The Mun and back Cheapskate Challenge

[ManEatingApe]

13 hours ago, Pds314 said:

Quick question/clarification for pod landings, does the pod need to survive or can you just jump out?

Good question - yes is the answer, the pod should survive. How it survives it up to you...parachute, propulsive braking, or some other cheap and cheerful solution

13 hours ago, camacju said:

https://imgur.com/a/CLhKjuV

263.5 funds

Nice entry, you even shaved 13 funds off the previous run.
You take first spot on the leaderboard that will be tough to beat!

13 hours ago, camacju said:

edit: Also why would the nuke clipping even change the risk of tailstrike? It's not even the farthest aft part in its stack

The trailstrike mention was a general comment about the difficulties introduced by the length of the nuke and not specific to your design which mounts the nuke ahead of the rapier inline.

Edited October 21, 2020 by ManEatingApe

[camacju]

@ManEatingApe I think you quoted yourself rather than editing the top post in the thread?

edit: whoops I didn't see you changed it

Edited October 21, 2020 by camacju

[camacju]

https://imgur.com/a/33qI4XY

@ManEatingApeI was wondering - I changed the plane design and managed to get the same lander into orbit for 175 funds worth of liquid fuel. Would I be able to simply add the lander's fuel costs from last mission, or do I have to fly it over again?

If I am able to add the lander's fuel costs, then the total cost would be 238.5 funds. There's still room for improvement (:

If not, then since the lander is definitely able to make it to Mun and back, and assuming I fly a little less efficiently and use all of the lander's fuel, then the total cost would be 239.2 funds

[ManEatingApe]

1 hour ago, camacju said:

@ManEatingApe I think you quoted yourself rather than editing the top post in the thread?

edit: whoops I didn't see you changed it

Yeah, had to fix it up. The new forum layout has switched the location of some UI elements around. The "edit" option has moved to a context menu and the "quote" is now where the edit used to be <sigh>

6 minutes ago, camacju said:

https://imgur.com/a/33qI4XY

@ManEatingApeI was wondering - I changed the plane design and managed to get the same lander into orbit for 175 funds worth of liquid fuel. Would I be able to simply add the lander's fuel costs from last mission, or do I have to fly it over again?

If I am able to add the lander's fuel costs, then the total cost would be 238.5 funds. There's still room for improvement (:

If it is exactly the same lander then I'm fine with that...but how about you iterate on the design and ascent profile for a while and see how low you can go?
I'd like to avoid a sequence of almost identical entries cluttering the thread.

Edited October 21, 2020 by ManEatingApe

[camacju]

The thing is, this is probably as low as I can reasonably go without messing around with partially loaded fuel tanks, at least with this design. I'll probably say that 238.5 is my final entry, unless I find  a significant way to improve costs.

[ManEatingApe]

3 minutes ago, camacju said:

The thing is, this is probably as low as I can reasonably go without messing around with partially loaded fuel tanks, at least with this design. I'll probably say that 238.5 is my final entry, unless I find  a significant way to improve costs.

Okey-dokey, updated your entry on the leaderboard with that cost.

[jinnantonix]

@ManEatingApe I am working on a craft for the re-usable category.  It is a two stage craft with a command chair, and both sections land on Kerbin intact.

• If I use a parachute, is that included in the recovered cost?
• Same for if I stage a fairing, do I also include the cost of the fairing in my score?
• Can I land anywhere on Kerbin, and get 100% recovered cost?

[camacju]

Service bay is the same mass as a fairing big enough to hold a kerbal/rocket, and a lot less draggy. I tried using fairing designs but they always had greater drag losses than the service bay - more than enough to overcome any cost savings I could get with the fairing.

[camacju]

I've tried a bunch of non-DLC designs. This is the closest one I could come up with that's remotely capable of going to Mun and back but jetpacking is involved. Those DLC fuel adapters are just too good, lol

[camacju]

https://imgur.com/a/Iy282kj

168.9 funds used. Looks like I found a way to significantly reduce cost lol

The breakdown is 72 funds used on the jet engine stage, 34.5 funds used on the first rocket stage, and 62.4 used on the lander stage. I'm still using more funds on the jet stage than any other, which suggests room for improvement by attaching a Wheesley engine for early slow flight.

Edited October 23, 2020 by camacju

[ManEatingApe]

13 hours ago, jinnantonix said:

@ManEatingApe I am working on a craft for the re-usable category.  It is a two stage craft with a command chair, and both sections land on Kerbin intact.

• If I use a parachute, is that included in the recovered cost?
• Same for if I stage a fairing, do I also include the cost of the fairing in my score?
• Can I land anywhere on Kerbin, and get 100% recovered cost?

To clarify things and keep it straightforward, "recovered cost" is whatever the "Mission Summary for <craft name>" dialog shows after you click the "Recover Vessel" button. IIRC parachutes are included in the cost even after deployment. To get 100% cost back you'll need to land on the KSC grounds. Otherwise the closer you land to the KSC the higher the percentage cost recovered.

Going forward I'm going to ask any entries in the recoverable category to included a screenshot of the F3 menu with the recovered cost.
This will keep things fair for all entrants.

7 hours ago, camacju said:

https://imgur.com/a/Iy282kj

168.9 funds used. Looks like I found a way to significantly reduce cost lol

The breakdown is 72 funds used on the jet engine stage, 34.5 funds used on the first rocket stage, and 62.4 used on the lander stage. I'm still using more funds on the jet stage than any other, which suggests room for improvement by attaching a Wheesley engine for early slow flight.

I like how you continue the push the envelope of Kerbal-in-a-can™️ designs. Can you include a screenshot of the recovered costs menu ?
As this is a rules tightening/clarification no need to re-fly the entire mission, I'm happy to accept screenshots of just the 1st and 2nd stage recovery.

Edited October 23, 2020 by ManEatingApe

[camacju]

ok uh that's quite unfortunate for me since I wasn't paying much (any) attention to where I recovered the stages, so the metric I was using for cost was just fuel cost.

@ManEatingApe Can fuel cost be the metric used? It's going to be a lower amount if I don't land at the KSC and now that I'm doing completely unguided reentries I don't want to have to aim all the stuff directly at KSC

Also I just realized that KSP doesn't give me the mission reports for recovery in sandbox mode so the only metric that'll be usable for me will be fuel cost

Edited October 23, 2020 by camacju

[camacju]

I'm working on another relatively large design change. It involves a two stage lander mounted sideways in a service bay using one ant engine and two oscar tanks.

The ascent profile is pretty much the same. Boost with a rapier, get into orbit with a spark and FLT-100.

The orbital maneuvers are different. I'm using a Mun assist to boost myself into an orbit with 1.5x the period of Mun. However the primary reason isn't delta-v savings this time since I've got more than enough margin to do everything normally. The reason for this is so I can get a free return trajectory that's also in a prograde direction relative to Mun's rotation. I drop one of the spent fuel tanks here and let it coast down to Kerbin, while doing the rest with the remaining ant engine and oscar tank. I haven't gotten to the actual Mun landing yet but I should be able to do it.

Total fuel cost so far:
63.92 funds for the jet stage
29.12 funds for the spark stage
17.77 funds for the first oscar tank

Maximum possible cost from here:
18.36 funds for the second oscar tank

Maximum total cost: 129.17 funds
I will probably finish the mission later today

Edited October 23, 2020 by camacju

[ManEatingApe]

3 hours ago, camacju said:

ok uh that's quite unfortunate for me since I wasn't paying much (any) attention to where I recovered the stages, so the metric I was using for cost was just fuel cost.

Any previous entries are grandfathered in, so no changes to the leaderboard.

3 hours ago, camacju said:

Also I just realized that KSP doesn't give me the mission reports for recovery in sandbox mode so the only metric that'll be usable for me will be fuel cost

There's a straightforward workaround - if you don't already have a suitable career save, then:

1.   Start a new career mode save
2.  Open the debug menu
3. Under "Cheats" => "Maximum", click each of the "Technology", "Facility", "Experience" and "Progression" buttons.
   (This is fine, since the challenge is not about completing career mode )
4. You now have a fully maxed out save ready for use, that will give you the recovery dialog.

1 hour ago, camacju said:

I'm working on another relatively large design change. It involves a two stage lander mounted sideways in a service bay using one ant engine and two oscar tanks.

I look forward to seeing this!

[jinnantonix]

On 10/23/2020 at 8:40 PM, ManEatingApe said:

To clarify things and keep it straightforward, "recovered cost" is whatever the "Mission Summary for <craft name>" dialog shows after you click the "Recover Vessel" button. IIRC parachutes are included in the cost even after deployment. To get 100% cost back you'll need to land on the KSC grounds. Otherwise the closer you land to the KSC the higher the percentage cost recovered.

Going forward I'm going to ask any entries in the recoverable category to included a screenshot of the F3 menu with the recovered cost.
This will keep things fair for all entrants.

Well that changes things somewhat  .  My idea was, like camacju's designs, to use a suborbital air-breather first stage and parachutes - but that is no longer viable.  So my design will be as follows:

• Stage 1:  Lightweight Kerbin to orbit SSTO, with stage 2 as payload dropped in KLO, land at KSC
• Stage 2:  KLO to Mun and back to KSC - ultra lightweight command chair craft.  Gimbals only. Propulsive landing.

I did some calcs around a Stage 2 being Apollo style leaving fuel tanks in Mun orbit or free return trajectory, but the extra weight of the docking ports plus the fuel costs for the rendezvous makes this of questionable value. 

Edited October 24, 2020 by jinnantonix

[camacju]

Well... Unfortunately I was too late to finish this mission before the rule change that pretty much breaks my whole mission (I think just the recovery penalty alone is way bigger than my fuel cost), but here is my mission that uses 128.85 funds worth of fuel.

https://imgur.com/a/NnpPUoJ

I could have maybe (and this is a big maybe) aimed the last three stages at the KSC but the first stage is a lost cause. At least my first submission with the SSTO and lander works. Honestly I could still pull off some optimizations that I've since made but it'll probably not be a very big difference.

This mission will probably be good as a lower bound though. A quick summary of the mission:
Boost with rapier until 1700 m/s
Get into an almost orbit with the second stage, and decouple to throw the lander into orbit
Get a Mun assist that gives us a second Mun encounter - a free return trajectory, to recover the spent oscar tank, and a better encounter in general.
The rest of the mission is very standard because I lost motivation to keep saving funds after this mission got borked.

Actually I don't know if this is a loophole but I might be able to make this thing work under the new system also.

@ManEatingApe Would it be within the spirit of the challenge to launch a recovery vessel with a claw, thereby achieving 100% recovery savings by bringing debris to the KSC? If so, I would like to submit this craft along with a design of such a craft. I'll demonstrate it working on land and water to prove that I could recover debris from anywhere on Kerbin given enough patience.

[Regor]

@ManEatingApe

This vessel originally costs 6,345, but 2861 were recovered, leaving a total of 3484 and has a total dv of 3315 m/s in atmo (but around 7000 in vaccum). It also houses a thermometer and has only 10 parts. The battery and solar panel exploded during entry but I think that is fine, as the rest of the vessel survived (this means that the descent angle and the survival of my kerbal was incredibly hard, as there was no SAS control left).  

 

However it should be noted that this for another challenge which had a challenged to include scientific equipment, so I added a thermometer. If you remove the (in this challenge) completely and utterly unnecessary thermometer (which wouldn't change anything because it is physicless), you would get it down to 5,435 . Because of this, I believe the cost of this mission should be 5,435.

https://imgur.com/a/Om4DiOI

Edited October 25, 2020 by mabdi36

[ManEatingApe]

6 hours ago, mabdi36 said:

@ManEatingApe

This vessel originally costs 6,345, but 2861 were recovered, leaving a total of 3484 and has a total dv of 3315 m/s in atmo (but around 7000 in vaccum). It also houses a thermometer and has only 10 parts. The battery and solar panel exploded during entry but I think that is fine, as the rest of the vessel survived (this means that the descent angle and the survival of my kerbal was incredibly hard, as there was no SAS control left). 
<snip>
If you remove the (in this challenge) completely and utterly unnecessary thermometer (which wouldn't change anything because it is physicless), you would get it down to 5,435 . Because of this, I believe the cost of this mission should be 5,435.

https://imgur.com/a/Om4DiOI

Welcome to the challenge! Re-using an entry from another challenge is a creative out of the box time saving technique. And since time is money...
I've added you to the leaderboard with the absolute cost of 5,435 (not including the thermometer) and the recovered cost of 3484.

Your poor Kerbal was clipped into the fuel tank. Some philosophers may disagree but I would consider the pilot to be an "functional part". This time only I'm ok to allow the entry (as I don't think this gave any major drag reduction or heat reduction benefit, but would ask that for any future entries that you don't make the pilot sit in the cryogenic liquid fuel and at least give them the luxury of being crammed into a service bay.
 

12 hours ago, jinnantonix said:

Well that changes things somewhat  .  My idea was, like camacju's designs, to use a suborbital air-breather first stage and parachutes - but that is no longer viable.  So my design will be as follows:

• Stage 1:  Lightweight Kerbin to orbit SSTO, with stage 2 as payload dropped in KLO, land at KSC
• Stage 2:  KLO to Mun and back to KSC - ultra lightweight command chair craft.  Gimbals only. Propulsive landing.

I did some calcs around a Stage 2 being Apollo style leaving fuel tanks in Mun orbit or free return trajectory, but the extra weight of the docking ports plus the fuel costs for the rendezvous makes this of questionable value. 

A suborbital air breather booster stage could still work with either some long range gliding capability (e.g boost-glide) or enough manuverability to turn around and get back to the KSC. A tiny fuel efficient helper engine such as a Juno could be useful with the either approach as a cheap range extender.

10 hours ago, camacju said:

Well... Unfortunately I was too late to finish this mission before the rule change that pretty much breaks my whole mission (I think just the recovery penalty alone is way bigger than my fuel cost), but here is my mission that uses 128.85 funds worth of fuel.

https://imgur.com/a/NnpPUoJ

I could have maybe (and this is a big maybe) aimed the last three stages at the KSC but the first stage is a lost cause. At least my first submission with the SSTO and lander works. Honestly I could still pull off some optimizations that I've since made but it'll probably not be a very big difference.

This is definitely worth an honorable mention as pushing the envelope of fuel (but not cost) efficiency.

10 hours ago, camacju said:

Would it be within the spirit of the challenge to launch a recovery vessel with a claw, thereby achieving 100% recovery savings by bringing debris to the KSC? If so, I would like to submit this craft along with a design of such a craft. I'll demonstrate it working on land and water to prove that I could recover debris from anywhere on Kerbin given enough patience.

That is some great creative thinking. It would absolutely be in the spirit of the challenge to fly a recovery mission as long as the costs of the recovery vessel are also included.
You would essentially be trying to be more cost efficient than the game's built in recovery penalty for distance.

Just to be clear - this would not necessarily have to be the same craft as the mission that goes to the Mun but any fuel costs used for part recovery would count towards the total mission cost. However I really think this has potential for designs that can't make it back (or near) to the KSC.

Edited October 25, 2020 by ManEatingApe

[Regor]

52 minutes ago, ManEatingApe said:

Welcome to the challenge! Re-using an entry from another challenge is a creative out of the box time saving technique. And since time is money...
I've added you to the leaderboard with the absolute cost of 5,435 (not including the thermometer) and the recovered cost of 3484.

 

@ManEatingApe It seems I have made an error... If we remove the thermometer from the recovery cost as well (with the recovered cost of the thermometer seen in the album),  I would have recovered 2572 funds, which would mean the overall cost of the mission was 5435-2572 = 2863 funds  

[vyznev]

1 hour ago, ManEatingApe said:

That is some great creative thinking. It would absolutely be in the spirit of the challenge to fly a recovery mission as long as the costs of the recovery vessel are also included. You would essentially be trying to be more cost efficient than the game's built in recovery penalty for distance.

Solar electric prop planes are allowed, aren't they?  

[ManEatingApe]

2 hours ago, mabdi36 said:

If we remove the thermometer from the recovery cost as well (with the recovered cost of the thermometer seen in the album),  I would have recovered 2572 funds, which would mean the overall cost of the mission was 5435-2572 = 2863 funds  

No worries, leaderboard updated.

2 hours ago, vyznev said:

Solar electric prop planes are allowed, aren't they?  

Most definitely!

Edited October 25, 2020 by ManEatingApe

[jinnantonix]

Here is my entry in re-usable category:  

Kerbal Space Program El Cheapo Mission to the Mun. Two stage craft: First stage uses Rapier engines to achieve LKO, then a lightweight lunar lander (with no reaction wheel or electrics, gimbals only!) completes the mission with Jeb planting a flag on the Mun and returning to the KSC.

Total cost in the SPH =43,631, with 41,434 and 988 recovered, leaving a total of 1,209   

With the changed rules, I don't think it is possible to beat the previous score on the leader board, but I had some fun with this anyway.

 

Edited October 26, 2020 by jinnantonix

[ManEatingApe]

2 hours ago, jinnantonix said:

Here is my entry in re-usable category:  

Kerbal Space Program El Cheapo Mission to the Mun. Two stage craft: First stage uses Rapier engines to achieve LKO, then a lightweight lunar lander (with no reaction wheel or electrics, gimbals only!) completes the mission with Jeb planting a flag on the Mun and returning to the KSC.

Total cost in the SPH =43,631, with 41,434 and 988 recovered, leaving a total of 1,209   

With the changed rules, I don't think it is possible to beat the previous score on the leader board, but I had some fun with this anyway.

 

Splendid spendthrift entry and video. 1,209 is an extremely respectable score.

I  really like the minmal lander. Using the drogue chute to save weight with a little propulsive help for the landing is a nice touch.

Edited October 26, 2020 by ManEatingApe

[camacju]

https://imgur.com/a/eDGYt8m

Instead of doing a full redesign with this lander I took it to Minmus and Gilly for 126.9 funds of fuel. I could probably do a Bop or Pol mission with this thing also.

[ManEatingApe]

2 hours ago, camacju said:

...<snip> I could probably do a Bop or Pol mission with this thing also.

You should definitely consider a low cost entry to the Ultimate Jool5 Challenge.

On 10/26/2020 at 10:09 AM, jinnantonix said:

...I don't think it is possible to beat the previous score on the leader board, but I had some fun with this anyway.

I feel there's considerable potential in your design for further costs savings. For example it cost a lot of fuel to accelerate the whole SSTO to orbital velocity in order to go around to the KSC, but another approach would be to turn around and go back, SpaceX style and let the lander circularize around Kerbin. This would save LF/OX at the cost of some extra liquid fuel to fly back through the atmosphere, but the higher atmospheric ISP of the Rapier is in your favour here.