Build the cheapest fully reusable heavy lifter with 3 cores (Falcon Heavy and Delta IV Heavy style) that's capable of 50t of payload to LKO

[Thundrevv]

I will first check submissions on 10-05-2022 at 15.00 GMT (UTC), and probably every day at that time. You can submit entries earlier, but I probably won't be able to look at them before 15.00 because of school/other responsibilities.

Proposed by u/AutomaticDoubt5080 on r/KerbalSpaceProgram

Submitions must include screenshots/videos of every launch phaze (liftoff, booster sep, booster recovery, core sep, core recovery, upper stage reentry, upper stage recovery) and a screenshot inside the VAB

Rules:

1. Central core must be Size 2 (2.5m)
2. Must have three cores. Cores do not have to be the same size;
3. It must be fully reusable, second and later stages included;
4. Must not be an SSTO;
5. Can be both remote-controlled and crewed;
6. No cheats (Kraken drive, Alt-f12 menu, KAL glitch etc.).

Every type of recovery is valid. You will, however, get extra points for propulsive landings.

Mods that count as stock:

• Visual (AVP, EVE, Scatterer, Parallax, ReStock etc.);
• Information (Kerbal Engineer, Trajectories etc.).

Mods that count as modded:

• Part mods (NFT, ReStock+ etc.);
• Autopilot mods (MechJeb);
• ANY MODS THAT CHANGE GAME DYNAMICS, ADD PARTS, CHANGE PHYSICS etc.

MODDED PARTS ARE ALLOWED AS PAYLOAD

Sorry if this is put together poorly, I'm not very skilled at making posts.

Point table:

FIRST STAGE:

Parachute (ocean) [20p]

Propulsive (ocean) [50p]

Parachute (land) [60p]

Propulsive (land) [75p]

Propulsive (LaunchPad) [100p]

Parachute (LaunchPad) [125p]

Propulsive (Drone ship) [150p]

Parachute (LaunchPad) [175p]

 

SECOND AND LATER STAGES:

Parachute (ocean) [30p]

Propulsive (ocean) [70p]

Parachute (land) [80p]

Propulsive (land) [100p]

Propulsive (LaunchPad) [150p]

Parachute (LaunchPad) [175p]

Propulsive (Drone ship) [200p]

Parachute (Drone ship) [250p]

Drone ship-an object in the ocean, put there by you. Can be cheated into position, but must not move during landing

 

Stock rank list:

Rank                    Username                    Points                   Price

1                             Thundrevv                   50                            205 420

1                             QF9E                              3.260                      70555

2                              swjr-swis                      1.642                    133 406

 

Mod rank list:

Rank                   Username                   Points                   Price

 

Rank is calculated using average of points and price, at the rate of points * 1000 / price.

 

My (stock) take. I used ReStock+ for dummy payload, not the craft itself. 

Edited May 16 by Thundrevv

[Autochrome]

What amount of points would it count if you landed the boosters by wings on the KSC Runway or the ocean?

[Thundrevv]

13 minutes ago, Autochrome said:

What amount of points would it count if you landed the boosters by wings on the KSC Runway or the ocean?

Well, landing is a landing. It makes sense to use landing legs, or other parts to serve as it. Landing on the runway would be 90% of LaunchPad points   and i am not sure about the end of the question

 

e: not sure as in i dont understand the question. the ocean part

Edited May 9 by Thundrevv

[Autochrome]

47 minutes ago, Thundrevv said:

e: not sure as in i dont understand the question. the ocean part

When you separate the boosters, you descend back into the atmosphere with wings on them and glide gently into the ocean.

[BlaZe119]

Is using FMRS allowed?

[Forked Camphor]

Just out of curiosity, why is MechJeb not allowed? Meaning, what advantage gives to this challenge in question?

[Autochrome]

11 hours ago, Forked Camphor said:

Just out of curiosity, why is MechJeb not allowed? Meaning, what advantage gives to this challenge in question?

It can land your boosters back at the KSC or the ocean without any problems, making this not really a challenge with it.

[Forked Camphor]

12 minutes ago, Autochrome said:

It can land your boosters back at the KSC or the ocean without any problems, making this not really a challenge with it.

Oh, do you mean the "Landing guidance"? It never worked well for me or I never configure it correctly, on Kerbin it doesn't take into account the atmosphere (Or maybe it does and is FAR the problem), and on airless bodies it doesn't take into account terrain height differences making you crash spectacularly on the sides of craters and mountains, so I mainly use SSAS for everything.

Anyway, thanks for the answer

[Thundrevv]

15 hours ago, Forked Camphor said:

Just out of curiosity, why is MechJeb not allowed? Meaning, what advantage gives to this challenge in question?

It is allowed, but that launch would count under the "modded" ranklist

18 hours ago, BlaZe119 said:

Is using FMRS allowed?

Yes

19 hours ago, Autochrome said:

When you separate the boosters, you descend back into the atmosphere with wings on them and glide gently into the ocean.

Uhhhh.... let's count that as Propulsive because you are controlling the rocket's descent

Edited May 10 by Thundrevv

[DeadJohn]

On 5/9/2022 at 2:00 PM, Thundrevv said:

My (stock) take. I used ReStock+ for dummy payload, not the craft itself. 

You used the Stage Recovery mod. That fits your definition of modded, not stock.

In order to do this challenge stock, you would need to drop the 2 side cores moments after liftoff, so they can land by parachute before being deleted when the central core passes physics range.

[Autochrome]

5 minutes ago, DeadJohn said:

You used the Stage Recovery mod. That fits your definition of modded, not stock.

In order to do this challenge stock, you would need to drop the 2 side cores moments after liftoff, so they can land by parachute before being deleted when the central core passes physics range.

Read the part where it states the mods that are considered "modded". It is only those mods that are considered in that category because the challenge would be impossible "stock".

[DeadJohn]

1 hour ago, Autochrome said:

Read the part where it states the mods that are considered "modded". It is only those mods that are considered in that category because the challenge would be impossible "stock".

I agree that the top post definition of stock (only visual and information mods allowed) makes the challenge near-impossible. "MODS THAT CHANGE GAME DYNAMICS, ADD PARTS, CHANGE PHYSICS etc."  count as modded. Stage Recovery and FMRS definitely do more than visuals and info.

There's a disconnect. Either the example screenshot is not stock, or the definition of stock vs modded needs revision.

[Thundrevv]

16 hours ago, DeadJohn said:

You used the Stage Recovery mod. That fits your definition of modded, not stock.

In order to do this challenge stock, you would need to drop the 2 side cores moments after liftoff, so they can land by parachute before being deleted when the central core passes physics range.

Fair enough. While testing the craft I did control the boosters, and for the final screenshots it didnt seem necessary

I will include screenshots of landing when i boot KSP up later today

 

14 hours ago, DeadJohn said:

I agree that the top post definition of stock (only visual and information mods allowed) makes the challenge near-impossible. "MODS THAT CHANGE GAME DYNAMICS, ADD PARTS, CHANGE PHYSICS etc."  count as modded. Stage Recovery and FMRS definitely do more than visuals and info.

There's a disconnect. Either the example screenshot is not stock, or the definition of stock vs modded needs revision.

I said in another reply that FMRS is allowed

[sevenperforce]

I've put together a three-core lifter with all stages recovered that comes in at 89,525 total funds (not including the 50 tonne payload).

I have propulsive recovery of the boosters and second stage at the launch site, and I have downrange land-based propulsive recovery of the center core booster, which should be 450 points added. I've tested all the parts separately but haven't flown the whole mission yet for screenshot purposes.

The scoring business is a little tricky -- I'm not sure your scoring metric is well-optimized.

[QF9E]

I'm not sure I fully understand the scoring.

First off, there's two different scores for "1st stage parachute (launchpad)", at 125 and 175 points. I suspect the second of these should read "1st stage parachute (droneship)".

Secondly, I don't quite understand the score of the OP example mission. The OP mentions that their mission is worth 50 points, and it lands both boosters, the core and the upper stage in the ocean. Did you perhaps forget to count points for one of the stages, or is the intent of the challenge that you do not score any points for landing the boosters, as both Falcon Heavy and Delta IV Heavy count the core stage as their 1st stage?

Thirdly, and assuming you do get points for landing the boosters, do you get points for each booster separately, or for both boosters at once? If the latter, what if I simulate being one dronship short and land one booster on a droneship and the other one in the ocean?

And finally, since you score points for every stage (except possibly the boosters, as discussed above), could you simply build a rocket with lots of stages to optimize your score?

 

One other question: is it allowed to save the game at stage separation, and load that savegame afterwards to switch to the discarded stage and land it?

[swjr-swis]

1 hour ago, QF9E said:

One other question: is it allowed to save the game at stage separation, and load that savegame afterwards to switch to the discarded stage and land it?

This one I wondered too. It's the only way to make a full recovery including side boosters happen in a pure stock game, and how I was attempting to make an entry for this. Still not easy to make happen, but not entirely impossible anymore... IF loading a save point is allowed.

[Thundrevv]

2 hours ago, QF9E said:

I'm not sure I fully understand the scoring.

First off, there's two different scores for "1st stage parachute (launchpad)", at 125 and 175 points. I suspect the second of these should read "1st stage parachute (droneship)".

Secondly, I don't quite understand the score of the OP example mission. The OP mentions that their mission is worth 50 points, and it lands both boosters, the core and the upper stage in the ocean. Did you perhaps forget to count points for one of the stages, or is the intent of the challenge that you do not score any points for landing the boosters, as both Falcon Heavy and Delta IV Heavy count the core stage as their 1st stage?

Thirdly, and assuming you do get points for landing the boosters, do you get points for each booster separately, or for both boosters at once? If the latter, what if I simulate being one dronship short and land one booster on a droneship and the other one in the ocean?

And finally, since you score points for every stage (except possibly the boosters, as discussed above), could you simply build a rocket with lots of stages to optimize your score?

 

One other question: is it allowed to save the game at stage separation, and load that savegame afterwards to switch to the discarded stage and land it?

Boosters are counted, it wasn't thinking really straight when I posted this

 

yes, quicksaving and quickloading is absolutely allowed. As in: Drop booster, F5, land booster, F9, get to orbit

[swjr-swis]

On 5/9/2022 at 8:00 PM, Thundrevv said:

Rank is calculated using average of points and price, at the rate of point:price=1:1 000

Looking at this more closely now: it favours building the most expensive lifter possible - building cheaply would just bring the average down.

Alternative: points * 1000 / price. This would result in a score range between 0.5 - 5.00 or so, higher being better (high points and low price).

 

This is assuming points scoring for 2x side boosters, 1x core, 1x extender as a maximum. @QF9E 's question about additional stages also getting points is very valid.

Edited May 13 by swjr-swis
miscalculation of score range

[camacju]

The challenge seems to emphasize reusability. Given this, would cost be determined before or after recovery? This would affect what the optimum strategy is

[swjr-swis]

@Thundrevv Test payload of exactly 50 t (inert), feel free to add to the OP for standard use by everyone: https://www.dropbox.com/s/ydxqmh6p4bpk01q/00000-50t.craft?dl=0

Spoiler

 

Also, a first entry to get things started, since no one else has submitted anything yet.

I'm going for a pure stock entry, no mods or DLC at all. Intended to land all stages with parachutes on drone ships, since that's the best scoring option. Lifter is 2x side boosters, 1x core stage, 1x extender+cabin, with the core stage and side boosters being almost identical. Complies with all stated rules as of the moment of this posting:

1. Central core is Size 2 (2.5m)
2. Has three cores, same size.
3. It is fully reusable, second and later stages included (with exception of the fairing and engine shrouds, but that's standard in such challenges, even if not explicitly stated).
4. It's obviously not an SSTO, or it wouldn't comply with rule #2.
5. It can be both remote-controlled and crewed. Recorded run is with crew, but all stages including the extender have a probe core and comms for full remote capability.
6. No cheats (Kraken drive, Alt-f12 menu, KAL glitch etc.).

Since it's pure stock, all recovery is done through savefile reloading, as permitted by OP. Note though that it is necessarily done in reverse order, due to the time-critical path to circularize the payload first.

 

WIP context for the curious:

Spoiler

A few test runs have shown the lifter to perform very predictably. This first entry confirms all stages are fully recoverable on land or sea, even when trajectories don't go entirely as planned. I just need to follow a pretty strict procedure and do all the steps at the right timings to get all stages on the -still to be deployed- drone ships. Perhaps more importantly, KSP needs to behave consistently between re-loads of save points. More attempts to follow in separate postings.

As designed so far, the cabin is a bit of dV waste if it's going to be launched uncrewed, but I didn't know how else to comply with rule #5 'can be both remote-controlled and crewed'. Also, it's not min-maxed yet: you didn't specify 'LKO' so I interpreted it as a range and gave it enough dV to put the payload even in polar and/or higher-than-absolute-minimum orbits if so desired. I think my payload will end up around 100-150 km anyway - to get trajectories for all stages that end in water (drone ships!) and also give me enough time margin to switch between the stages for individual recovery.

It'll probably be weekend, or later, before I get enough uninterrupted time to get a successful run with drone ships on record. Potentially, with the scoring I suggested before and nailing all landings, this could max on a 6+ score. Could get even a bit better if I remove excess fuel and swap for some cheaper parts, but right now I'm allowing myself plenty of margin just to get a successful run in.

 

So my entry then: the FRL3C50T-B, recorded on a minimum-score successful run, all parts recovered undamaged. This was just aiming to recover everything as the challenge requires, no drone ships yet.

Scoring for 2x side boosters on water (2x 20p)+ 1x center booster on land (1x 80p) + 1x extender stage on land (1x 80p) and price of 121799 funds (payload cost excluded):

• by the original OP method: (2x20 + 1x80 + 1x80) + (121799 / 1000) / 2 = 160.8995
• by my suggested alternative calculation: (2x20 + 1x80 + 1x80) * 1000 / 121799 = 1.642

Pictorial evidence of craft, flight, payload delivery, and individual recovery of all stages:

Spoiler

Assembled craft in VAB

Price of lifter minus test payload -> 133406 - 11607 = 121799 funds. The 3x launch stability enhancers (600 funds) are not strictly part of the craft, but I'm counting them anyway as they're required for a good launch.

 

Spoiler

Lift off up to payload delivery

Full assembly on the launch pad.

Lift off and switching SAS to prograde at 30 m/s. Not the most dV-optimized ascent, but allows plenty of margin to switch back to the individual stages.

Engine cut-off and side booster separation. Savefile #1 created.

Center booster relighted to raise Ap to 130 km target.

Extender stage burning to circularize, after center booster was emptied and staged off (and savefile #2 created, missed making a screenshot of that).

Engine cut off at target orbit.

Test payload of 50T delivered to 131x130 km LKO. Savefile #3 created.

Confirmation of payload delivery.

 

Spoiler

2x side booster recovery (on water) - savefile #1 reload

Side boosters empty and on reentry path.

Notice the boosters continue on a very parallel path. This will be key when we aim for a drone ship landing. Notice also I failed to correct the asymmetrical rotation this time.

Chutes deployed. Boosters ended up 1.3 km apart, due to drag differences caused by 180 degree rotation at atmosphere reentry. Even so they stayed within physics range all the way.

Switched to the booster that was splashing down first, to allow for a quick recovery procedure.

First side booster recovered.

Switching to side booster 2

Side booster 2 recovered. The slight price difference is caused by the distance-to-KSC calculation, 85.0 % vs 85.1 %. Both boosters were fully recovered, no parts damaged.

 

Spoiler

Center booster recovery (on land) - savefile #2 reload

Center booster empty and on a return trajectory outside the atmosphere.

Contact with the atmosphere.

Just past the hottest moment of reentry.

Chute deployment.

Touch down on a manually enforced slight incline, so the chutes stay open until fully horizontal.

No damaged parts. I remembered to screenshot the F3 screen this time.

Recovery summary of center booster.

 

Spoiler

Extender stage and crew recovery (on land) - savefile #3 reload

Crew waiting patiently in orbit after delivering payload. Slightly lower Pe is due to payload separation.

Atmosphere reentry after lowering orbit to 70x30 km (Pe probably needed to be 40km for a better trajectory).

Can no longer hold prograde, flipping. Could use some optimization to help it stick to prograde.

KSC in sight. Coming in fast due to heavy fuel load. Also could do with optimization.

Chute deployment after burning off most fuel to lighten the craft. Some fuel spared for a final braking burn just before touchdown.

All parts and crew safe on the ground.

Extender stage recovery summary.

 

P.S.: This design is 'no rights reserved, free to do as you please with it' as far as I'm concerned. If it gives any other entrants ideas for improved versions, you have my blessing to tinker away and enter your result as a competing entry. The craft file is linked here for anyone to try it. I just want to see a successful landing of all stages on drone ships, by anyone - fair play if you happen to succeed before I do, because I have limited free time and will take a while to get it.

 

Edited May 13 by swjr-swis
craft link, score calculations corrected

[Thundrevv]

@swjr-swis

Your entry is valid, and I'm going to use your point system

10 hours ago, camacju said:

The challenge seems to emphasize reusability. Given this, would cost be determined before or after recovery? This would affect what the optimum strategy is

Cost is what the rocket costs in VAB. So, before recovery

[QF9E]

I don't think this will gain me the top spot in the challenge as SRBs don't lend themselves to pin-point landings, but I like flying solids, so here goes. The Clydesdale Heavy:

A Clydesdale core and two Clydesdale boosters. The configuration was studied in real life by Boeing as the SRB-X.

Spoiler

Booster separation. I am flying North as this ensures that the boosters land on land rather than water.

Booster landing. The other booster can be seen landing in the distance.

 

Spoiler

Core separation. The rocket is already flying at orbital speed by this point.

Core re-entry over Kerbin's night side. The core completes about half an orbit, over the North pole.

Core splashdown

 

Spoiler

Payload deployment

Upper stage re-entry

Upper stage landing

Cost of the rocket: $80 005. Points:

• 2 booster parachute landings on land: 2 x 60 = 120 points
• Core parachute landing in the ocean: 30 points
• Upper stage parachute landing on land: 80 points.

Total: 230 points. With @swjr-swis's scoring system, my total score becomes 230 * 1000 / 80005 = 2.875.

Edited May 14 by QF9E

[Hotel26]

On 5/13/2022 at 4:37 PM, swjr-swis said:

they stayed within physics range all the way

I bumped my physics range up to 5km some time ago and have a) experienced no problems and b) do like that I can see vessels approaching/receding from/to a dot without that uncanny materialization/dematerialization effect.

Settings are in ./Physics.cfg:

Spoiler

VesselRanges
{
    prelaunch
    {
        load = 5000
        unload = 6000
        pack = 350
        unpack = 200
    }
    landed
    {
        load = 5000
        unload = 6000
        pack = 350
        unpack = 200
    }
    splashed
    {
        load = 5000
        unload = 6000
        pack = 350
        unpack = 200
    }
    flying
    {
        load = 5000
        unload = 50000
        pack = 25000
        unpack = 2000
    }
    orbit
    {
        load = 5000
        unload = 6000
        pack = 350
        unpack = 200
    }
    subOrbital
    {
        load = 5000
        unload = 50000
        pack = 10000
        unpack = 200
    }
    escaping
    {
        load = 5000
        unload = 6000
        pack = 350
        unpack = 200
    }
}

 

Edited May 14 by Hotel26

[swjr-swis]

47 minutes ago, Hotel26 said:

I bumped my physics range up to 5km some time ago and have a) experienced no problems and b) do like that I can see vessels approaching/receding from/to a dot without that uncanny materialization/dematerialization effect.

Settings are in ./Physics.cfg:

Thank you for reminding me of this one; I keep forgetting to do this again for every KSP instance. Undoing the frustrating editor offset limits, this, and lowering kerbal respawn to 5 mins (more than enough to pull themselves together after a crash. Back to work, I have craft to test!). Well, that and the ISAIDNOCAMERAWOBBLEDAMMIT! portrait setting (CAMERA_FX_INTERNAL = 0) that newer KSP versions no longer honour...

[Thundrevv]

3 hours ago, QF9E said:

I don't think this will gain me the top spot in the challenge

You actually are No1 currently, probably because you used SRBs, which tend to be cheaper