PakledHostage Posted February 27 Share Posted February 27 (edited) This is a challenge that I enjoyed hosting years ago in the early days of KSP1 and I figured I'd dust it off now again because it's something we can do while we wait for the first round of bug fixes in KSP2: Build the following rocket and launch it into a stable orbit around Krerbin (i.e. PE above 70 km) using the minimum delta-V possible. The rocket contains: MK1 Tin Can capsule MK16 Chute TD12 Decoupler between the tin can and fuel tanks FL-T800 fuel tanks (qty 2) LV-T45 Swivel engine Launch the rocket into orbit and capture a screenshot showing the PE, AP and delta-V remaining. Don't forget to include the chute and decoupler in your build, because it makes a big difference to the delta-V remaining (and your kerbal's chances of getting home). Attempts must be hand-flown and cannot use MechJeb or other means of assistance and/or automation. I will try and maintain a leader-board on here once a day. Here's my entry - 384 m/s remaining (it should be easy to beat because my AP is too high): Note: You can get PE and AP to display at the same time by right clicking on them. Leader-Board =========== 1. Bingmao (70.1 km x 70.2 km, 792 m/s remaining) 2. Lt_duckweed (70.3 km x 70.9 km, 781 m/s remaining) 3. AdamKSP (70.5 km x 71.9 km, 739 m/s remaining) 4. pakledhostage (71.2 km x 73.7 km, 710 m/s remaining) 5. speeding mullet (70.1 km x 81.4 km, 642 remaining) 6. draradech (70.2 km x 70.7 km, 527 m/s remaining) 7. Little 908 (70.0 km x 74.3 km, 431 m/s remaining) 8. klapaucius (79.0 km x 80.2 km, 402 m/s remaining) Edited March 29 by PakledHostage updated leader-board Quote Link to comment Share on other sites More sharing options...
Draradech Posted February 27 Share Posted February 27 (edited) 527 remaining, KSP2 0.1.0.0.20892 (for future reference) Edited February 27 by Draradech Quote Link to comment Share on other sites More sharing options...
PakledHostage Posted February 27 Author Share Posted February 27 (edited) Congratulations @Draradech! That's going to be pretty tough to beat! I will add you to the leader-board. (Can you maybe film a video showing your technique? That's better than I've ever seen anyone do.) Edit: I should add that there may yet be some room for improvement over Draradech's result. This challenge is a variation of the Goddard problem, so variation in thrust profile during the ascent may yield a few m/s improvement. Edited February 27 by PakledHostage Quote Link to comment Share on other sites More sharing options...
Draradech Posted February 27 Share Posted February 27 Sure. First, I'm not using the map screen for this, the indicators below the navball are sufficient. Technique: Launch. Wait for 50 m/s. Start leaning over, keeping heading directly on the right border of the prograde marker until 45°. Stay at 45° until 10 km altitude. SAS to prograde, switch to orbit relative. Wait until AP is 2:00 in front, keep it there by throttling until AP is 70km, stop burn. At 0:15 to AP keep it close to 0:15 by throttling until orbit. Got 496 in this video. I'm sure this can be improved, I didn't even try to optimize yet. (527 was my second try, this video is third) Quote Link to comment Share on other sites More sharing options...
PakledHostage Posted February 27 Author Share Posted February 27 Awesome! Thank you. I will try that myself later. Quote Link to comment Share on other sites More sharing options...
Speeding Mullet Posted February 28 Share Posted February 28 642 remaining. First try and I wasn't being terribly efficient so I think it can be beaten pretty convincingly. Technique was to launch full throttle, then start gravity turn, throttling down to about 66%, before throttling up to 100% at about 20 degrees. Cut off engines about 71km, then circularise at full throttle SAS to prograde. KSP 0.1.0.0.20892. Had fun, thanks! SM Quote Link to comment Share on other sites More sharing options...
PakledHostage Posted February 28 Author Share Posted February 28 (edited) Good job @Speeding Mullet! I will add you to the leader-board. And to your point about more being possible, I tried about 10 times (revert to launch is one's friend on a challenge like this...) using a hybrid of your technique and @Draradech's technique and I was able to pull off orbit with 710 m/s remaining. I never would have thought it possible this time yesterday, but there's still room for improvement because my orbit was higher and more elliptical than it needed to be: and Edited February 28 by PakledHostage Quote Link to comment Share on other sites More sharing options...
PakledHostage Posted February 28 Author Share Posted February 28 I suspect what's happening is that we're taking advantage of the LV-T45 "Swivel" engine's higher ISP at higher altitudes by lobbing it up, then coasting and then burning a second time to circularize. And in light of how quickly the delta-V remaining numbers are going up, I expect that there's a bit of room yet for improvement... Quote Link to comment Share on other sites More sharing options...
Klapaucius Posted February 28 Share Posted February 28 I only got 402, but I learned a lot doing this challenge. I love challenges like this. Does not take a lot of time, and I am a better player for having participated. I've played a lot of KSP1, but spent a lot more time with planes, so my rocketry skills are not what they should be. @Draradech: After a my first few pretty pathetic attempts, I decided to follow you advice, and I nearly doubled my Delta V! Quote Link to comment Share on other sites More sharing options...
Lt_Duckweed Posted February 28 Share Posted February 28 (edited) 771 m/s remaining in a 72.5km x 72.2km orbit. Tilted over to 70 degrees above horizon by 110m/s then full throttle till apoapsis leaves the atmosphere, then circ at apo. Next attempt, tilted over slightly faster, 70.9km x 70.3km orbit, 781m/s left Edited February 28 by Lt_Duckweed Quote Link to comment Share on other sites More sharing options...
PakledHostage Posted February 28 Author Share Posted February 28 (edited) Excellent. Thanks for submitting entries @Klapaucius and @Lt_Duckweed! I will update the leader-board. Edit: I should add that I am really impressed by the precision of some of the flying that I am seeing in these entries. Especially @Draradech's nailing 70.2 km x 70.7 km in a burn worthy of an IRL orbital insertion. Edited February 28 by PakledHostage Quote Link to comment Share on other sites More sharing options...
Speeding Mullet Posted March 13 Share Posted March 13 On 3/1/2023 at 7:14 AM, PakledHostage said: Edit: I should add that I am really impressed by the precision of some of the flying that I am seeing in these entries. Me too! I can't even beat my first try any more, must have been beginner's luck! SM Quote Link to comment Share on other sites More sharing options...
AdamKSP Posted March 22 Share Posted March 22 Here's my attempt before I have to take a break. I may try and get a bit better later on. Thanks for the challenge!! Quote Link to comment Share on other sites More sharing options...
PakledHostage Posted March 24 Author Share Posted March 24 On 3/22/2023 at 2:06 PM, AdamKSP said: Here's my attempt before I have to take a break. I may try and get a bit better later on. Thanks for the challenge!! Excellent. I will update the leader board. Quote Link to comment Share on other sites More sharing options...
Little 908 Posted March 24 Share Posted March 24 (edited) I kinda suck at this, but I at least managed to get 6th https://imgur.com/a/YsjQf9E do I get bonus points for landing back near the launch pad? lol Edited March 25 by Little 908 Quote Link to comment Share on other sites More sharing options...
PakledHostage Posted March 25 Author Share Posted March 25 8 hours ago, Little 908 said: do I get bonus points for landing back near the launch pad? lol You win the internet. Congratulations. Quote Link to comment Share on other sites More sharing options...
Bingmao Posted March 28 Share Posted March 28 (edited) I went straight up until I reached 50m/s Then a sharp turn to 70° As soon as the Prograde marker reached the Level Indicator, I set SAS to Prograde and keep on full throttle until AP was at 68km 20sec before reaching AP, I fired the engines Prograde and kept the AP ~20sec in front of me until the APwas >70km circularize Result Orbit: 71.504 x 70.635 km, (room for improvement) remaining deltaV: 785 m/s EDIT: Second try result: Orbit: 70.209 x 70.135 km remaining deltaV: 792 m/s Edited March 28 by Bingmao Quote Link to comment Share on other sites More sharing options...
PakledHostage Posted March 29 Author Share Posted March 29 And we have a new leader! Quote Link to comment Share on other sites More sharing options...
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