GoSlash27

Update: This challenge has been completely broken by Tsevion. http://forum.kerbalspaceprogram.com/threads/85728-Ion-glider-collier-trophy!?p=1548671&viewfull=1#post1548671 The first time in the history of KSP, a Kerbal has been placed in orbit and returned to Kerbin in a stock installation using an ion SSTO composed of all stock parts and absolutely no glitch exploits. It doesn't even *have* control surfaces! Best, -Slashy

I really want to single out Tsevion for special recognition for this achievement: http://forum.kerbalspaceprogram.com/threads/85728-Ion-glider-collier-trophy!?p=1548671&viewfull=1#post1548671 There aren't very many "holy grail" accomplishments in KSP, but this is one of them and he accomplished it today. He placed a Kerbal in orbit and returned him safely to the surface in stock KSP with an SSTO composed of all stock parts using ion drive and absolutely no physics loopholes. This has never, *ever* been done before! A monumental achievement and we're all extremely proud for him! Best, -Slashy

Mind= blown. I'll just be over here in the corner, gently weeping... Best, -Slashy

Congratulations! You broke the challenge and made history!

Last update I had, all of the science had been collected. The one question was whether the drill had actually collected anything for the spectroscopic analysis. Has anyone got an update on that? If my understanding is correct (and I'm not sure it is), then it really doesn't matter if contact is reestablished with Philae or not. Best, -Slashy

Congrats! Getting it done the first time is the hard part. It should be a lot easier for you now. Best, -Slashy

Leaderboard is updated. MabDeno, That's the tough part. We know the parts will do the job, but can it be done without overloading the game? Tsevion, You're just a stone's throw away now. I'm pulling for you, 'cuz I'm not close. Best, -Slashy

Actually... not that bad. Better to be lucky than good. This is the mission as witnessed by the mothership: http://s52.photobucket.com/user/GoSlash27/slideshow/KSP/Branson I'll do the sub-orbital vehicle tomorrow. Best, -Slashy

I've got it sorted out. The sub-orbital package gets to the right altitude under power and handles nicely during landing. The mothership handles like crap, but well enough for the mission. The trick from my end is to figure out where to set up the launch so both parts end up back at KSP and to document both parts of the flight. *edit* Dammit! I'm not ready. I TLDR'd the rules and the mothership isn't manned. Looks like I've got a lot of rework in my future. Best, -Slashy

12 passengers is a lot, but I think do- able. I'll tinker with it for a bit. -Slashy

Mitch, Maybe we should plug in an additional step in the process; 2a) Build a turbojet powered plane that can carry a payload of 3 tonnes to 29KM at 2KM/sec. Best, -Slashy

Well, Getting the balance means building it balanced from the ground up rather than tacking on additional parts. If you've made it past step one, then you understand how to make an airplane statically balanced and dynamically stable. If you've made it past step 2, then you know how to juggle lift and drag and make an aircraft that's stable at high speed (which is somewhat different from step 1). Step 3 just incorporates additional parts and an action group, but the same principles apply. Build it statically neutral with the CoM coincident with your fuel so the CoM doesn't shift. Build it with some dihedral and yaw stability so it tends to correct it's own deviations, and a little nose- heavy. Build it with the higher drag stuff in back and the lower drag stuff in front so it won't want to flip at high speeds. Use high wing loading for less drag at altitude, but not so high that you can't get there. For step 3, just pretend that the LF rocket engine and additional fuel/ oxidizer is payload. Use the air-breathing mode to get it to the jump- off point and let 'er rip. If you'd like some rough rules of thumb I use, I'll pass them on. Best, -Slashy

Mitch, SSTOs really aren't that hard once you've got the hang of them, even in stock KSP. The trick is learning how KSP aerodynamics work and building accordingly. Rather than banging your head against the wall in frustration, why not just walk yourself through a development program? Step 1: Build a basic jet-powered aircraft that is dynamically stable, so that it can take off, fly to the island, land, and return safely to KSC. Step 2: Build a turbojet powered aircraft that can reach 29KM altitude and 2,000 M/sec and return safely to KSC Step 3: Based on the results of step 2, build an SSTO that uses a liquid rocket engine to bridge the gap from 29KM and 2K to orbit. Step 4: Build an SSTO using only RAPIER engines. Best, -Slashy

BrainiacBlue, The problem I see with this challenge is the mothership will become debris in the atmosphere once you get far enough away from it and KSP will eliminate it. Best, -Slashy

I actually know the answer to this, but it's pretty far off- topic. The short version is that the GPS signal is below the noise floor. Rather than detecting the signal itself, the receiver detects the signal's effect on the randomness of the background noise. Longer version: As a crude example, say the background noise floor is a series of coin flips. We sample 1,000 flips and expect 500 heads if there's no signal, and our signal might skew that a bit, like 524 heads. If we get a result that's consistently non- random, then we lock onto the frequency and start tracking whether we're getting more heads or more tails. We expect the results to flip heads to tails or vice-versa at regular intervals and we compare how accurately the changes track with each of our satellite's unique fingerprint (the PRN code). When we get an exact match, we know which satellite we have and we know that it's telling us a data "1". If our result is exactly wrong, OTOH, we know that it's the same satellite, but it's sending us a data "0" because the satellite sends zeroes by inverting it's PRN code. That's the gist of how the receiver works. If you want to know how we work out all our fancy results from that, hit me up on PM. I don't mind sharing it, but it's way off- topic for this thread. Best, -Slashy

As of right now here's the best tip I can give you: Use the strakes as wings and use the bare minimum to get you to 28KM up at 2KM/ sec in level flight under jet power. Other helpful but less-critical info: -For intakes, I've had good luck with the ram air intakes and shock cones (1 per engine) or radial intakes (4 per engine). -Don't bother adding RCS propellant. You have plenty in the cockpit. -1 RAPIER is adequate for 12 tons of aircraft, including the Rapier itself and it's fuel. -Fuel/ oxidizer ratio (not counting whatever you're using after orbit) is about 1.23 KG of fuel for every KG of oxidizer. Best, -Slashy

Jumped from 4 engines to 6, but it didn't gain me much. This last few hundred m/sec is gonna be a pain 39,152@ 1,938. 6 engines, 10 tanks, 48 wings.

K^2, I'm an avionics tech and we play around with these sorts of figures all the time. I have no idea what signal levels are expected in this case, but I do know that a decent antenna and receiver can easily pick up a signal at 4nW. That's about -54dBm. I have worked on TACAN receivers using 1/4 wave antennas that need to be intentionally adjusted to reject signals below -98dBm, since it could potentially cause navigation errors. That's down in the hundreds of femtowatts range. The GPS receiver in your phone can detect signals down to -125 dBm or even lower. HTHs, -Slashy

Tsevion, Glad to have you back! Updating the leaderboard now. I'm right behind ya. 36,340@ 1,802 using 4 engines, 7 tanks, and 28 wings. http://i52.photobucket.com/albums/g13/GoSlash27/KSP/kTHULU/Kthulu4_zps312b8b44.jpg The rest of these are unofficial. I'm adding this info as I tinker to keep track of the gains. 36,876@1,823 using 4 engines, 7 tanks, 30 wings 36,611@1,797 4 engines, 7 tanks, 32 wings. Best, -Slashy

New official records for Manned. (edit) Update: http://i52.photobucket.com/albums/g13/GoSlash27/KSP/kTHULU/Kthulu3_zps56ea751f.jpg 36,006 @ 1,785 This one is at 26 wings, 4 engines, and 7 tanks. I spent 10KG to get the small reaction wheel, but this meant I had to put on a battery so no bonus. Best, -Slashy

Last run of the YERTL. 31,340@ 1,271. I have learned how to set up a flying wing so that I no longer need a vertical stabilizer, but this one had the mass spread out too wide, setting up a horrible yaw oscillation. It was also underpowered. My next design will use a similar wing layout, but will cluster the mass closer together. Hopefully this will give me better control with my puny torque. Best, -Slashy

TheBedla, Thanks for the kind words. This was originally intended to answer the question of whether an Eve SSTO was possible using wings and ion engines. Clearly, it's not. And ion SSTO is never going to be cost- effective from Kerbin, since conventional fuels are so much cheaper and easier. Now it's just down to doing it for the sake of doing it, but I think what we're doing here will have a positive effect on the development of lighter, cheaper, and more efficient SSTOs using other propulsion systems. Besides... it's kind of addictive! Sure you don't want to try your hand at it? Best, -Slashy

I forgot all about answering this! Sorry, Rocketeer! I have never had any success with altering the static angle of attack of the wings or thrust angles. It seemed to throw off the static balance so bad that my results were worse than just leaving them straight. AFA the tank/ engine ratios, all of my best results came from keeping the flight time at 35-40 minutes. Any more than that and the added mass and drag outweighed the advantage of additional flight time. Best, -Slashy

Good run. I'll get the leaderboard updated for you. I don't know how many wings you've currently got. Previous runs show that for your configuration (4 engines 8 tanks) the optimal number of wings should be in the neighborhood of 20-24. Counterintuitively, you may have better luck with 7 or even 6 tanks. It should make up for the reduced flight time by improved climb performance and acceleration. Congrats, -Slashy

What Laie said. Having multiple fuel lines come into a single tank will work fine, but having multiple fuel lines coming out of it will not. The script will only ever follow one of those paths and the others will be ignored. Best, -Slashy