Ex's mission to Eve - complete "explore", and "flyby" missions, collect mucho science!

[ex_]

My first post here... sorry so long As noted below, I did this mission in this particular way because that's what interested me, not necessarily because it was the quickest, easiest way. Constructive feedback welcome... please note this was also written as a post on another forum, where people new to KSP would be reading. That is why it is written in the way it was written.

The mission

Iam spending a ton of time doing missions in this game, and honestly,the journey of getting from ideas, plans, testing, troubleshootingand then finally, completion, is so interesting that I just had totype up a story...

Kerbinis your home planet in KSP. Eve is a planet that is really the2nd closest to Kerbin. You might think its only marginally moredifficult to get to it than the closer Mars clone "Duna". But its gravity is a little stronger than Kerbin's, and more denseatmosphere, unlike Duna which has thinner atmo and lighter G's.

I'mdoing a couple contracts right now where one is to do a "fly by" of Eve. That just means to get somewhere within the "sphere ofinfluence" of the planetary body. (within its gravitydimple for you general relativists). I always like to, wheneverpossible, complete two or more contracts/objectives with the samemission. That yields you more space bucks for your launches. In real life, if an astronaut is going up to play golf on the moon,for instance, he is often strongly encouraged to take some scienceexperiments too, just so it wasn't a total waste of time.

Collecting"Science" is a huge part of career mode in KSP. Itallows you to progress through the skills tree so you have access toall parts.

Themissions up right now:

• 
  
• Fly by Eve
  
• Explore Eve (contains many objectives)
  
• Explore Gilly (same)
  
• and a self-imposed "bring 'em back alive and with a lot more science than the above contracts mandate"
  

Imentioned above that Eve has stronger grav and denser atmo thanEarth's analogue, "Kerbin". As a result, you mustpush through friction causing gasses as you ascend, AND fight thehigher gravity in order to get into orbit. Remember, my missionwas to explore Eve, which means I must land and transmit some data. However, my self-imposed goal was to grab more science on the surfaceand return it to Kerbin for max return on investment (as if acting asa mission director for a real space program). That meanswhatever lands, must then also ascend. Landing is fairly simpleon an atmospheric planet. Simply use the atmosphere to slowyou, and deploy chutes. (sometimes lots of them). Theproblem with this notion is that to leave Eve, a vehicle must becapable of changing its velocity (Delta V) by 10,000 m/s, as opposedto just 3,400 m/s for Kerbin. (there is a chart out there that helpsyou with figuring out this stuff)

So,as you can imagine, in order to carry so much "delta v",you must have a very large ship. You'll be carrying a lot morethan you need just to make the journey, in order to make sure you cando the landing and ascent. Going there is easy. Getting alittle science is easy. Getting a lot of science could eithertake lots of small trips, or one big one. Just for theengineering puzzle that it would require me to solve, I've opted forone BIG mission.

The vehicles and some of what has been completed to date.

Here is the Eve Lander. It is by far, the largest thing I have had to build yet in this "game".

It has some intersting features. Each tank/engine combo on the periphery will drop in pairs as they are depleted, in what's called "asparagus staging". Symmetrically dropping stages in such as way that when mass is no longer needed, it is discarded AND fuel lines between the earlier and later stages results in leftover stages being fully fueled after each pair is dropped.

The midde area is the final stage in getting back up to a mother ship to leave for Kerbin.

Science based pieces at the bottom are discarded prior to liftoff from Eve (after Kerbal goes out and collects all the data)

Kerbal then gets on the Top part by climbing a ladder. Ther kerbal then rides in a command chair, rather than a heavier type of command module. Otherwise, this ship would need to be EVEN bigger.

And remember, this isn't the lifter to get it from Kerbin to Eve, just to ascend from Eve after we get there. To even get to Kerbin orbit, we first need something capable of sending this already giant piece, to orbit.

...which requires an even larger piece of equipment!!!! Believe it or not, this would have had to be even bigger if this design didn't go the route of emptying out a lot of the fuel for the Eve Lander stages, making the mass we need to push to Kerbin orbit, much smaller. Still, look at how big of a lifter is needed for this lifter!

But wait... that gets you to orbit, but now your mostly empty on fuel and need to actually get to Eve. What I decided to do was not to create a single ship that would go to Eve. For the same reasons that we want to drop spent stages as they are not needed, we also don't want to send a super massive ship to Eve if we don't have to. We'll drop what we don't need along the way. But, to initially reduce the requirement for leaving Kerbin in the first place, we can't (if we are to stick to my plan for the mission) lift something that is capable of lifting off Kerbin, pushing toward Eve, landing and most importantly, ascending from Eve, pushing to Kerbin (not to mention my Gilly(moon) requirement), and do return maneuvers and eventually land on Kerbin. That would be economically inefficient and increasing a bunch of the undesirable things that can happen along the way.

To do this, we have to launch separate pieces, and probably refuel pieces before putting them together and finally pushing to Eve. That should be fine. I've done this at a smaller scale for Duna missions and saved tons of "kash" along the way by first sending a Duna bound ship to Mun for refueling. It makes the lift requirement, and consequently, your mission budget, much smaller. I have re-usable ships at Mun and Minmus with fuel on standby for occasions such as these...

Here is the stage which will eventually mate up with the Eve lander seen above and push it to Eve. It will also serve as the return vehicle for the scientist who will go in the Lander piece, and the Engineer who will go in this piece.

Ascending... This one will eventually drop large tank stages when it is pushing the mission to Eve. But for this liftoff, it will not auto-stage so that I can refuel them. Luckily, this packs enough punch to lift itself regardless. Afterall, it has to eventually push something that is over 500 tons to another planet. I tested its capability by placing 500 tons of weight on it in the editor and seeing if it had enough Delta V to both push to Eve, but also return.

Oh, I forgot to mention that the pointy bit is intended to go visit Gilly after the Scientist returns from Eve in the bigger lander. Or, he might do the easier thing first to prepare... that could be decided en route.

So yyyyyea... we needed to refuel these things, right? It's kind of going to be a pain, but this is how we'll do it. A new tanker is designed and put out at Minmus. My existing ones were way too small and would require dozens of trips. Actually, as it turns out as I am probably 2/3 through with this refuelling effort to date, this large tanker still requries a few trips, but is small enough not to become impossible to use. I also wish I would have used a slightly smaller engine. This one is probably too massive and powerful. It is also sort of sluggish to maneuver and that has caused some problems along the way. BUt there it is...

The hangout time with the fuel depot, waiting to be filled up. The biggest job, by a light-year, that this station has ever had to do. It served Duna missions very well, and helping the whole Kerbin system stay fueld up, but now I think it's definitely time for an upgrade.

Completing the trip back to Kerbin orbit to refuel it. Remember - this fuel is all essentially free. The cost of putting it all here was paid back a while ago now, and I'm just trying to make the game more of an RPG and be cost-effective wherever I can. Doing things outside of Kerbin's atmosphere means we can avoid having to lift fuel through thick atmosphere and against stronger gravity. Most of any mission's fuel requirements will be to leave Kerbin (or Earth) in the first place. The rest of it is all hitting the right trajectory at the right time and coasting until you arrive.

As you can see just from the picture, if that ship is mostly empty, it's going to take a few trips to fill! Good thing, is that without installing a different mod, Kerbals do not require life-support resources that can be depleted over time. They just need to be kept safe

This here, is the fuel depot's lander, which drops down to grab new ore, lifts it to the station for processing. IMO, this is the way to start out doing it, rather than turning it into fuel on the surface, and sending THAT to orbit. Processing in orbit means you can convert the operation over to producing other fuel types. It also makes missions like these possible in the first place. Otherwise, if I had no network of vehicles and stations built up around the Kerbin system, as shown before, this vehicle would have to be much more massive that it already is!

this requires several trips just to fill up the large tanker, unfortunately.

To reduce the number of trips, i've now gone the route of using two big ore pods at once, and increasing the fuel for the lander to compensate. The trade-off is that you cannot gather ore when both pods are absent from the surface (my ore extractor should have been fitted with a permanent ore canister), but that does not really matter because time can be sped up later to gather ore almost instantly. (It takes 12 game days for this to produce two of these pods full.)

I'll post more later as it develops. This is a days long thing to do. I'm actually nearing the end of it, and have several days already invested. It's fun though A lot like an endurance race in GT, pausing a few times in a 24hr race, just to say "I did it".

Thanks for reading.

[Rath]

Good introduction for people new wondering why you would ever do anything.

[ex_]

umm... thanks for the bump, I guess?

[Mister Dilsby]

Nice craft and a good, comprehensive report so far. So what made you go with those engines for the lander? Curious as to the engineering behind the scenes, as most Eve ships use some combination of Mammoths and Aerospikes (due to large thrust and high Isp, respectively)

ETA: Also recommend this move to "Mission Reports" -- the Writing section is typically for KSP themed made-up stories e.g. fanfic.

Edited November 2, 2015 by Kuzzter

[ex_]

If a moderator wants to move, that's fine with me. I was sort of unclear about where it should go. Thanks.

For the engines, I did not see good TWR coming out of experimenting with the Aerospikes, after setting up many stages and fuel. If you get close to or exceed the 10k delta v requirement to get back up to mother ship, you also get a relatively small TWR. I did not want to set myself up for not having good TWR and then wasting some Delta V on my way up, thus making the ship fail to ascend. Not to mention, finding I dont have enough Dv to help keep the thing stable on the way up.

I have gone back, since you asked the question and it made me second guess things... the drawing board shows that I could reduce some mass by replace a couple of the big engines, but then there will be stages along the ascent that have poor twr, and for my first trip to Eve, I feel I need a higher TWR for reducing risk. (this is my first attempt at Eve, so want to be careful)

The mammoth was unattractive as a lifter for Eve mostly because it would mean the kerbal would be atop a tall rocket, need to climb down, and then back up again. That seemed logistically difficult to guarentee out in the field, so I opted ofr keeping the kerbal close to the ground so that exiting and getting back on would be very fool proof for him (it is a guy in this case )

I do see a couple places where I can reduce mass and do a smaller mission later. But again, I think it all boils down to wanting higher TWR the whole ascent, and not being entirely sure how it will go, so I wanted to err on the side of giving it too much.

Depending on alternate designs in the future, I may be able to get it down in the 250-350 tons range, rather than the 500 tons it is presently at. That's what a couple rough builds just now turned up as potentials. Again, lower TWR the whole way up makes me nervous, though... (yes I am adjusting for Eve in Engineer)

THanks for the kind words, BTW.

[DuoDex]

Punted to Mission Reports.

[Mister Dilsby]

For the engines, I did not see good TWR coming out of experimenting with the Aerospikes, after setting up many stages and fuel. If you get close to or exceed the 10k delta v requirement to get back up to mother ship, you also get a relatively small TWR. I did not want to set myself up for not having good TWR and then wasting some Delta V on my way up, thus making the ship fail to ascend. Not to mention, finding I dont have enough Dv to help keep the thing stable on the way up.

Makes sense-- FWIW I used a ship with 7 mammoths (6 in the first stage, one center core) and an upper stage orbiter that had two aerospikes. That ship got five Kerbals comfortably to orbit--I got them to the surface and back by transferring from the orbiter cabins to a docked surface rover. (though I did cheat to move the science into the orbiter ) Looking forward to seeing you land your lifter--that's the really hard part these days