ManEatingApe

Let's get the ball rolling with an actual entry! The first task is to find a suitable spot to land. A kOS script scans Tylo's equator looking for the highest point. At longitude -73.7927 it finds a nice mountain at 9,074m elevation. There are higher spots elsewhere on Tylo but choosing a location on the equator makes targeting a precise landing easier. Next task is to design a suitable craft. A second kOS script simulates a constant altitude landing burn, predicting the final TWR, burn duration and delta-v needed, so that the craft design can iterate quickly without needing trial and error. Lastly, let's fly the mission. A third kOS script controls the craft, performing a precision landing at our desired location. Let's see how the simulation compared against the actual mission. Predicted Actual Duration 434s 450s Delta-V 3,266 m/s 3,383 m/s Initial TWR 0.63 0.63 Final TWR 0.95 0.97 Not too shabby! The main difference is that the simulation ignores the final vertical landing phase for simplicity, causing a slight discrepancy. For anyone considering an entry, please feel free to use, tweak, modify and improve the scripts linked in this post.

This is fun challenge! I can think of 2 different strategies that could result in a lander with a final TWR of 1 (wrt Tylo local gravity). Both approaches will require top notch piloting skills and nerves of steel... Constant Altitude Burn Good description and discussion in these threads: What is the most efficient way to deorbit+land? Most Efficient Way to Land: Suicide Burn, good. Constant Altitude, better... Gravity Turn... Best? A constant altitude burn is more delta-v efficient than a suicide burn as TWR drops. In a nutshell the approach is: Enter circular orbit at the same altitude as the location that you want to land at (e.g on top of a handy mountain) Thrust mostly parallel to the surface, pitching up just enough to keep vertical velocity zero and altitude constant (hence the name of the maneuver) In theory with a TWR of 1, come to a perfect landing with the craft vertical (hovering against gravity) and horizontal velocity at zero. Brake Pad Insanity Burn This second approach is slightly more Kerbal: Find a nice flat patch of ground Come screeching in at ~2,300 m/s, using engines to keep vertical velocity zero Brake to a halt using wheels

Another way to test the comparison is to simulate a descent similar to how KSP models it. TL;DR A constant altitude descent consistently uses less delta-v than a suicide burn. The difference is bigger the lower the TWR of the craft, closing very rapidly to negligible values as TWR increases. Here's a chart showing values simulated for Tylo: I modeled the descent trajectory using the differential equations from the paper: Optimal Trajectory Planning for the Apollo MoonLanding: Descent, Ascent, and Aborts by Duncan Miller A kOS script integrated the differential equations numerically using Euler's method. During testing this agreed very closely with reported values from KSP, so seems to be similar to how the game code models things. The script simulated a "perfect" descent from a 30km circular oribt of Tylo to sea level. For the constant altitude burn a single pass for each TWR was enough. For the suicide burn, an iterative approach was used to determine the right altitude to set the periapsis when starting the burn.

It's an fun problem, optimizing for mission simplicity (or working around script limitations). Not totally sure on the overall mission profile yet but one idea I'm thinking of is parking a mothership in circular Jool orbit just outside Tylo, then 5 separate landers (one per moon). Not the most efficient delta-v wise but would keep mission profile relatively simple.

Description There has been plenty of healthy debate on this forum about the merits of flying missions manually versus various forms of autopilot assistance (for example MechJeb). This mission thread will not attempt to address that debate, but instead try something a little different by taking autopilot assistance to the ridiculous extreme: Completing the Jool-5 challenge with no player input whatsoever! Required Mods kOS (Kerbal Operating System) is the core mod enabling this attempt. kOS adds a virtual computer to craft that allows execution of scripts of arbitrary complexity. kOS-EVA will support control of Kerbals on EVA (presumably by implanting a chip in their head Black Mirror style ). RSVP library will handle the complexity of orbital rendezvous and transfer planning. Details A common approach to solving complex software problems is divide and conquer. Break the problem down into smaller chunks (recursively if necessary), solve each of them individually, then integrate the parts into a cohesive whole. The Jool-5 challenge is no different and can be broken down into the following sub-problems: Ascent: Launching into orbit from a planet's surface (both atmosphere and vacuum). Descent: Landing intact on the surface of a planet from orbit (both atmosphere and vacuum). Docking: Joining with another craft in orbit. Rendezvous: Transfers from planet to planet, and from ship to ship. Orchestration: Execute each of these steps in the correct order for the correct craft (there will be multiple craft). Plan My approach will be to solve each of these sub-problems one at a time, then attempt to stitch them together into a complete mission attempt. The initial solutions will probably be far from optimal, as the primary goal is to prove the overall feasibility. However a nice benefit of breaking the problem into chunks is that individual parts can be improved and tweaked over time (for example the descent script could be improved without requiring changes in other scripts).

The only wrong direction is if you capture into a retrograde orbit of Jool! (have done this by accident) Seriously though, the great thing about KSP is that there are always many ways to accomplish things. Want a pod..use it! Want all the science..do it! Want to use nukes...go for it! You can optimize in any of several areas e.g low mass, low part count, low risk, low mission complexity, low requirements in real time. Then you can always go back and try the same mission in a different way just for kicks. It's not strictly related to your question, but it's also fun to toss a probe into a one-way trip into Jool's atmosphere and let it get crushed. You can transmit some extra science and the added mass requirements are not too high, if you let aero-braking do most of the work.

For the Tylo lander, have you considered a command chair instead of a pod? The mass savings would be considerable. A flags and footprints only Tylo lander can be in the 2 to 2.5 ton range (budget some more than this for the Science Jr) Your plan to re-use the ascent stage of the Tylo lander for Val, Pol and Bop is a good idea and a great way to save some parts and mass.

4,000 m/s dV should be more than enough to return from Jool to Kerbin, including capturing propulsively into Kerbin orbit. A thought occurs based on your description (but a picture would be even more helpful) - where is your transfer trajectory intercepting Kerbin? You want the PE of your transfer to be a close as possible to the PE of Kerbin. This way your craft's velocity and Kerbin velocity are mostly aligned, so you only need to cancel out the hyperbolic excess. If you're intercepting Kerbin away from the PE of the transfer orbit, then you'll have a significant radial component. Hopefully this sophisticated diagram help show what I mean: Another suggestion: Tylo and Laythe are wonderful for gravity assists when arriving/leaving Jool, due to their large mass and high orbital velocity. With a little practice you can also eject directly from Laythe/Tylo orbit into a Kerbin intercept.

This is a fun challenge with plenty of potential! A single stage vessel to Eeloo at periapsis needs about 4,500 to 5,000 m/s from LKO. High but not impossible for an efficient design. The obvious choice of ion engines is feasible but has some drawbacks. Solar power is basically non-existent at Eeloo's apoapsis and Eeloo's gravity is high enough to make landing on the low TWR of ions alone challenging. Best bring some alternate power source and some extra landing engines. A Rapier/Nuke combo would also be quite effective and probably simpler to execute the journey. To get the ball rolling here's an entry applying the strictest interpretation of the rules. Single stage from Kerbin to Eeloo's surface without any refueling. A fuel cell tucked away in a non-stageable fairing provides enough power to run 2 ion engines consistently. Just enough fuel to make it to the surface intact! I'm sure that the creative and ingenious folks on this forum can come up with plenty of other approaches. Full Album Link @Nicodo123 You could consider tweaking the challenge to attract some healthy competition. For example you could split entries into ranks, here's one idea: Gold: Kerbin to surface of Eeloo and back to Kerbin without any refuelling whatsover. Silver: Kerbin to surface of Eeloo without refuelling along the way. Bronze: Kerbin to surface of Eeloo with a pit stop. Alternatively, ranking by cost / mass / part count are also popular options.

That's gonna be a little tricky (but not impossible)! One idea to consider is a separate tug craft, with RCS and a decent reaction wheel that could wrangle your side by side rockets together.

Nice entry, added you the leader board in the chair category. I liked the truly minimal design and taking advantage of the extra EVA fuel allowed by the new 1.11 inventory system.

That's an ingenious and entertainingly Kerbal discovery! I like the idea of your unfortunate Kerbal clutching an extra tank of fuel all the way down and back. Sure, I'll allow it: I'm intrigued if it will work.

Gotcha - the parts remain outside the bay, but the nosecones are placed inside it. Clever, but I'll have to disallow it. Either live with the drag of the nosecones or streamline things into fewer stacks. Flags producing body lift at an angle is a confirmed bug. The ESA exploit challenge feels like a better home for flag related chicanery.

Thanks for asking for clarification in advance, I appreciate it. This spirit of this challenge is to get as cheap as possible, within the constraints of the normal intended physics of the game. Excessive clipping is just one aspect of that philosophy. Bearing that in mind... Hard no on both of these. (they would come under the Wheaton rule category). The heat shield trick is amusing, but falls under the same category of unintended physics glitches as the (now fixed) drain valve exploit or various other Kraken-tech. Any entry using this would go straight to the Rogue's Gallery. You could submit a clearly labelled entry just for fun on that understanding. I'm a little dubious on this, but perhaps a little more explanation would help before making a decision. As I understand it parts that are completely contained within a service bay or fairing are not considered for aerodynamic drag, so I'm not sure about the advantage of adding a nosecone inside the bay. Absolutely yes and I would encourage it! Both DLCs are completely fine. There's even a number of different approaches you could consider: Propellers in addition to rapier/whiplash to assist in lower atmosphere. A separate propeller mothership entirely, that carries and releases a more conventional rocket powered craft (e.g SpaceShipTwo / WhiteKnightTwo). This mothership could then return to KSC. A propeller powered recovery vessel that is launched separately to the initial craft and recovers the parts dumped around Kerbin, returning them to the KSC for 100% recovery value.

Nice work on the ruthlessly reduced reusable refinement. You retain the top spot in the category.