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Somewhat relevant: some time ago, as a part of a collaboration series, I delivered 240 tons (24,000 units) of ore from Eve to a station in Munar orbit.
 

 

Edited by EvermoreAlpaca
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Not quite what I'm looking for, but impressive nonetheless. I'm a bit surprised that the heatshields work so well, I tend to have problems with the craft not staying behind it -- typically I have to use heatshields at both ends. And even after watching it three times I don't understand how you get clear of them without wrecking your craft.

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The only thing they impact are the Mammoth engines, which are very robust.

And yes, I do realize this isn't an exact match, but figured folks working on their own missions might find it interesting =)

Edited by EvermoreAlpaca

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I have successfully completed the Eve Ascent Vehicle, capable of launch from sea level, and tested all key aspects of the mission.  The EAV just needed a bit of patient R&D work, choosing the right combinations of LFBs and Mammoth engines.  I am sure I can make this cheaper by trimming back on the finer points, but its good enough for a start.  Mission is underway.  

Mission Update:  Successfully refuelled on Minmus and transited to Eve.  Orbiting Eve now aligned with Gilly, Return craft is separated, and ready to land the EAV.  Just need to find a site with ore at <300m  altitude.  I just realised that I accidentally forgot to jettison 538 units of excess ore on Minmus.  I still easily made Eve orbit with fuel to spare by using aero-braking.

Update 2:  EAV landing and refuel, launch , rendezvous and Gilly ore delivery complete.  Currently in high Eve orbit waiting on window to Kerbin transit.

Update 3:  Mission completed, see below.

KIJK2m9.png

Final craft <$1M funds.

 

 

 

Edited by jinnantonix
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Mission was completed as follows:

  • All stock parts, vessel cost = $973,120
  • Engines used:
    • Stage 1 (Kerbin Launch):  2 x Mammoth
    • Stage 2 (Eve Launch):  4 x Mammoth + 8x Twin Boar + 8 x Vector
    • Stage 3 (Eve Orbit): 8x Vector (reused) + 8x Terrier
    • Stage 4 (Return):  8x Terrier (reused) + 2 x Twitch
  • No mods used in the mission.  HyperEdit and MechJeb were used during testing.
  • Crew :  Bill Kerman (engineer) for EAV (Eve Ascent Vehicle) with mining rig, and Val Kerman (pilot) for rendezvous of RV (Return Vehicle) with EAV/ore in Eve orbit.  No antennas used.
  • Landing site on Eve, altitude = 162m.  EAV was tested successfully at sea level

The most interesting part of the mission was the Eve orbital strategy.  It was important to complete the orbit in the same direction and plane as Gilly.  This required the craft approach Eve, decelerate to just within Eve SOI, warp up to Ap, burn retrograde to zero speed relative to Eve, then burn prograde into an orbit in the same plane as Gilly and Pe ~78km altitude for aerobraking.  There was enough fuel to circularise the orbit after only just one aerobrake manoeuvre.   After entering low Eve orbit, the RV (return vehicle) separated ready to burn straight to Gilly without any wasteful normal burn.  When the EAV/ore reached orbit it was slightly out of plane, but had just enough fuel to adjust and align in the same plane as the RV and Gilly.  The return vehicle then manoeuvred within the plane to rendezvous and dock with the EAV/ore.

By far the most challenging part of this project was building a low cost EAV that made low Eve orbit with enough fuel to rendezvous with the RV, and was in a configuration that was stable during descent so landed safely and reliably – I think this is a problem with some of the other ascent vehicle designs posted here.  The heat shield configuration (4 at top and 4 at bottom) required a lot of R&D, especially working out how to eject the shields without the craft exploding.  The key was using just the right number of chutes to slow the craft for decoupling the lower shields, and using an engine burn to get clear.

I am certain that it is possible to do this mission at a lower cost. I already have a few ideas on how to build a cheaper EAV.  Also the RV was a bit over-designed, had excess fuel, I didn’t even need any aerobraking to decelerate to low Kerbin orbit.   

Looking forward to seeing other entries.

 

Edited by jinnantonix
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Congratulations for being the first to complete this challenge!

I'm a bit torn now. One the one hand, there is considerable room for improvement, as you point out yourself. Then again, 1 million is already quite respectable -- the benchmark contract that spawned this challenge would pay 2.7 million all told, after all. And unlike aeroboi or myself, you've been willing to show your hand and, you know, actually do this. On the financial side, contracts that are never begun pay the worst.

Participation in this challenge is so low because it is hard. Also tedious and un-rewarding. Eve is hard enough as it is; as the saying goes, the place is littered with the debris of lifters that were almost good enough. Optimizing for cost (or part count or delta-V or whatever) compounds the effort. People looking at a finished mission video see a there-and-back flight like any other, it's not obvious how much planning and frustration went into making it.

23 hours ago, jinnantonix said:

The most interesting part of the mission was the Eve orbital strategy.  It was important to complete the orbit in the same direction and plane as Gilly.

This can be done a bit easier if you see to it that your incoming PE aligns with an AN/DN. Capture at PE as usual and -lo and behold- the AP will align with the opposing node. The actual angle barely matters, plane changes at a highly eccentric AP are dead cheap. I think I've done 30° for 50m/s or thereabouts.

 

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The thought of lifting anything heavier than a Kerbal from Eve's surface always terrified me, so this challenge formed part of my therapy :confused:

Here's a 4 x Mammoth, 4 x Twin-Boar, 1 x Rhino craft, costing a total of 390,000 funds.

ULgbsFl.png

The Rhino may seem an interesting choice, the rationale behind the decision was that significant parts of this mission required high dV vacuum maneuvers, and the Rhino provides both a good ISP of 340 and a good TWR for such a large craft.

Mission profile was similar to @jinnantonix's entry:

  • Single stage to Minimus surface
  • Refuel and transfer to low Eve orbit
  • Leave behind a fuel reserve (actually a tiny self contained spacecraft with a command chair, Spark and a reaction wheel)
  • Descend to the surface, mine ore, return and rendezvous with fuel reserve.
  • Transfer to Gilly

There were some differences:

  • Propulsive braking: I didn't bring any heat shields, instead using the engines to slow down to a survivable 1,500 m/s in Eve's atmosphere.
    (I did use parachutes for the landing, my fuel capacity and piloting skills were not up to the task of a pure propulsive landing)
  • 0° orbital inclination: Anything other than 0 degrees inclination makes orbital rendezvous tricky, especially on Eve where the cost of inclination changes are so very very high. By keeping everything exactly on the equator I was able to rendezvous with the fuel reserve for only 50 m/s dV and then dock for about the same again.
  • A transfer orbit and insertion burn to Gilly, intersecting at the ascending node was only 1,550 m/s.

Some findings relating to costs:

  • Structural pylons are much cheaper than other decouplers, and handy to boot as their size keeps the tanks apart.
  • The Size 3 -> Size 2 Kerbodyne adapter is silly expensive.
  • I was a little extravagant with 4 x Gigantors (at 3k a pop) and a full size drill and ISRU, mainly 'cos I'm impatient. Using fewer panels and the smaller drill and converter could have saved some funds at the cost of some game time.


Highlights:
Landed on Minimus's surface

KomITXM.png

Landed on Gilly - no one said anything about getting the crew back! At least they won't be b-ore-d....I'll get my coat.
6oVJi0n.png


Full album link (including Eve ascent details)

Craft file

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Whoa, now we're talking business. Though, ahem, minor nitpick: you seem to have stranded your crew on Gilly, while I want a safe return. (checks front page) OK, I didn't put much emphasis on that point... then again I didn't expect that anyone would leave them on Gilly and call it a day.

I don't want to force you to start over from scratch; even when including a return trip, your vessel should still stay under 400k. Quite generally, I've been wondering if I should cut down on the busywork. All the transfers take a lot of time set up and frankly, they're not that hard to do. We all know how much it takes to get to Minmus; show that you have enough and just teleport. Similarly, it took me 2200m/s to get from Minmus surface to a low Eve orbit on Gilly's inclination -- for all I care everyone may just flare off that amount and spirit their vessel into place.

Talking about dV, would you be willing to share a few figures? How much did you need to get from Minmus Surface to LEO, and how much for the propulsive entry? It looks like you have prolly enough fuel, but in the name of due diligence I will download your craft, determine the dry mass, and do my own calculations from the resources you're showing... but a) I'm about to leave for a road trip and won't get to do that before monday at the earliest, and b), you're taking a great leap from Minmus Surface to Eve mid-entry. I don't think I'll have to see everything that happens in between, but some storytelling and data would be nice.

Incidentally... KER would be perfectly alright, as would be the use of MJ or any other autopilot. (again checking fron page) Yup, I've been saying so from day one. I hope you and @jinnantonix haven't been holding back on the assumption that this was literally a pure stock challenge?

23 minutes ago, ManEatingApe said:

The Rhino may seem an interesting choice, the rationale behind the decision was that significant parts of this mission required high dV vacuum maneuvers, and the Rhino provides both a good ISP of 340 and a good TWR for such a large craft.

And congratulations for making it work! It would have never occured to me to leave it dangling idle for the first part of the ascent, I always capped it off with a Mammoth -- leaving me without a deep space engine for getting to Even in the first place, and as an upper stage alone it's just too damn expensive. By using it for all the transfers you get your money's worth. Smart move!

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@Laie , at the risk sounding like I am nitpicking, I think including the transfer detail is very important for this challenge for a number of reasons.  It's true that designing a low cost Eve Ascent Vehicle is the hardest part by far (hats off to @ManEatingApe for that extraordinary effort).  The next part is the EAV surviving Eve entry.  You need to carry heavy heat shields, or enough fuel after the Kerbin-Eve transit to decelerate to 1500m/s as ManEatingApe did, even with repeated aero-braking at Eve you need fuel in the tanks for that final entry.  The crew return vehicle (BTW, you actually did say something about getting the crew back, I checked ... twice) , this adds weight which consumes fuel during the Kerbin-Eve transit, so maybe need to add some drop tanks.  I had considered using command chairs for the RV, but I interpreted your requirement here as needing pods for the Kerbin re-entry, can you clarify?)  Anyway, the RV increases the craft total weight, so need to add fuel/engines for the Kerbin launch and Kerbin-Minmus transit.  It all adds up.  My EAV was just under $600k including ISRU, heat shields, fully fuelled etc, but when you add the RV and the Kerbin launch boosters it adds >50% to the total cost on the launchpad.

Edited by jinnantonix

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@jinnantonix Yep, I stated that the crew needs to be recovered. Emphasis in brackets has been added just now, but the sentence before has been there since day one.

Regarding the use of Hyperedit, I determined that 2200m/s and a 2m/s² acceleration are sufficient for Minmus-Eve. I also still remember how long it took me to set up and perform all the maneuvers, and don't think it's strictly necessary for everyone to waste that much time. So if you follow that (by now) well-trodden path you may flare off the required amount of dV and just teleport. The "flare off" part is important, though, and if you insist to doing it on less dv or follow another flight plan, you're on your own.

Regarding command chairs, you got it right: not for landing or ascent. ManEatingApe's command chair on the orbiter is fine, though, assuming it's just for control when docking. If some poor sod has to sit there for days or weeks, that's not okay.

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14 hours ago, Laie said:

Talking about dV, would you be willing to share a few figures? How much did you need to get from Minmus Surface to LEO, and how much for the propulsive entry? It looks like you have prolly enough fuel, but in the name of due diligence I will download your craft, determine the dry mass, and do my own calculations from the resources you're showing... but a) I'm about to leave for a road trip and won't get to do that before monday at the earliest, and b), you're taking a great leap from Minmus Surface to Eve mid-entry. I don't think I'll have to see everything that happens in between, but some storytelling and data would be nice.

 

 

13 hours ago, jinnantonix said:

I think including the transfer detail is very important for this challenge

I didn't think anyone would find the Minimus -> Eve transfer details interesting, but guess I was wrong!
Fortunately I hadn't deleted the saves, so I took a few extra screen shots and added to them to the previously linked album.

Without further ado here's the gory details. (unless specified otherwise, when calculating dV I'm using the 340s ISP of the Rhino).

Stage 1: Kerbin Orbit at Minimus's radius
Mass: 724.3 tons, Fuel: 536.3 tons, dV: 4,499 m/s
(I'm including 30 tons of ore from Minimus, that we'll refine once in low Eve orbit, towards the fuel mass)

From here, we dive to low Kerbin orbit for maximum Oberth when ejecting.

Total dV needed so far:  202 m/s + 141 m/s = 343 m/s

aElPb6v.png

Next, in order to get 0° inclination around Eve, we fix inclination for another 387 m/s.

Total dV needed so far: 730 m/s

08SqnMr.png

Finally to brake into low Eve orbit, takes another 1,580 m/s

Total dV needed so far: 2,310 m/s

8D3GPeG.png

As we well know, maneuver burns don't go perfectly so let's see how we did once in low Eve orbit...

Mass: 367.5 tons, Fuel: 179.5 tons, dV: 2,236 m/s remaining

So we actually used 2,263 m/s vs our estimate of 2,310 m/s, coming out ahead slightly!
The small discrepancy is more than likely due to the mild aero-braking from a few passes in Eve's high atmosphere.

MKFK2mk.png

Finally just before descent, we pump 32 tons of fuel into the refueling tug.

After detaching, our final dV figure is calculated using the 315s ISP of the Mammoths (as the Rhino on its own wasn't enough to slow down)
Mass: 330.2 tons, Fuel: 147.5 tons, dV: 1,829 m/s remaining

Orbital velocity is 3,213 m/s, so less 1,829 m/s gives a final speed of 1,384 m/s (neglecting gravity and aerobraking)
or about 1,500 m/s as mentioned before.

oOzuO8E.png

 

13 hours ago, Laie said:

ManEatingApe's command chair on the orbiter is fine, though, assuming it's just for control when docking. If some poor sod has to sit there for days or weeks, that's not okay. 

Correct - Jeb was only on the chair for a few minutes to dock with the tug, in keeping with the spirit of the challenge.

13 hours ago, Laie said:

@jinnantonix Yep, I stated that the crew needs to be recovered.

To keep things absolutely fair (especially since the poor crew were abandoned on Gilly) - let's treat this entry as an honorable mention.
At the very least it shows that there's scope to make plenty of profit on this contract!
 

Edited by ManEatingApe

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Well, I enjoyed this challenge so much, I am going to do it again.  Next time I will really trim down the craft to be super cheap.  It may be a few weeks before I complete though, I am very busy at work.

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@jinnantonix regarding your PM, if you load ore on the pad you're still not allowed to refine it until you landed somewhere else. That's a bit silly, I have to admit, as you must carry large ore tanks and it makes sense to utilize them as well (I certainly would if I did this in a career context), but I couldn't come up with a simple and understandable rule... the first posts in this thread were people wondering what I was trying to say with regards to loading ore on the pad.

Hence "No mining or refining until you've landed on another body" which I thought was pretty clear.

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5 minutes ago, Laie said:

@jinnantonix regarding your PM, if you load ore on the pad you're still not allowed to refine it until you landed somewhere else. That's a bit silly, I have to admit, as you must carry large ore tanks and it makes sense to utilize them as well (I certainly would if I did this in a career context), but I couldn't come up with a simple and understandable rule... the first posts in this thread were people wondering what I was trying to say with regards to loading ore on the pad.

Hence "No mining or refining until you've landed on another body" which I thought was pretty clear.

RIghto, that's exactly what I thought you meant.  So basically you must launch with 30t of ore, and land of Minmus with 30t of ore.  Got it.  So how do you know that an entry has met with that criteria based on the screenshots?

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Just now, jinnantonix said:

RIghto, that's exactly what I thought you meant.  So basically you must launch with 30t of ore, and land of Minmus with 30t of ore.  Got it.  So how do you know that an entry has met with that criteria based on the screenshots?

Nope, you got it wrong. You must carry ore tanks for this challenge (how else would you get ore from Eve to Gilly), but nowhere do I say that they have to be full at Launch Time.

I do say that, given that you carry those tanks anyway, it would be nice to use them.... but that my attempts to come up with a rule to that effect have only created confusion.

This is how I arrived at the "No mining or refining until you've landed on another body" rule.

Strictly by the letter of the rule it is not forbidden to carry ore on Kerbin takeoff. If you want to do that, go ahead! It would be a dumb thing to do, however, as you're forbidden from refining that ore until you arrive elsewhere. My advice: launch with empty ore tanks and start mining when you arrive at your destination.

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1 hour ago, Laie said:

Nope, you got it wrong. You must carry ore tanks for this challenge (how else would you get ore from Eve to Gilly), but nowhere do I say that they have to be full at Launch Time.

I do say that, given that you carry those tanks anyway, it would be nice to use them.... but that my attempts to come up with a rule to that effect have only created confusion.

This is how I arrived at the "No mining or refining until you've landed on another body" rule.

Strictly by the letter of the rule it is not forbidden to carry ore on Kerbin takeoff. If you want to do that, go ahead! It would be a dumb thing to do, however, as you're forbidden from refining that ore until you arrive elsewhere. My advice: launch with empty ore tanks and start mining when you arrive at your destination.

LOL, I so totally misundertood.   Thanks for clarifying.  I am relieved, if I don't need to carry the ore from Kerbin to Eve , this means my current design is now pretty close to completion.  Just need to figure out how to land on Eve without heat shields.  It needs a lot of fuel to decelerate from orbit to 1500m/s.  Currently thinking it might be necessary to refuel on Gilly prior to Eve descent.

Edited by jinnantonix

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Here is my design so far, showing main craft and the last stages of the Eve Ascent Vehicle, which uses a Mainsail and two Reliants /drop tanks.  Using MechJeb now for the Eve ascent - very helpful.  Also having the Terrier in line (reversed) with the main craft and with an ISP=345 helps with those tight transfers where maximum fuel efficiency is needed (although extreme patience is called for).  The solution is passing all the tests,  I even have a chute for landing on Kerbin!  I expect to do the mission and video soon.  Only question is whether I need to refuel at Gilly to have enough fuel for the powered landing on Eve.

qzlPA74.png

3so7fcC.png

 

Edited by jinnantonix

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6 hours ago, jinnantonix said:

Here is my design so far, showing main craft and the last stages of the Eve Ascent Vehicle, which uses a Mainsail and two Reliants /drop tanks. 

That's looking positively penny pinching! :)

I noticed some struts here and there - you might be able to shave a few more funds off with judicious use of auto-struts.

Also, bizarrely the small docking port is way more expensive than the regular sized variant.

 

6 hours ago, jinnantonix said:

I even have a chute for landing on Kerbin! 

Luxury! Back in my day, we were so poor that Kerbals head butted the ground at 50 m/s and were glad of it.

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Eve-350-landed.jpg

10 hours ago, ManEatingApe said:

Luxury! Back in my day, we were so poor that Kerbals head butted the ground at 50 m/s and were glad of it.

...and here I am, bringing not only a RV that's capable of a gliding (if somewhat rough) landing, but a parachute to boot.

Sorry about not coming back to you earlier; I've silently added you to the front page but haven't taken the time to reply. I've been pretty busy over the week (and next week probably won't be any better), and this weekend I've flown my mission all over again with a slightly modified vessel.

Above you see my lander/lifter; after many iterations I brought it down to 350k and was pretty confident it would be impossible to beat. You've given me quite a surprise when you *started* at that figure. Now I'm eager to get my own submission out of the door before it becomes obsolete. Sorry about that, I'll get back to you.

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On 11/11/2018 at 9:43 PM, ManEatingApe said:

I noticed some struts here and there - you might be able to shave a few more funds off with judicious use of auto-struts.

Also, bizarrely the small docking port is way more expensive than the regular sized variant.

 

Thanks, I had forgotten about the struts, I have now fully "autostrutted" the craft, and that saved a few pennies.

I tried using the standard docking port, but it increased drag for the Eve ascent, and generally caused issues.  So I sucked it in and went with the expensive docking port junior.  It also looks neater on the top of the pod.

Mission is now under way!

Update 1: Just arrived at Eve.  No way I have enough dV to decelerate to 1500 m/s on Eve atmospheric entry, so currently maneuvering  to refuel at Gilly.

Update 2: After some aerobraking, now in low Eve orbit, with plenty of fuel , ready to land

Edited by jinnantonix

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