psyberduckling

I just removed the horizontal landing requirement for Duna, and the parachutes requirement totally. It was an unnecessary restriction to an already quite difficult challenge. Parachutes didn't really fit my idea of reusable, but I guess KSP lets you repack them (rather unrealistically, they'd be shredded in most of my landings). Re. challenge popularity, i guess I need to make some badges. I'm trying to builder a bigger version of my reusable vehicle, and using your idea of a deployable resource scanner probe, but I'm having some issues with spontaneous disintegration either on the runway or during reentry. 300t spaceplanes are hard to get right.

I'll do some testing on Duna, maybe the no parachute requirement is not sensible since the atmosphere is so thin. Tylo (and Eve) are the two most difficult bodies to reach and successfully return from, to the point where I'm not sure either is possible, the only possible way I can think of managing Eve would be to build a space plane which does not use air breathing engines at all, which would have to be huge because of the increased amount of fuel needed. Edit: Yeh, ok, landing on Duna either horizontally or without chutes is unrealistic, I'll edit the rules for it, I can get down to about 50 m/s a second horizontal, but seem to always crash into the side of a hill or the ground, nevermind the issues with slowing down after getting the wheels on the ground.

The problem I've found with the trip back (this was in an ISRU spaceplane), is managing to get an aerocapture via Kerbin's atmosphere, it cost me quite a lot of fuel to get a capture despite nearly burning most of the fittings off the ship. The dV to get a Kerbin encounter isn't that expensive (though to be fair I was coming from a refuelling stop at Pol which made things a lot easier, travelling from the outermost moon, it's fairly easy to drop your periapsis down to just above atmosphere so you can abuse the Oberth effect to it's maximum, especially at Jool which has a very deep gravity well).

I'd imagine so, not very efficient compared to burning all your fuel as close to the sun as you can get without burning up. Then again no harm in getting a little boost off Jool on the way out (I don't think it'll be that much of a boost, you'll be going that fast that it's gravity won't deflect your orbit enough to get a very significant gravity assist).

I've been messing around with Eve gravity assists to get to Jool. For it to work you must have your periapsis inside Eve's orbit for the first assist, with a good trajectory you can get your orbit after the encounter close to a 1:2 resonance with Eve, to get a second gravity assist from Eve in order to reach Jool you need to shift your Periapsis inside Eve's orbit again (You can't get a good gravity assist when your periapsis is aligned with Eve's orbit). Burning retrograde at apoapsis until you get a second encounter is one way to do it, though if you're lucky you can probably use Kerbin, Duna or maybe Dres. A second gravity assist from Eve should be enough to get you well beyond Jool's orbit, with a bit of luck you should be able to get an encounter with Jool. A formula for getting resonant orbits is: a1 = factor^2/3 * a0. a0 = semi-major axis of the body you're trying to achieve resonance with. a1 = semi-major axis of your orbit. And factor is the difference between your orbital periods. T1 = T0 * factor. Where T1 is your orbital period, and T0 is the orbital period of the body you're aiming for resonance with. Semi major axis can be worked out via: a = (periapsis + apoapsis + 2 * radius of the body you're orbiting) / 2. For a 2:1 resonance you want your semi major axis to be roughly 1.59 * that of the body you're aiming for resonance with. I.E. your apoapsis should be close to 2.2 times your periapsis (your periapsis will be roughly equal to Eve's semi-major axis after a gravity assist). You don't want exact resonance otherwise you'll have an encounter with Eve at the same place every time coming directly from behind it which makes gravity assist impossible. Edit: An alternative to the retrograde burn at apoapsis is to perform a plane change at apoapsis before the second Eve encounter so that at your second encounter with Eve you'll either be coming from slightly above or below, and the gravity assist will work by cancelling your plane change. Edit2: I tried the plane change thing for Eve, it's not worth it, you're better off burning retrograde at apoapsis to lower your periapsis inside Eve's orbit so that your next encounter has enough of an angle for gravity assist to be useful, less dV, and makes it much easier to line up the encounter especially if you manage to get close to 2:1 resonance.

To be fair, the first 950m/s can easily be burnt at or very close to periapsis in ~45 burns of one minute length, just have to dodge moons, and get your ap/pe aligned correctly for your transfer window. Hell, you don't even have to dodge moons for the first 800 or so m/s. The last 1000m/s is the problem, though if you use an Kerbin-Eve-Jool transfer it's much less which could be burned close to or at periapsis. Gravity assist via the Mun probably isn't worth it for the 200 m/s dV you'd save, given in a low TWR ship, you're already jumping through enough hoops to align your pe/ap correctly with the transfer window, accounting for deflection by the Mun's gravity becomes very hard (Ideal gravity assist would give you a 90 degree deflection, but i don't think the Mun's gravity is enough at the velocity you'd need to be going to get to either Eve or Jool). I've done this a few times in low TWR ships to save fuel (admitedly not quite so low as the ship in question). edit: Mostly I've done this in my ISRU space plane, didn't quite have enough fuel to get to Minmus to refuel if I just burned straight, then when I leave Minmus I burned for an orbit with a periapsis just above Kerbin atmo, aligned with the transfer window. I tried to do the same back from Jool, but I messed up the exit angle (as an aside you can get almost anywhere with very little fuel from Pol using this trick, the problem is slowing down when you get where you're going, when you're going 9000 m/s at Jool periapsis adding a little dV goes a long way).

I did it with separate survey probes, if you want to include survey probes in your payload and detach them (nice idea, I might include that on my next design), you must bring them back with you to Kerbin. It's within the spirit of the challenge. Mostly the rule was to prevent detaching a small lander and leaving the main craft in orbit. Edit: updated the rules, added a restriction that mass left in orbit must be under 2.5t (which should be more than enough for a medium sized probe). Shame we can't mine Xenon.

Here's my entry for the minimalist category the Asp Mk1. Weight: 4.4t Craft file here Dissatisfied with the available cockpits from C7 aerospace and Kerlington Model Rockets, we built our own from a few spare parts we found lying around the VAB. We are disappointed with the launch crew, they seem unable to park the plane on the runway with the handbrake on. Our pilot bob did manage a precision landing on the KSC runway, though we are disappointed he couldn't manage it without a parachute.

Or just put some lift or control surfaces vertically as far back as you can on your plane, or increase the size of any existing ones, putting vertical fins on the end of swept wings is great for this, as the tip of the wing is often behind the main fuselage.

Ok, here's my entry Mission log: - Successful takeoff to Orbit from Kerbin. - 3 1 minute burns at periapsis at the ascending node with Minmus. - Wait for Minmus window, and burn for an interception orbit. - Landed successfully on Minmus, Didn't stop to rescue the stranded kerbals from the ill fated maiden voyage (They where short about 50 m/s dV in order to land safely). - Refuel Liquid fuel and Monopropellant. - Successful takeoff to Minmus orbit. - Wait for Jool window and burn for a Kerbin orbit with a periapsis around 75km, aligned correctly so that burning at Periapsis sends us off to Jool. - Burn for Jool. - Aerocapture at Jool. - Adjust orbit for Laythe intercept. - Aerocapture at Laythe (with some help from thrusters). - Adjust orbit to a 60km circular orbit, and wait for the landing site to be in daylight (previous successful flight of the PythonMk1 already landed here but with no fuel left). - Successful landing (show above). - Realise there's no ore to mine at the landing site, and have to send an ore scanning probe to find Ore. - Realise I forgot to put a communication antenna on the probe and send a second one. - Fly a short distance to a good location for mining. - Refuel Liquid fuel, monopropellant and oxidiser (leaving one oxidiser tank empty, same as in the initial launch configuration). - Burn for Laythe orbit. - Burn for Pol orbit, trying and failing to dodge all the other moons. - Land successfully at Pol for refuelling. - Notes about refuelling at Pol, you can't just startup the ISRU and mining equipment, and leave it running whilst timewarping at the space center, it requires baby sitting since they deactivate due to not being in contact with the ground (even though they are), something weird about the surface of Pol. - Take off from Pol, and burn for a Periapsis around Jool of about 250km timed with the departure window for Kerbin. - Completely miss Kerbin, and have to adjust the orbit to incept the second time around. - Aerocapture around Kerbin coming from Jool with my orbit was impossible, burn huge amounts of fuel just to avoid being flung back out into deep space. - Use aerocapture and remaining fuel to lower orbit to around 80x80km. - Burn to de-orbit somewhere near KSC. - Slightly overshoot KSC (ended up coming down by the island with the runway), and glide/fly back to KSC on remaining fuel. - Land successfully at KSC. All tolled it took around 25 years mostly due to mishaps (to be fair, this was the first manned mission I've flew to another planet's SOI). Fitting an ISRU ore tank and mining gear on a spaceplane with enough dV to reach and land on Minmus turned out to be more challenging than I envisaged. Here's the file for the ship (I'm aware it has a few problems, the LV-Ns refuse to burn fuel from some of the tanks and the action groups need some love, but this is what I flew, so I'll save improvements for the Mk3). http://cyberiantiger.org/PythonMk2.craft

The goal is to build a space plane which can reach and land on as many of the planetary bodies in the Kerbol system as possible without the aid of other ships, and return the vessel and 100% of it's parts back to Kerbin. ISRU use is permitted (and encouraged). Rules: 1. *The craft may not lose any parts in flight, no decoupling or explosions allowed. 2. The craft must lift off horizontally provided the body has an atmosphere. 3. The craft must land horizontally provided the body has an amospheric preassure greater than 0.4 (i.e. Eve, Kerbin, Laythe). 3. The craft must return to Kerbin and land successfully. 4. The trip must be done without the aid of other vessels (No fuel transfers from other ships or refuelling stations, no connecting up to a mothership and flying to another body). 5. Mining and refining ore is encouraged, but not required. 6. Stock parts only. 7. No you can't use the cheat menu, there's a reason it's called the cheat menu. *Resource scanning may be accomplished separately or you may detach a probe from your vessel (which must be recovered before returning to Kerbin). The total mass left in orbit must be under 2.5t. Craft will be scored by bodies successfully visited, 1 point for each. Honorary mentions to the lightest and heaviest entries. My entry to follow (I have one, which successfully flew Minmus -> Laythe -> Pol -> Kerbin). Note: this is distinct from the K-Prize in that it permits ISRU use. Leaderboard: pyberduckling - PythonMk2 (Minmus, Laythe, Pol) Special mentions for impressive feats: ....

Don't have detailed logs, and don't care much for badges, but this ship made it easily (went the direct route, no slingshot via Eve) She's 43 parts, 53.1t, 6.1m high, 12.4m wide and ... 31.3m long. Here's the craft file: http://cyberiantiger.org/PythonMk1.craft Fuel tank balancing is a pain, and don't use the physics acceleration during re-entry, it tends to cause her to oscillate the nose up and down violently before exploding into little bits.

Well I managed to get to Laythe, no ISRU, no overlapping parts didn't even use gravity assists to lower the dV needed. Might be possible to do the round trip with a lot of gravity assist and carrying a bit more lox. Not really a competition entry, I didn't manage to return it to Kerbin this time.