sdj64

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About sdj64

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    Sr. Spacecraft Engineer
  1. @JacobJHC has my permission to make the new Jool 5 Challenge thread when this one closes. Thank you for stepping up. I'm glad to have someone with experience with completing the Jool 5 Challenge twice, including one Level 3, and also experience running other challenges. For all of those who have a mission in progress, don't worry - you will probably still be able to submit in the new Jool 5 Challenge. If there is a change with the Making History expansion that makes it difficult or impossible to judge equally, I'll keep this one open for a while upon request. @PhoenixRise86 I'm sorry, I can't see your original file names. I'll take another look, it seems like the second half of the album is roughly in reverse order so I should be able to follow it well enough.
  2. @PhoenixRise86 Congratulations, you have completed the Jool 5 Challenge on Level 1! I like your Falcon Heavy-style launch and your mission was above and beyond the minimum for level 1 with 3 crew and science. It's rare to see a Jool 5 without nuclear engines but yours was efficiently done with just Terriers for your transfer stage. @foobar Congratulations, you have completed the Jool 5 Challenge on Level 1! And you are now the low-mass and low-cost record holder for 1.2-1.3! You had a great low-mass entry with an efficient spaceplane. Controlling that Tylo lander must have been a great feat of piloting! How did you get off the ground with the tipped-over lander, without a reaction wheel? @McQuacker Looks like a great mission, but can you put your pictures in order? It's hard to follow such a large album out of order! Thanks for your patience, everyone. As you can probably tell I've been getting slower to reply over the past couple of months. Since I started a new job and moved to live on my own, I have much less time for KSP and I think that it would be best for someone with more time to take over the Jool 5 Challenge. I'm officially closing for new entries on the release day of the Making History expansion (March 13). With all of the new features I think the Jool 5 will need some significant updates, and could even have a mission from the mission builder! Thanks everyone for the continued support and ongoing entries to the challenge. You all have pushed the boundaries and delivered with creativity and quality. If you are interested in taking over or contributing in the future, please let me know.
  3. I'll submit the one I was flying when I saw this challenge. Not made for the points, obviously, due to its mass and part count. But it does check just about all of the boxes. Mass: 714 tons, Parts: 425 Horizontal takeoff rocket SSTO, can make it to Minmus from Kerbin, Tylo and Laythe capable, can go anywhere but Eve. 3 science packages, each on a deployable craft, and carries 40 Kerbals. Needs a Mun gravity assist to get to Minmus for the first refueling, but after that you can go anywhere without assists. Has 1.3 TWR full, so the burn to Jool is very quick. ISRU is fuel cell powered and goes extremely quickly with 10 or more engineers on board. Ironically, it only runs out of electricity when the ore is very high concentration, because the converter uses it all up... Claiming every bonus except "quick start". 714*0.95*0.8*0.9*(0.8)^3*0.9*0.8*0.8*1.1 = 158 It is rather hard to land. Normally, it can tail-land, and then tip over softly with the help of some aerospikes under the nose. On Kerbin and Laythe it can reenter and land like a plane. On Duna it works, just open the cargo bays to keep the drag in front and enter backwards. Taking off uses the nose aerospikes to get it off the ground. I keep discovering minor things wrong with it (latest: forgot solar panels on the mini-lander) so it hasn't actually been anywhere other than Minmus yet, but that's how I plan to do it. I have tested the tail land tip over, and reentry and flying, on Kerbin. Stats in the VAB:
  4. @astrobond Congratulations, you have completed the Jool 5 Challenge on Level 1! And with 32.5 tons you have the lowest mass of any entrant in 1.2-1.3. Those fancy spaceplane parts are costly, though, putting you in 3rd place for low cost. I really liked the bird-like design of your plane, and the cockpit on the back was a unique choice. It's a solid ISRU all-in-one craft, and was flown well too.
  5. The large probe cores do have the capability of remote-piloting other craft from the craft the probe core it's attached to, without connection to KSC (provided there's also a pilot on board and a relay antenna). The 2.5m one can even do it through another relay, while the 1.25m one needs a direct link to the controlled craft. For that reason, it's helpful to have one on an orbiting mothership or manned base with unmanned landers, rovers, or satellites. So I generally use them as a sort of "remote control center" more than a probe core. I also like the big golden one for replica or real-world inspired satellites, if it fits in the size I need. I think having some kind of limit for small cores, like number of engines, number of control surfaces, or mass, would help large cores be more relevant. Say, the Okto2 can only control 4 active engines and 4 fins, while the 2.5m core would be needed to control a Falcon heavy replica with 27 engines.
  6. @McBalsam Congratulations, you have completed the Jool 5 Challenge on level 3! I'm impressed by the splitting SSTO design, I've seen them done before but not for a Jool 5. And your landers are small and efficient too. I liked the simultaneous approach with all of the landers splitting and gravity-assisting to their respective moons, it was quite the unique maneuver. And a very well-edited video. All of this coming from someone with only 3 posts! Be careful with the clipping though (on the mothership "bridge" section). This was really close to being disqualified but I don't think any drag tricks were abused, and your landers fit into the cargo bay without clipping. As the other commenters said, this is not allowed. You can visit an asteroid base once, if the ISRU is only on the asteroid base and not on the ship. That will count as your refueling mission. Another clarification: you may only meet with the refueling mission once. For example, you can't leave a full fuel tank in orbit of each moon either, even if they were all dropped by the same ship. Sounds like you're learning a lot! While we're talking about rule 6, this would actually be the perfect opportunity to use your refueling mission. It's exactly what the rule was intended for in the first place - rescuing a ship that doesn't quite have enough.
  7. So, I did see one error in my calculation: When I assumed the SSTO payload fraction of 35%, it didn't include any engines or wings used for Kerbin ascent (because the payload fraction challenge specified an inert payload). My test craft had a mass of about 45 tons full and 30 in orbit, for 66%, which puts chemical engines back in the realm of possibility for the Tylo landing and ascent. You can also use your efficient (ion or nuclear) engine in conjunction with your more powerful engines for Tylo, which could maybe save you some more. Good analysis, it's nice to see similar delta V figures. You might be able to save 200m/s by landing at speed and braking, and your first 200 m/s could use your most efficient engine to build up speed across the ground? I tried incorporating these changes into a craft, but I'm still coming up short. It has about 1000 m/s too low delta V on the "high thrust" part, and its TWR is only 0.5 where it needs to be 0.8 at Tylo landing. It also is missing electrical systems to run the ions and was tested with infinite electricity on. My spreadsheet says I can devote 5 tons to non-tank stuff, and I'm sitting around 6.5. How to increase the thrust and decrease the engine mass? I think it might be better to just use the rapiers on closed cycle - the engine mass savings might make up for the lower efficiency. If I use those, my non-tank budget drops to 4 tons, but I also lose 1 ton of Terriers, so it's an even trade and I get higher thrust for the Tylo landing.
  8. I played around a bit in the VAB with Kerbal Engineer, with little success. I could get maybe 3/4 of the way there on delta V. So then I turned to excel, because while it only takes one success to prove something possible, only math can prove something impossible. I'm not 100% sure on the assumptions I made, but I believe it is mathematically impossible to do a stock Tylo surface SSTO. The spreadsheet works from bottom to top, using the rocket equation to find the wet mass after each step of the mission and finally telling you what mass you have to devote to your fuel tanks and what you have left over for stuff like wings, cockpit, and engines. I assumed it takes 2000 m/s to go from Kerbin orbit to Tylo orbit, 4500 to land and ascend from Tylo, and 1000 to return home. With perfect gravity assists and piloting, you might be able to reduce those numbers. I also assumed the Kerbin ascent had a payload fraction of 35%, which was the highest I found in the recent payload fraction challenge. Edit: should have assumed much higher, because that fraction was an inert payload, not counting engines, wings, and systems. I got 66% in testing. Negative percentage for the "budget" line mean it's impossible to get the required delta V with that engine combination. https://drive.google.com/open?id=1ykMPBYGOo0YHkErJf0mClUfqGF-t1W5r
  9. The Mobile Base Challenge

    A short hop could mean 5 minutes (or some time) of flight time at 1.0 TWR or higher (or lower, if using wings?) for that world. Amphibious could mean it can travel 20km (or some distance) across water before needing to refuel. I agree that the tank capacity for fuels is sort of arbitrary? For example, I usually don't transport ore in a mining operation - all of my mining ships also have a converter, so I only put the smallest ore tank on. Also on Laythe, Eve, or Tylo, there's no chance that an ion craft will need to be refueled at the base - it can't get there in the first place. I'm sure everyone will disagree on what multipliers are best, but what number is being multiplied? Do you start with a score of 1 for meeting the requirements?
  10. The Mun 4 Challenge

    Cool challenge, I totally approve of a less-challenging "proving ground" for the Jool 5! I do like the scoring system, it seems to reward more interesting solutions and give it more excitement for the veterans as well. Take a single stage Mun lander. Add a parachute. You now have a Duna lander! okay you have to add about 200 delta V but that's not so hard to do
  11. Origami Steel Fleet

    I built one a while ago but then forgot about it when I changed the carrier design so a plane could ride outside. This plane was made for gathering science from Laythe, and needs to be carried in a Mk3 spaceplane that can land horizontally. The wheels are not powered, but it's not really a big deal - there are two Vernors in the front that push it backwards out of the cargo bay, and the engine can do the rest. It does have a big flaw, which is that it has no real cockpit so it needs a comnet connection to fly.
  12. Yes, science from Jool including its high and low orbit, and atmosphere, counts. Moon orbit space science also counts. Science earned from a lab does not count, and anyway you would have to land the lab because transmitting science does not count. Since turning ComNet off entirely is allowed, you can use your relays. You can also use any ore scans you have already performed, or send a scanning satellite separately ahead of the mission.
  13. Does orbital speed have to be Kerbin orbit? If so, can you leave Kerbin orbit and come back (getting a high speed in solar orbit and then diving back towards Kerbin)? Can you use gravity assists? Also, does it have to be manned and if so, are seats allowed? I do like the "king of the hill" style of scoring, where you have to beat all 3 of the previous best entry. It could get to the point where just one of the records is really impressive, and the other two could still be easily beaten. For example, I can think of a couple ways to game the space record, especially if the answer to some of the above questions is "yes"...
  14. Yes, that would be cool to see. As long as your rescale includes all of Jool's moons orbiting Jool in the same order and at least 1x their stock size (some rescales change Bop and Pol differently, for instance - just make sure they are not smaller than stock), it is allowed.
  15. Right here. It's the all-time low mass record holder, too. It was done in version 1.1 by @Nefrums