me.

So far so FANTASTIC. Great read and a great set of missions. Can't wait to see how you tackle Eve with 30 parts. I'm pretty sure my lifters off Kerbin for my Eve ships have more than 30 parts.

22 hours ago, Majk said:

Do you have a good way of getting a randevouz from low orbit to a highly eccentric one? I typically need hundreds of skipped orbits to get a reasonable separation.

Basically put a maneuver right after periapsis and set it to burn up almost to the target's orbit. Ideally that will give you encounter markers that you can tweak to match up on the very next pass around. It's been several versions since I've done this and I don't know if it still works exactly that way (and some of my trips to Minmus make me question how they display information these days) but on paper it should work just fine.

 

[Majk]

Eve is done. I couldn't do it without ISRU and I also needed inspiration from Bradley Whistance's Grand Tour design, but it's over!

[Superfluous J]

On 1/4/2021 at 3:50 PM, Majk said:

The second landing (I mean, the second successful landing)

Welcome to Eve

Great mission and great report. I'm on my phone right now but I'll put you on the winner board next time I'm on my computer!

[king of nowhere]

Good job!

I was going to ask why you burned your tanks on reentry since you still had 2000 m/s available to rocket brake some more, but i realized I'm not the only one who's overly optimistic on aerobraking. I feel i found a kindred soul

[Majk]

I always try to do the smallest capture burn possible, so that I can get a good understanding of how much I actually need in order to minimize future designs. Plus the reentry fireworks are fun to watch!